Patent Publication Number: US-10760538-B2

Title: Customizable engine air intake/exhaust systems

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 62/577,423, filed Oct. 26, 2017, U.S. Provisional Application No. 62/577,965, filed Oct. 27, 2017, U.S. Provisional Application No. 62/598,045, filed Dec. 13, 2017, U.S. Provisional Application No. 62/616,601, filed Jan. 12, 2018, U.S. Provisional Application No. 62/678,460, filed May 31, 2018, U.S. Provisional Application No. 62/687,461, filed Jun. 20, 2018, and U.S. Provisional Application No. 62/697,072, filed Jul. 12, 2018. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     This invention relates to the air intake and exhaust systems for internal combustion engines. 
     Description of the Related Art 
     When reciprocating internal combustion engines draw intake air from the atmosphere into the cylinders, the air often passes through various connecting passageways, such as pipes and chambers. In some cases, where increased power and/or thermal efficiency is desired, the intake air is compressed prior to entering the cylinders. To further increase the charge to the engine cylinders, the compressed intake air may also be cooled prior to introduction to the engine intake manifold. 
     After combustion, the exhaust gases are conducted to be discharged to the atmosphere, often passing them through pollution control and/or noise reduction devices. While in some automotive systems the air intake and exhaust systems may be separate from each other, in other automotive systems they may be interrelated, typically by way of a turbocharger, which is a mechanical unit that contains one or more turbines that are rotated by exhaust gases, which rotation in turn actuates a pump, such as a centrifugal or axial-flow pump, to compress intake air prior to entering the cylinders. 
     The design of the intake and exhaust systems can impact engine power and efficiency. Specifically, the path that the intake air must take to the cylinders can affect engine performance, with a lengthier and/or circuitous path reducing the flow rate and the air charge introduced into the cylinders. Likewise, turbocharging and intercooling often requires circuitous plumbing to deliver and regulate the flow of exhaust gases to the turbocharger and then to downstream components. In order to accommodate the various design requirements, intake and exhaust systems are often specific to a particular engine and vehicle platform, with only limited ability to reconfigure the design prior to vehicle shipment, and even less in the after-market. 
     SUMMARY OF THE INVENTION 
     The present invention provides compact and reconfigurable automotive internal combustion engine air intake and exhaust systems suitable for use in front-engine, mid-engine and rear-engine vehicles. The systems are designed to yield superior engine performance and to permit substantial increases in engine power by exchanging and adding relatively few principal components, which themselves are designed to cooperate and permit easy substitution. The components utilized in the systems of the present invention are inter-related and capable of being attached to and disconnected with relative ease to form various air intake and exhaust gas configurations. The systems of the present invention offer at least ten different configuration options, and are particularly suitable for an internal combustion piston engine having two cylinder banks of at least two cylinders each, each bank arranged in a row and inclined from the vertical so as to form a V. 
     In one aspect, the invention is directed to a system for configuring in different power stages an internal combustion piston engine having a first row of at least two cylinders inclined relative to a vertical plane, a second row of at least two cylinders inclined relative to the vertical plane, and the two rows of cylinders form a V configuration with the vertical plane being approximately equidistant between the two rows. The system comprises a Stage 1 package and a Stage 2 package. The Stage 1 package includes a first exhaust manifold adapted to be secured to the first row of cylinders for receiving and collecting in a plenum exhaust gases from the first row of cylinders, where the first exhaust manifold includes a first exhaust gas discharge aperture for discharging exhaust gases, the first exhaust gas discharge aperture is located at a first fixed spatial position when the first exhaust manifold is secured to the first row of cylinders, and there is provided first connecting means proximate the first exhaust gas aperture. The Stage 1 package additionally includes a second exhaust manifold adapted to be secured to the second row of cylinders for receiving and collecting in a plenum exhaust gases from the second row of cylinders, where the second exhaust manifold includes a second exhaust gas discharge aperture for discharging exhaust gases, the second exhaust gas discharge aperture is located at a second fixed spatial position when the second exhaust manifold is secured to the first row of cylinders, and there is provided second connecting means proximate the second exhaust gas aperture. The Stage 2 package includes a first turbo exhaust manifold adapted to be secured to the first row of cylinders for receiving and collecting in a plenum exhaust gases at least from the first row of cylinders, where the first turbo exhaust manifold includes a first turbocharger connection aperture adapted for mounting a turbocharger and for delivering to the turbocharger exhaust gases from either the first row of cylinders or the first row of cylinders and the second row of cylinders, a first exhaust gas passage aperture and third connecting means proximate the first exhaust gas passage aperture, the first turbo exhaust manifold being dimensioned so that the first exhaust gas passage aperture is located at about the first fixed spatial position when the first turbo exhaust manifold is secured to the first row of cylinders in lieu of the first exhaust manifold, and a crossover pipe assembly having a second exhaust gas passage aperture and fourth connecting means proximate the second exhaust gas passage aperture, and having a third exhaust gas passage aperture and fifth connecting means proximate the third exhaust gas passage aperture, where the fourth and fifth connecting means are each adapted for coupling to any two of the first, second and third connecting means. 
     In other aspects, there are provided further additional Stage 3, 4 and 5 packages, each of which yields substantial increases in engine power for exchange and/or addition of relatively few principal parts. These and other aspects of the present invention are described in the drawings annexed hereto, and in the description of the preferred embodiments and claims set forth below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic perspective view of a Standard Installation of the Stage 1 air intake-exhaust system of the present invention. 
         FIG. 2  is a schematic perspective view of the single outlet exhaust manifold first utilized in the Stage 1 air intake-exhaust system of the present invention. 
         FIG. 3  is a top view of the single outlet exhaust manifold first utilized in the Stage 1 air intake-exhaust system of the present invention. 
         FIG. 4  is a rear view of the single outlet exhaust manifold first utilized in the Stage 1 air intake-exhaust system of the present invention. 
         FIG. 5A  is a schematic front perspective view of a Standard Installation of the Stage 2 air intake-exhaust system of the present invention. 
         FIG. 5B  is a schematic rear perspective view of a Standard Installation of the Stage 2 air intake-exhaust system of the present invention. 
         FIG. 5C  is a schematic front perspective view of a Reverse Installation of the Stage 2 air intake-exhaust system of the present invention. 
         FIG. 6  is a schematic perspective view of the turbo exhaust manifold first utilized in the Stage 2 air intake-exhaust system of the present invention. 
         FIG. 7  is a bottom view of the turbo exhaust manifold first utilized in the Stage 2 air intake-exhaust system of the present invention. 
         FIG. 8  is a rear view of the turbo exhaust manifold first utilized in the Stage 2 air intake-exhaust system of the present invention. 
         FIG. 9  is a side view of the turbo exhaust manifold first utilized in the Stage 2 air intake-exhaust system of the present invention. 
         FIG. 10  is a top view of the turbo exhaust manifold first utilized in the Stage 2 air intake-exhaust system of the present invention. 
         FIGS. 11A and 11B  are perspective views of an exemplary turbocharger first utilized in the Stage 2 air intake-exhaust system of the present invention, with the  FIG. 11A  orientation particularly depicting the exhaust turbine portion and the  FIG. 11B  orientation particularly depicting the air compressor portion. 
         FIG. 12  is an exploded schematic perspective view of the turbocharger and turbocharger exhaust circuit first utilized in the Stage 2 air intake-exhaust system of the present invention. 
         FIG. 13A  is a schematic perspective front view of a Standard Installation of the Stage 3 air intake-exhaust system of the present invention. 
         FIG. 13B  is a schematic perspective rear view of a Reverse Installation of the Stage 3 air intake-exhaust system of the present invention. 
         FIG. 14  is a perspective view of the intercooler first utilized in the Stage 3 air intake-exhaust system of the present invention. 
         FIG. 15  is an exploded perspective view of the intercooler first utilized in the Stage 3 air intake-exhaust system of the present invention. 
         FIG. 16  is a perspective view of a single channel air inlet utilized in the Stage 3 air intake-exhaust system of the present invention. 
         FIG. 17  is a view of the single channel air inlet shown in  FIG. 16  which is sectioned on geometrical plane  305 - 2 B and viewed as shown by section line  2 B- 2 B′. 
         FIG. 18  is a view of the single channel air inlet shown in  FIG. 16  which is sectioned on geometrical plane  305 - 2 C and viewed as shown by section line  2 C- 2 C′. 
         FIG. 19  is a perspective view of the single channel air inlet shown in  FIG. 16  and its inlet seal assembly. 
         FIG. 20  is a front view of the single channel air inlet shown in  FIG. 16 . 
         FIG. 21  is a perspective view of an air outlet first utilized in the Stage 3 air intake-exhaust system of the present invention. 
         FIG. 22  is a view of the air outlet shown in  FIG. 21  sectioned on geometrical plane  305 - 4 B and viewed as shown by section line  4 B- 4 B′. 
         FIG. 23  is a view of the air outlet shown in  FIG. 21  sectioned on geometrical plane  305 - 4 C and viewed as shown by section line  4 C- 4 C′. 
         FIG. 24  is a perspective view of the air outlet shown in  FIG. 21  and its outlet seal assembly. 
         FIG. 25  is an exploded perspective view of a configuration of the intercooler system assembly utilized in the Stage 3 air intake-exhaust system of the present invention. 
         FIG. 26  is an exploded schematic view of the turbocharger, turbocharger exhaust circuit and single channel air inlet utilized in the Stage 3 air intake-exhaust system of the present invention. 
         FIG. 27A  is a schematic perspective front view of a Standard Installation of the Stage 4 air intake-exhaust system of the present invention. 
         FIG. 27B  is a schematic perspective front view of a Reverse Installation of the Stage 4 air intake-exhaust system of the present invention. 
         FIG. 28  is a perspective view of a dual channel air inlet first utilized in the Stage 4 air intake-exhaust system of the present invention. 
         FIG. 29  is a view of the dual channel air inlet shown in  FIG. 28  which is sectioned on geometrical plane  305 - 3 B and viewed as shown by section line  3 B- 3 B′. 
         FIG. 30  is a view of the dual channel air inlet shown in  FIG. 28  which is sectioned on geometrical plane  305 - 3 C and viewed as shown by section line  3 C- 3 C′. 
         FIG. 31  is a side view of the dual channel air inlet shown in  FIG. 28 . 
         FIG. 32  is a front view of the dual channel air inlet shown in  FIG. 28 . 
         FIG. 33  is a rear view of a turbo exhaust manifold pair utilizable in the Stage 4 air intake-exhaust system of the present invention. 
         FIG. 34  is a schematic perspective rear view of the Stage 5 air intake-exhaust system of the present invention mounted on an engine. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the embodiment of the present invention depicted in  FIG. 1 , there is shown an eight cylinder V-8 engine  700 . The “forward” portion or “front” of engine  700 , and like references, refers to those portions of engine  700  most closely oriented to the head of the arrow  920 , shown in  FIG. 1 ; for the engine of the preferred embodiment, the belt-driven accessories are located at the front of engine  700 . The “rearward” portion or “rear” of engine  700 , and like references, refers to those portions of engine  700  least closely oriented to the head of the arrow  920 ; for the engine of the preferred embodiment, the drive shaft will exit at the rear of engine  700 . Correspondingly, the “left” side of the engine is that side which is generally visible in  FIG. 1 , whereas the “right” side of the engine generally is not visible in  FIG. 1 . 
     In similar manner, references in this disclosure to the “forward” or “front” portion of any component or assemblage, and like references, refers to the portion of the component or assemblage oriented most closely to the head of arrow  920 , and reference in this disclosure to the “rearward” or “rear” portion of any component or assemblage, and like references, refers to the portion of the component or assemblage oriented least closely to the head of arrow  920 . Where arrow  920  is presented in a figure showing a component or components in isolation from engine  700 , it is assumed that the orientation of that component or those components when secured to engine  700  is with their respective arrows  920  aligned and pointing in the same direction, unless stated otherwise. 
     Furthermore, references in this disclosure to the vertical direction, or like statements, refers to the direction normal to the ground (the ground being generally parallel to a horizontal plane  106 , shown on edge in  FIG. 33 ). In the case of V-8 engines mounted in a conventional upright orientation, as depicted in  FIG. 1 , there is a vertically oriented geometrical plane  104  ( FIG. 1 ; also shown on edge in  FIG. 33 ) that passes through the crankshaft centerline  701  and is equidistant between the cylinder banks. In this disclosure, a horizontal line contained in this vertical plane  104  oriented parallel to the ground is said to define the longitudinal direction. Correspondingly, vertical plane  104  is sometimes referred to herein as longitudinal plane  104 . 
     Additionally, any of the set of geometrical planes perpendicular to longitudinal plane  104  and orthogonal to crankshaft centerline  701  may be referred to in this disclosure as a transverse plane (in this disclosure, all transverse planes are vertically oriented). 
     The particular engine shown is  FIG. 1  is an LS3 model 6.2 liter displacement small block V-8 engine, with fuel injection (marketed by General Motors Company). The concepts of the inventions described herein are particularly applicable to V-style engines generally; i.e., engines having two cylinder banks of at least two cylinders each, each bank arranged in a row inclined from the vertical so as to form a “V”, including V-4 engines, V-6 engines, V-12 engines, V-16 engines, etc. In the LS3 model engine depicted, the ignition system module has been relocated from above the air intake manifold  710  to below the engine  700 , in order to provide space above the air intake manifold  710  for certain of the features of the present invention, as described below. In addition, the valve covers depicted in  FIG. 1  provide additional space for use of taller valve trains, relative to stock covers. 
     The inventive systems described herein feature plural inter-cooperative components capable of being attached to and disconnected with relative ease to the engine and each other to yield substantial increases in engine power as the user may choose. In particular, the present invention provides five principal different engine configurations, referred to herein as Stages 1 through 5. Each stage develops increasing engine power than the last stage, using largely the same basic engine block and components throughout. The engine configuration in each of these stages is described below, together with the components used in that stage. Each stage can be installed in forward and reverse orientations, as is also described below. Further, given the flexibility of the present invention it is possible to create even further configurations beyond the Stages 1 through 5 expressly described herein. 
     Stage 1 Configuration 
     The engine  700  in its Stage 1 configuration is shown in  FIG. 1 . The engine  700  in its Stage 1 configuration is naturally aspirated; i.e., air is drawn into the cylinders without any air compression steps performed in the course of air induction, and in its Stage 1 configuration the exhaust gases are conducted to the atmosphere without making use of the enthalpy contained in those exhaust gases. The principal components utilized in the Stage 1 configuration are the Stage 1 air intake assembly  1  and the single outlet exhaust manifold  10 , described below. 
     Stage 1 Air Intake Assembly ( 1 ) 
     The Stage 1 air intake assembly  1  includes a dual rams-horn air intake  2  with two round input ports  3 , on each of which is secured a cylindrical air filter  4 , which is shown in  FIG. 1 . The air received through this air intake assembly  1  is delivered to the engine intake manifold  710  through an air intake connector  5 , a throttle assembly  702  and an air intake elbow  6 . Air intake connector  5  is a pliable conduit (such as silicone hose) that is secured to air intake  2  and throttle assembly  702  with two T-bolt clamps  8 . Although first identified herein in connection with the description of the Stage 1 configuration, the air intake elbow  6 , the throttle assembly  702  and the engine intake manifold  710  are common to all stages. 
     Single Outlet Exhaust Manifold ( 10 ) 
       FIG. 2  shows the single outlet exhaust manifold  10  for mounting to a cylinder bank of engine  700 . In the Stage 1 configuration, two single outlet exhaust manifolds  10  are utilized, one for each cylinder bank. The single outlet exhaust manifold  10  shown in  FIG. 2  is mounted in  FIG. 1  to the left cylinder bank of engine  700 . The single outlet exhaust manifold  10  for the right cylinder bank is in general design a mirror image of single outlet exhaust manifold  10  shown in  FIG. 2 . However, in the preferred embodiment of the present invention, the single outlet exhaust manifolds for the left and right cylinder banks differ in overall length. Where pertinent to this disclosure, the single outlet exhaust manifold  10  to be mounted on one cylinder bank will be referred to as single outlet exhaust manifold  10 L and the single outlet exhaust manifold for the other cylinder bank will be referred to as single outlet exhaust manifold  10 R. Where the designs features are the same for both of the single outlet exhaust manifolds, this disclosure will generically refer to single outlet exhaust manifold  10  for convenience of reference. 
     References herein to the “forward” or “rearward” portions of single outlet exhaust manifold  10  are made with reference to the orientation of exhaust manifold  10  relative to arrow  920  depicted in  FIG. 2 . Thus in  FIG. 1 , each single outlet exhaust manifold  10  is installed on engine  700  so that its rearward end  35  is proximate the rear of engine  700 . 
     Single Outlet Exhaust Manifold  10  Generally. 
     As shown in  FIGS. 2 and 3 , single outlet exhaust manifold  10  includes a manifold plenum  30 , for collecting exhaust gases from the engine. In the preferred embodiment, which refers for exemplary purposes to a V-8 engine, single outlet exhaust manifold  10  depicted in  FIGS. 2 and 3  includes four exhaust stack assemblies  20 A,  20 B,  20 C and  20 D (collectively referred to as exhaust stack assemblies  20 ), one for each cylinder of the left cylinder bank (for purposes of example) of the V-8 engine depicted in  FIG. 1 . From the cylinder bank to which they are secured, exhaust stack assemblies  20  channel exhaust gases to manifold plenum  30 , which collects and channels the collected gases to exhaust outlet  40 , from which the collected gases are discharged in the Stage 1 configuration to the atmosphere optionally through a catalytic converter and/or muffler, but without conducting the exhaust gases to intervening components, such as gas turbines, for extracting thermal energy contained in the exhaust gases for other use. 
     Manifold Plenum ( 30 ): 
     Manifold plenum  30  has a generally elongate cylindrical shape and a generally cylindrical wall  31 , as shown in  FIGS. 2 and 4 , and is generally circular in cross-section, as shown for example in  FIG. 4 , with an axial centerline  29 . 
     The forward end  34  of manifold plenum  30  is closed off by the first exhaust stack assembly  20 A (containing exhaust connector  23 A). The rearward end  35  of manifold plenum  30  defines exhaust outlet  40 , for discharge of all or substantially all exhaust gases received in plenum  30 . It is preferred that the diameter of manifold plenum  30  become greater along its length; i.e., from the forward end  34  of plenum  30  to the rearward end  35 . This growth in diameter yields an expanding cylindrical volume from the forward end  34  to the rearward end  35 , which serves to accommodate the introduction of additional exhaust gases from each successive cylinder along the length, as well as to permit the expansion of the exhaust gases. It is particularly preferred that the rate of diameter growth of manifold plenum  30  not be constant along its length from forward end  34  to rearward end  35 . Rather, it is particularly preferred that the growth in diameter of manifold plenum  30  start at zero at forward end  34 , then grow at an increasing rate from forward end  34  up to approximately the mid-point between forward end  34  and rearward end  35 , then grow at a decreasing rate from that mid-point up to rearward end  35 , and again reach a zero growth rate at rear end  35 . The result of changing the growth rate in this manner is to generally give an “S” shape to wall  31  in profile, from forward end  34  to rearward end  35 , as can be seen in  FIG. 3 . Put another way, the profile of wall  31  of manifold plenum  30  comes to be defined by an S-shaped curve rotated about the centerline  29  of plenum  30 , as in  FIG. 3 . 
     The length of manifold plenum  30 , together with first exhaust stack assembly  20 A, largely determines the overall length of single outlet exhaust manifold  10 . For V-configuration engines whose left and right cylinder bank discharge ports are offset (typically a consequence of utilizing crankshafts with crankpins arranged along the length of the crankshaft), it is preferred that the overall length of the single outlet exhaust manifold  10  for one of the cylinder banks not be the same as the overall length of the single outlet exhaust manifold  10  for the other of the cylinder banks. 
     Thus, referring to the single outlet exhaust manifold  10  visible in  FIG. 1  as  10 L, and the single outlet exhaust manifold not visible in  FIG. 1  as  10 R, it is preferred that the overall lengths of  10 L and  10 R (referred to herein as L 10 L and L 10 R; overall length L 10 L is explicitly shown in  FIG. 3 ) differ an amount approximately equal to the offset distance between the engine&#39;s left and right cylinder bank discharge ports, so as to result in the rearward ends  35  of each manifold plenum  30  of the single outlet exhaust manifolds ( 10 L and  10 R) terminating approximately in the same transverse plane (“Relationship A”). For example, in the case of the LS3 model V-8 engine shown in  FIG. 1 , the left cylinder bank is offset forward of the right cylinder bank. Thus for the single outlet exhaust manifold  10  visible in  FIG. 1  and shown in  FIG. 3 , L 10 L will be larger than L 10 R by an amount approximately equal to the cylinder bank offset distance. 
     It is preferred that rearward end  35  of manifold plenum  30  include means for coupling, so as to facilitate (in this instance) the passage of gas through exhaust passageway  40  to other components. In this disclosure, “means for coupling” includes any mechanical elements or components that facilitate the mechanical joining of two adjacent components. “Mechanical joining” includes joining mechanisms such as by use of screw threads, bayonet connections, mechanical clamping, but excludes any process of joining involving the melting of material for fusing together two or more components, such as welding and brazing. In the case of the rearward end  35  of manifold plenum  30 , it is particularly preferred that the means for coupling include a flanged connector  41 , as shown in  FIGS. 2 and 3 . 
     Exhaust Stack Assemblies ( 20 ). 
     Exhaust stack assembly  20 A is the forward most exhaust stack assembly, exhaust stack assembly  20 B is immediately to the rear of  20 A, exhaust stack assembly  20 C is immediately to the rear of  20 B, exhaust stack assembly  20 D is immediately to the rear of  20 C, as shown for example in  FIGS. 2 and 3 . 
     Exhaust stack assemblies  20  each comprises a leader pipe  22  and one of exhaust connectors  23 A,  23 B,  23 C and  23 D (collectively referred to as exhaust connectors  23 ). The portions of leader pipes  22  proximate the engine are joined to manifold flanges  24 . In particular, in the embodiment shown there are two manifold flanges  24 , one of which is joined to the forward two leader pipes  22  and the other of which is joined to the rearward two leader pipes  22 . Each leader pipe  22  has a centerline  25  (see  FIGS. 3 and 4 ) and has a generally circular diameter along the length of centerline  25 . 
     In the embodiment shown in  FIGS. 2 and 3 , the first exhaust connector  23 A is a curved pipe of relatively uniform diameter, whereas the diameters of second, third and fourth exhaust connectors  23 B,  23 C and  23 D increase with increasing distance from flanges  24 , in order to permit the expansion of the exhaust gases along their length. This increase in diameter is for purposes of reducing cylinder backpressure and improving exhaust gas scavenging during the exhaust cycle. 
     Manifold flanges  24  include engine-side generally planar mating surfaces  26 , which form a relatively gas-tight seal when fastened to an engine, and additionally, which define a plurality of apertures  27  that permit exhaust manifold  10  to be fastened (using nuts) to threaded studs extending from a cylinder bank of engine  700 . The portion of each stack assembly  20  distal from the engine is joined to manifold plenum  30 . 
     The engine-side mating surfaces  26  of manifold flanges  24  are oriented parallel to a plane  100 , shown in  FIGS. 2 and 4 . An engine generally will have contact surfaces machined or formed on the engine in a region circumscribing the engine exhaust ports, in order to form a relatively gas-tight seal with appropriate portions of a manifold, which in this embodiment are the engine-side mating surfaces  26  of single outlet exhaust manifold  10 . For V-8 engines, those contact surfaces generally are inclined from the vertical, for example at an angle V equal to approximately one-half the angle subtended by the cylinder banks; thus, for a V-8 engine, the angle V relative to vertical plane  104  will be for example approximately 22.5°, 30° or 36°. 
     In the present invention, it is preferred that the centerline  25  of each leader pipe  22 , as well as the centerlines of exhaust connectors  23 , be inclined upwardly at an angle α from a line  28  orthogonal to plane  100 , as shown in  FIG. 4 , so that the exhaust stack assemblies  20  lie generally in a horizontal plane when exhaust manifold  10  is joined to an engine having an inclined cylinder bank. Thus in the rear view of  FIG. 4 , the centerlines of exhaust connectors  23 , as well as centerlines  25 , collectively coincide so as to be located in that horizontal plane. In some V-8 engine cases, angle α will be approximately the same as angle V, although the ultimate choice for angle α depends on the orientation of the specific engine contact surfaces. Also, relative to arrow  920  and flanges  24  shown in  FIG. 3 , the centerline  25  of each leader pipe  22  is inclined rearwardly at an angle β from line  28  orthogonal to plane  100 . Inclining leader pipes  22  at angles α and β is for purposes of improving engine performance. 
     Leader pipes  22  are joined to flange fittings  24  via welding, brazing or by being integrally formed with manifold flanges  24 . Likewise, exhaust connectors  23  are joined to manifold plenum  30  via welding, brazing or by being integrally formed with manifold plenum  30 , and leader pipes  22  are joined to exhaust connectors  23  via welding, brazing or by being integrally formed with exhaust connectors  23 . 
     The overall width of single outlet exhaust manifold  10 , denominated W 10  in  FIG. 3 , is largely determined by the diameter of manifold plenum  30 , together with the lengths of exhaust stacks  20  (coinciding with the distance between flanges  24  and manifold plenum  30 ). It is preferred that width W 10  be as compact as exhaust gas flow, structural and service access considerations will permit, in order to yield a compact design. It is further preferred that width W 10  be the same for both single outlet exhaust manifold  10 L and single outlet exhaust manifold  10 R, so that their centerlines  29  are equidistant from the vertical plane  104  passing through the engine crankshaft centerline  701 . Centerlines  29  of exhaust manifolds  10 L and  10 R as a general matter will be located approximately in the same horizontal plane in view of their general mirror symmetry. 
     An exhaust manifold design generally corresponding to single outlet exhaust manifold  10  is described in U.S. Provisional Application No. 62/598,045 entitled “Dual-Angle Exhaust Manifold,” filed Dec. 13, 2017, the contents of which are hereby incorporated by reference as if fully set forth herein, including the aforementioned exhaust manifold design. Likewise, an exhaust manifold design generally corresponding to exhaust manifold  10  is described in U.S. patent application Ser. No. 16/168,971, entitled “Dual-Angle Exhaust Manifold,” having the same inventors as the subject application and filed on the same date as the subject application, the contents of which are hereby incorporated by reference as if fully set forth herein, including the aforementioned exhaust manifold design, found for example at paragraphs 12-20 and  FIGS. 1-3  thereof. 
     Stage 1 Reverse Installation 
     As indicated above,  FIG. 1  depicts a single outlet exhaust manifold  10  installed on engine  700  so that its rearward end  35  is proximate the rear of engine  700  and distal from the head of arrow  920 . When a Stage 1, 2 or 3 engine configuration includes a single outlet exhaust manifold  10  with this orientation, then that configuration is referred to herein as a “Standard Installation.” Thus  FIG. 1  depicts a Standard Installation of the Stage 1 configuration (which configuration has one single outlet exhaust manifold  10  on the left side of engine  700  and a second single outlet exhaust manifold  10  on the right side of engine  700 ). 
     However, in certain embodiments of the present invention, a single outlet exhaust manifold  10  is installed on engine  700  rotated 180 degrees about the vertical direction relative to the Standard Installation orientation, such that the portions that are proximate to the rear of engine  700  in the Standard Installation (furthest from the head of arrow  920 ) are instead proximate to the front of engine  700  (closest to the head of arrow  920 ). An engine configuration having such an orientation is referred to herein as a “Reverse Installation.” A Reverse Installation can have especial utility, for example, in vehicles having a rear engine design. 
     Thus in the Reverse Installation of the Stage 1 configuration, each exhaust manifold  10  is rotated 180° about the vertical direction, relative to a Standard Installation, and installed on the side of engine  700  opposite to its location in the Standard Installation, such that the rearward end  35  of manifold plenum  30  of each exhaust manifold  10  is oriented proximate to the head of arrow  920 . The Stage 1 air intake assembly  1  is the same in both a Standard Installation and a Reverse Installation of the Stage 1 configuration. 
     Stage 2 Configuration 
     In Stage 2, the engine is configured to develop substantially more power than in Stage 1. The Stage 2 configuration is depicted in  FIG. 5A . In particular, the Stage 2 configuration includes a turbocharger  160 , shown in  FIG. 5A , for transferring enthalpy from the exhaust gases to the input air by increasing intake manifold pressure. 
     The principal components first utilized in the Stage 2 configuration are the turbocharger  160 , a turbo exhaust manifold  100 , a turbocharger exhaust circuit  175 , a crossover pipe assembly  190 , and a Stage 2 turbocharger air circuit  170 , described below. 
     Turbocharger ( 160 ) 
     Turbocharger  160  extracts enthalpy from the exhaust gases and transfers it to the engine intake air by compressing that intake air. In this disclosure, a “turbocharger” is a mechanical unit that contains one or more turbines that are rotated by exhaust gases, which rotation in turn actuates a pump to compress intake air. 
     As shown in  FIGS. 11A and 11B , a preferred embodiment of turbocharger  160  includes an annular exhaust gas inlet  161  and an annular exhaust gas outlet  162 . Each of inlet  161  and outlet  162  preferably is provided with means for coupling, and more particularly with flanged connectors  176  and  177  respectively, as shown in  FIGS. 11A and 11B , to facilitate connection of turbocharger  160  with other components. Turbocharger  160  preferably includes a radial flow turbine that rotates a turbocharger shaft  163 . In the preferred embodiment shown in the figures, the exhaust gas inlet  161  is generally tangentially-oriented (i.e., generally oriented along a tangent to the circular path defined by rotation of the exhaust gas turbine blades) and the exhaust gas outlet  162  is generally axially-oriented ((i.e., generally oriented along the axis  159  of the turbine shaft  163 ). In operation, hot exhaust gas is received through exhaust gas inlet  161 . The exhaust gas then is directed to the turbine gas blades through a scroll passage  166  (shaped generally in a spiral or snail-shell configuration), which is generally orthogonal to the turbine shaft  163 . The exhaust gas passing from this scroll passage  166  causes the gas turbine blades to turn the turbocharger shaft  163 . The exhaust gas then exits through exhaust gas outlet  162 . 
     As further shown in  FIGS. 11A and 11B , turbocharger  160  includes an annular turbocharger air inlet  164  and an annular compressed air outlet  165 . Outlet  165  preferably is provided with means for coupling, and more particularly a flanged connector  178 , to facilitate connection with other components. The turbocharger air inlet  164  is generally axially-oriented (i.e., generally oriented along the axis  159  of the turbine shaft  163 ), and the compressed air outlet  165  is generally tangentially-oriented (i.e., generally oriented along a tangent to the circular path defined by rotation of the centrifugal air compressor blades). In operation, air is drawn into turbocharger air inlet  164 , preferably through an air filter  172  ( FIG. 12 ). The turbocharger shaft  163  rotates the blades/vanes of a centrifugal air compressor within the turbocharger  160 , which compresses the air. The compressed air exits through compressed air outlet  165 . A turbocharger  160  generally conforming to the foregoing design is a Garrett® GTX4202R turbocharger (available from Honeywell Turbo Technologies, Rolle, Switzerland) with a TiAL® stainless steel exhaust housing (available from TiAL Sport, Owosso, Mich.). 
     Turbo Exhaust Manifold ( 100 ) 
       FIGS. 6, 7, 9 and 10  depict a turbo exhaust manifold  100  designed in accordance with the teachings herein. Similar to single outlet exhaust manifold  10 , references herein to the “forward” or “rearward” portions of turbo exhaust manifold  100  are made with reference to the orientation of exhaust manifold  100  relative to arrow  920  depicted in  FIG. 6 . Thus in  FIG. 5A , turbo exhaust manifold  100  is installed on engine  700  so that its rearward end  135  is proximate the rear of engine  700 . 
       FIG. 6  shows the turbo exhaust manifold  100  for mounting to a cylinder bank of engine  700 . In the Stage 2 configuration, one turbo exhaust manifold  100  is utilized, and is mounted to either the left cylinder bank or the right cylinder bank of engine  700 . The turbo exhaust manifold  100  shown in  FIG. 6  is mounted in  FIG. 5A  to the left cylinder bank of engine  700 . A turbo exhaust manifold  100  for the right cylinder bank would in general design mirror turbo exhaust manifold  100  shown in  FIG. 6 . However, in the preferred embodiment of the present invention, the exhaust manifolds for the left and right cylinder banks differ in overall length, and there are other differences as well in other embodiments relating to turbo exhaust manifold  100 . Where pertinent to this disclosure, a turbo exhaust manifold  100  to be mounted on one cylinder bank will be referred to as turbo exhaust manifold  100 L and a turbo exhaust manifold for the other cylinder bank will be referred to as single outlet exhaust manifold  100 R. Where the designs features do not change depending upon which cylinder bank the turbo exhaust manifold is mounted, this disclosure will generically refer to turbo exhaust manifold  100  for convenience of reference. 
     Turbo Exhaust Manifold  100  Generally. 
     As shown for example in  FIGS. 6 and 7 , turbo exhaust manifold  100  includes a manifold plenum  130 , for collecting exhaust gases discharged from one or both cylinder banks of engine  700 , depending on the engine configuration. In the preferred embodiment, which refers for exemplary purposes to a V-8 engine, exhaust manifold  100  includes four exhaust stack assemblies  120 A,  120 B,  120 C and  120 D (collectively referred to as exhaust stack assemblies  120 ), one for each cylinder in (for purposes of example) the left cylinder bank of a V-8 engine. Exhaust stack assemblies  120  conduct exhaust gases from the cylinder bank to manifold plenum  130 . 
     Exhaust manifold  100  further includes exhaust gas routing circuit  150  for receiving exhaust gases from manifold plenum  130 . Routing circuit  150  in turn includes a turbocharger support column  152  for connection to turbocharger  160 , and exhaust gas bypass pipe  153 , for bypassing turbocharger  160 . Routing circuit  150  conducts exhaust gases from manifold plenum  130  to turbocharger exhaust gas inlet  161  via support column  152 , and to a bypass valve  186  via exhaust gas bypass pipe  153 . 
     Manifold Plenum ( 130 ). 
     Manifold plenum  130  has a generally cylindrical shape and a generally cylindrical wall, as shown in  FIGS. 6 and 8 , and is generally circular in cross-section, as shown for example in  FIG. 8 , with an axial centerline  129 . 
     As shown for example in  FIG. 7 , the diameter of manifold plenum  130  can be varied along its length; for example, the diameter of manifold plenum  130  preferably increases from the forward end  134  of plenum  130  to the rearward end  135 . This growth in diameter yields an expanding cylindrical volume from the forward end  134  to the rearward end  135 . Further, it is preferred that the rate of diameter growth of manifold plenum  130  need not be constant, but start at zero at forward end  134 , then grow at an increasing rate from forward end  134  up to approximately the mid-point between forward end  134  and rearward end  135 , then grow at a decreasing rate from that mid-point up to rearward end  135 , and again reach a zero growth rate at rear end  135 . The result of changing the growth rate in this manner is to generally give an “S” shape to the cylindrical wall of manifold plenum  130  in profile, from forward end  134  to rearward end  135 , as shown for example in  FIG. 7 . Put another way, the profile of manifold plenum  130  comes to be defined by an S-shaped curve rotated about the centerline  129  of plenum  130 . 
     The forward end  134  of manifold plenum  130  (see  FIG. 7 ) is closed off by a first exhaust stack assembly  120 A that forms a passageway between the lead cylinder of the cylinder bank and manifold plenum  130 . The rearward end  135  of manifold plenum  130  ( FIG. 6 ) defines an exhaust gas passageway  140  at its rearward terminal portion. In the Stage 2 and Stage 3 configurations of the present invention, in which exhaust manifold  100  shown in  FIG. 6  is connected to the one and only turbocharger  160  to be utilized with engine  700 , exhaust gas passageway  140  is connected to receive exhaust gases from an exhaust manifold for the right cylinder bank of the engine, to supplement the exhaust gas flow to the turbocharger, as disclosed further below (see description of Crossover Pipe Assembly ( 190 )). In the Stage 4 and 5 configurations, in which the exhaust manifold on the right cylinder bank of the engine connects to a second turbocharger  160 , exhaust gas passageway  140  can be connected to its counterpart on the right side of the engine to provide exhaust pulse balancing with the goal of improving engine torque, particularly in the lower range of engine speed. 
     The length of manifold plenum  130 , together with first exhaust stack assembly  120 A, largely determines the overall length of turbo exhaust manifold  100 . For V-configuration engines whose left and right cylinder bank discharge ports are offset (typically a consequence of utilizing crankshafts with crankpins arranged along the length of the crankshaft), it is preferred that the overall length of the turbo exhaust manifold  100  for one of the cylinder banks not be the same as the overall length of the turbo exhaust manifold  100  for the other of the cylinder banks. 
     Thus, referring to the turbo exhaust manifold  100  visible in  FIG. 5A  as  100 L, and the turbo exhaust manifold not visible in  FIG. 5A  as  100 R, it is preferred that the overall lengths of  100 L and  100 R (referred to herein as L 100 L and L 100 R; overall length L 100 L is explicitly shown in  FIG. 7 ) differ an amount equal to the offset distance between the engine&#39;s left and right cylinder bank discharge ports, so as to result in the rearward ends  135  of each manifold plenum  130  of the turbo exhaust manifolds ( 100 L and  100 R) terminating approximately on the same transverse plane (i.e., they substantively satisfy Relationship A, described in connection with single outlet exhaust manifold  10 , above). Further, this transverse plane preferably is the same transverse plane as it is preferred on which terminate the rearward ends  35  of single outlet exhaust manifolds  10 L and  10 R. For example, in the case of the LS3 model V-8 engine shown in  FIG. 5A , the left cylinder bank is offset forward of the right cylinder bank. Thus for the turbo exhaust manifold  100  visible in  FIG. 5A  and shown for example in  FIG. 6 , L 100 L will be larger than L 100 R by an amount approximately equal to the cylinder bank offset distance. 
     Exhaust Stack Assemblies ( 120 ). 
     Exhaust stack assembly  120 A is the forward most exhaust stack assembly, exhaust stack assembly  120 B is immediately to the rear of  120 A, exhaust stack assembly  120 C is immediately to the rear of  120 B, and exhaust stack assembly  120 D is immediately to the rear of  120 C, as shown for example in  FIGS. 6 and 7 . 
     Exhaust stack assemblies  120  are joined to manifold plenum  130  and channel exhaust gases from a cylinder bank (the left cylinder bank in  FIG. 5A ) into manifold plenum  130 , which collects and channels the collected gases to exhaust gas assembly routing circuit  150 . 
     Exhaust stack assemblies  120 A,  120 B,  120 C and  120 D each respectively comprises one of a leader pipe  122 A,  122 B,  122 C and  122 D (generically referred to as leader pipe  122 ) and one of exhaust connectors  123 A,  123 B,  123 C and  123 D (generically referred to as exhaust connectors  123 ). The portions of leader pipes  122  proximate the engine are joined to manifold flanges  124 . In particular, in the embodiment shown in the figures there are two manifold flanges  124 , one of which is joined to the forward two leader pipes  122 A and  122 B, and the other of which is joined to the rearward two leader pipes  122 C and  122 D. Alternative designs in accordance with the present invention include individual flanges  124  joining respective individual leader pipes  122 , as well as a single flange  124  joining all leader pipes  122 . 
     As shown in  FIGS. 6 and 7 , each of leader pipe  122 A,  122 B,  122 C and  122 D respectively has a centerline  125 A,  125 B,  125 C and  125 D (generically referred to as centerline  125 ). Centerlines  125 , as well as the centerlines of exhaust connectors  123 , preferably all are oriented to reside in the same geometrical plane  102  ( FIGS. 6 and 8 ), which in the preferred embodiment also contains centerline  129  of manifold plenum  130 . As discussed further below, plane  102  preferably is approximately horizontal in orientation when exhaust manifold  100  is joined to a conventionally mounted engine (however, centerlines  125  preferably are not parallel, as explained below). Each of leader pipes  122  has a generally circular diameter along the length of its respective centerline  125 . 
     Manifold flanges  124  include engine-side generally planar mating surfaces  126 , which form a relatively gas-tight seal when fastened to an engine, and additionally, which define a plurality of apertures  127  that permit turbo exhaust manifold  100  to be fastened (using nuts) to threaded studs extending from the cylinder bank of the engine. The portion of each of stack assemblies  120  distal from the engine is joined to manifold plenum  130 , as shown for example in  FIGS. 6 and 7 . 
     The engine-side mating surfaces of manifold flanges  124  are oriented parallel to a plane  101 , shown in  FIG. 6  and edge-on in  FIG. 8 . An engine generally will have contact surfaces machined or formed on the engine in a region circumscribing the engine exhaust ports, in order to form a relatively gas-tight seal with appropriate portions of a manifold, which in this embodiment are the engine-side mating surfaces  126  of turbo exhaust manifold  100 . For V-8 engines, those contact surfaces generally are inclined from the vertical, for example at an angle V equal to approximately one-half the angle subtended by the cylinder banks, as explained above. 
     In the present invention, it is preferred that the centerline  125  of each leader pipe  122 , as well as the centerlines of exhaust connectors  123 , be inclined upwardly at the same angle E from a line  128  orthogonal to plane  101 , as exemplified by  FIG. 8 , which depicts this relationship for leader pipe  122 D. In  FIG. 8 , the centerlines of exhaust connectors  123 , as well as centerlines  125 , collectively are contained in plane  102 . The magnitude of angle E is determined so that geometrical plane  102  containing centerlines  125 , and in turn exhaust stack assemblies  120 , are generally horizontal when exhaust manifold  100  is joined to a conventionally mounted engine having an inclined cylinder bank. In some V-8 engine cases, angle E will be approximately the same as angle V, although the ultimate choice for angle E depends on the orientation of the specific engine contact surfaces. 
     In the embodiment shown in the drawings, and particularly as shown in  FIG. 7 , it is preferred that centerlines  125  not be parallel to each other, but rather be oriented forwardly or rearwardly so as to direct leader pipes  122  at least in part toward the junction of manifold plenum  130  with exhaust gas routing circuit  150 , in order to facilitate the passage of exhaust gases to exhaust gas routing circuit  150  with reduced enthalpy loss, with the goal of improving engine performance. The amount of such forward and rearward orientation depends on the location of routing circuit  150  in manifold plenum  130 , and may be limited in magnitude in view of structural considerations. 
     In particular, relative to flanges  124  and arrow  920  shown in  FIG. 7 , leader pipes  122 A and  122 B are oriented in a rearward direction, and leader pipes  122 C and  122 D are oriented in a forward direction. Referring to  FIG. 7 , it is preferred for the embodiment depicted in the drawings, which is suitable for an LS3 model 6.2 liter displacement V-8 engine (marketed by General Motors Corp.), that centerline  125 A of leader pipe  122 A be oriented rearwardly at an angle A equal in magnitude to an angle D at which centerline  125 D of leader pipe  122 D is oriented forwardly. It is particularly preferred that centerline  125 A of leader pipe  122 A be oriented rearwardly at an angle A of 15°, and that centerline  125 D of leader pipe  122 D be oriented forwardly at an angle D of 15°. It is also particularly preferred that centerline  125 B of leader pipe  122 B be oriented rearwardly at an angle B of 10°, and that centerline  125 C of leader pipe  122 C be oriented forwardly at an angle C of 10°. 
     In the embodiment shown in the drawings, the first exhaust connector  123 A is a curved pipe of relatively uniform diameter, whereas the diameters of second, third and fourth exhaust connectors  123 B,  123 C and  123 D increase with increasing distance from flanges  124 , in order to permit the expansion of the exhaust gases along their length. This increase in diameter is for purposes of reducing cylinder backpressure and improving exhaust gas scavenging during the exhaust cycle. Leader pipes  122  are joined to flange fittings  124  via welding, brazing or by being integrally formed with flange fittings  24 . Likewise, exhaust connectors  123 A,  123 B,  123 C and  123 D are joined to manifold plenum  30  via welding, brazing or by being integrally formed with manifold plenum  130 , and leader pipes  122  are joined to exhaust connectors  123 A,  123 B,  123 C and  23 D via welding, brazing or by being integrally formed with connectors  123 A,  123 B,  123 C and  123 D. 
     The overall width of turbo exhaust manifold  100 , denominated W 100  in  FIG. 7 , is largely determined by the diameter of manifold plenum  130 , together with the lengths of exhaust stacks  120  (coinciding with the distance between flanges  124  and manifold plenum  130 ). It is preferred that width W 100  be as compact as exhaust gas flow, structural and service access considerations will permit, in order to yield a compact design. 
     It is additionally preferred that turbo exhaust manifold  100  be dimensioned so as to be generally interchangeable with single outlet exhaust manifold  10 . In particular, turbo exhaust manifold  100  preferably has approximately the same dimensions as single outlet exhaust manifold  10  in the following respects: W 100  should be about the same as W 10 ; and angle E should be about the same as angle α. As regards overall length, L 100  should be about the same as L 10  (and if Relationship A is followed for single outlet exhaust manifold  10 , so should it be for turbo exhaust manifold  100 ). 
     It is also preferred that the rearward end  135  of turbo exhaust manifold  100  include means for coupling so as to facilitate the passage of exhaust gas through exhaust passageway  140  to and from other components. It is likewise preferred that this means for coupling be the same means for coupling as is used for rearward end  35  of single outlet exhaust manifold  10 . In particular, if end  35  has a flanged connector  41 , then rearward end  135  should be provided with like means, specifically flanged connector  141  shown in  FIG. 6 . 
     Exhaust Gas Routing Circuit ( 150 ). 
     As shown in  FIGS. 6 and 8 , exhaust gas routing circuit  150  is joined to manifold plenum  130  at a junction between turbocharger support column  152  of gas routing circuit  150  and manifold plenum  130 , and exhaust gas routing circuit  150  (specifically turbocharger support column  152 ) extends from manifold plenum  130  in a generally perpendicular direction to centerline  129 . The fore-and-aft location of exhaust gas routing circuit  150  on manifold plenum  130  depends on the engine, the amount of space available, the location, size and orientation of the turbocharger and other ancillary components, and like considerations. In the preferred embodiment, which is suitable for an LS3 model 6.2 liter displacement V-8 engine, exhaust gas routing circuit  150  is located toward the forward end of manifold plenum  130  proximate to exhaust stack assembly  120 B, as shown for example in  FIG. 9 . 
     Turbocharger support column  152  in the preferred embodiment is generally circular in cross section about support column centerline  156 , depicted in  FIG. 6 . Column centerline  156  in the preferred embodiment is contained in geometrical plane  103 , which is shown in  FIG. 6  and edge-on in  FIG. 8 ; plane  103  also contains axial centerline  129  of manifold plenum  130 . The angle F subtended by plane  102  and plane  103 , shown in  FIG. 8 , preferably is determined by considerations such as locating the turbocharger as close to the engine as routing and service access considerations permit, as well as other factors pertinent to the Stage 4 configuration, discussed below in regard to  FIG. 33 . 
     In operation, exhaust gas passes from turbocharger support column  152  into turbocharger exhaust inlet  161  of turbocharger  160 . Turbocharger support column  152  preferably has a diameter, thickness and robustness sufficient to hold up and support turbocharger  160 , and resist road-induced stresses and shocks, without the need for additional supporting structures. Accordingly, in the preferred embodiment, support column  152  terminates in a means for coupling to a turbocharger  160 , and for holding turbocharger  160  rigidly in place. For example, such means for coupling preferably comprises flanged connector  154 , shown in  FIG. 6 , to which flanged connector  176  of turbocharger  160  is directly mounted with a suitable clamp or clamps, such as a V-band clamp  199 , as shown in  FIG. 12 . Such flanged connections between turbocharger exhaust inlet  161  and turbocharger support column  152  also permits the centerline  159  of turbocharger  160  to be oriented parallel to engine crankshaft centerline  701 . In the preferred embodiment, this orientation results in the flow direction through the compressed air outlet  165  generally being in a transverse plane and preferably directed approximately perpendicular to the incline of the cylinder bank of the turbo exhaust manifold  100  on which the turbocharger  160  is mounted. 
     It is desirable that the transition between manifold plenum  130  and turbocharger support column  152  be smooth and sufficiently radiused, with no sharp angles or edges, to minimize enthalpy losses associated with exhaust gas flow in the interior exhaust gas passageway to the turbocharger, and also to minimize stress crack generation. 
     Exhaust gas bypass pipe  153  in the preferred embodiment is generally circular in cross section about its axial centerline  157 , depicted in  FIG. 6  and end-on in  FIG. 8 . It is preferred that exhaust gas bypass pipe  153  be oriented in a generally perpendicular direction from and be secured to support column  152  at a junction forming a T-connection, as shown for example in  FIG. 9 . The location of bypass pipe  153  on support column  152  is determined based upon such factors as connection routing, service access, and cooperation with related components. In the preferred embodiment shown, exhaust gas bypass pipe  153  is rearwardly oriented, as shown for example in  FIGS. 6 and 9 , and the axial centerline  157  of exhaust gas bypass pipe  153  will be generally parallel to the crankshaft centerline  701  of engine  700 . In one embodiment, the axial centerline  157  of exhaust gas bypass pipe  153  can be located in plane  103 . In an alternate embodiment, the axial centerline  157  of exhaust gas bypass pipe  153  can be parallel to and offset from plane  103  a distance OF, as shown in  FIGS. 8 and 10 . The distance OF is determined by considerations such as locating the turbocharger as close to the engine as routing and service access considerations permit, as well as other factors pertinent to the Stage 4 configuration, discussed below in regard to  FIG. 33 . The design, location and orientation of exhaust gas bypass pipe  153 , as shown in the figures and as described herein, provides a compact inline, three-tiered nested configuration consisting of the turbocharger  160 , the bypass valve  186 , and the manifold plenum  130 . 
     In  FIG. 6 , exhaust gas bypass pipe  153  terminates in a bypass outlet  151  having means for coupling to an exhaust bypass valve  186 . For example, such means for coupling preferably is a flanged connector  155 , which is directly mounted to an exhaust bypass valve  186  with a suitable clamp or clamps, such as a V-band clamp  199 . The provision of exhaust gas bypass pipe  153  yields a number of engine configuration options, such as for example more easily permitting use of different types and/or models of bypass valves over time, or locating the bypass valve remotely from the turbocharger, in accordance with preference. Should a turbocharger with an integral bypass be utilized, mount  155  can be capped and sealed off. 
     Turbocharger support column  152  of exhaust gas routing circuit  150  can be joined to manifold plenum  130  via welding, brazing or by being integrally formed with manifold plenum  130 . Exhaust gas bypass pipe  153  of exhaust gas routing circuit  150  can be joined to turbocharger support column  152  in like manner. It is preferred that exhaust gas routing circuit  150  be integrally formed with manifold plenum  130 , as by casting. 
     An exhaust manifold design generally corresponding to exhaust manifold  100  is described in U.S. Provisional Application No. 62/678,460 entitled “Turbo Exhaust Manifold with Turbine Bypass Outlet,” filed May 31, 2018, the contents of which are hereby incorporated by reference as if fully set forth herein, including the aforementioned exhaust manifold design. Likewise, an exhaust manifold design generally corresponding to turbo exhaust manifold  100  is described in U.S. patent application Ser. No. 16/168,999, entitled “Turbo Exhaust Manifold with Turbine Bypass Outlet,” having the same inventors as the subject application and filed on the same date as the subject application, the contents of which are hereby incorporated by reference as if fully set forth herein, including the aforementioned exhaust manifold design, found for example at paragraphs 14-48 and  FIGS. 1-5  thereof. 
     Turbocharger Exhaust Circuit ( 175 ) 
     Turbocharger exhaust circuit  175  features the components for regulating the supply of hot exhaust gases to turbocharger  160 . As shown in  FIG. 12 , turbocharger exhaust circuit  175  includes an exhaust tee  180  and a bypass valve  186  as its principal components. 
       FIG. 12  shows the exhaust tee  180 , which includes a first tubular section  181  having an annular spent exhaust inlet  182  at one end and an annular discharge outlet  183  at the other end. Exhaust tee  180  additionally includes a second tubular section  184  connected to and defining a communicating connection with the first tubular section  181  at one end, and an annular bypassed exhaust inlet  185  at its second end. The second tubular section  184  is generally perpendicular to the first tubular section  181 . The turbocharger exhaust gas outlet  162  is connected to the spent exhaust inlet  182  of exhaust tee  180 . Inlet  182  is provided with means for coupling to turbocharger exhaust outlet  161 , preferably a flanged connector  179 , which is secured to flanged connector  177  of exhaust gas outlet  162  with a V-band clamp  199 . 
     As shown in  FIG. 12 , bypass valve  186  has an annular bypass valve inlet  187  and an annular bypass valve outlet  188  oriented at a generally right angle and connected to the bypass valve inlet  187 . Bypass valve inlet  187  is provided with means for coupling to exhaust gas bypass pipe  153 , preferably a flanged connector  195 , which is secured to flanged connector  155  of bypass outlet  151  with a V-band clamp  199 . The bypass valve outlet  188  of the bypass valve  186  is connected to the bypass valve inlet  185  of the exhaust tee  180 . Bypass valve outlet  188  of bypass valve  186 , and bypass valve inlet  185  of exhaust tee  180 , are each provided with means for coupling to the other, preferably a flanged connector  197  for inlet  185  and a flanged connector  196  for outlet  188 , which are secured together with a V-band clamp  199 . 
     The bypass valve  186  includes a spring-loaded relief valve that opens and closes a gas passageway between the bypass pipe inlet and the bypass outlet. The bypass valve  186  is used to regulate the control of exhaust gas through the turbocharger  160 , and thereby control the boost pressure of the intake air. In normal operation, bypass valve  186  is in a closed condition, preventing substantially any exhaust gas flowing from exhaust gas bypass pipe  153  into exhaust tee  180 . In such a state, substantially all exhaust gases from turbocharger exhaust manifold  100  flow through turbocharger support column  152  and into turbocharger  160  to power the air compressor of turbocharger  160 . However, in certain situations, such as when the throttle valve assembly  702  is rapidly closed, the pressure within turbocharger exhaust manifold  100  can exceed the preset level of bypass valve  186 . That excess pressure opens bypass valve  186 , which causes a certain amount of exhaust gas to flow from exhaust gas bypass pipe  153  into exhaust tee  180 , where it mixes with the spent exhaust gas from the turbocharger  160  for discharge into the atmosphere, either directly or through other components, such as noise reduction and/or pollution control components. 
     The design and arrangement of turbocharger exhaust circuit  175  in accordance with the preferred embodiment disclosed herein yields an efficient arrangement, with short connections between operative components and a compact overall package, with turbocharger  160  closely mounted to the engine and with exhaust tee  180  and bypass valve  186  located in the space between turbocharger  160  and the engine. 
     Stage 2 Turbocharger Air Circuit ( 170 ) 
     The Stage 2 turbocharger air circuit  170  features the components for supply compressed air from turbocharger  160  to engine intake manifold  710 . 
     Referring to  FIGS. 5A and 5B , the Stage 2 turbocharger air circuit  170  includes a Stage 2 air intake  180 . Stage 2 air intake  180  comprises a curved pipe shaped to connect, at a first end, the Stage 2 air intake  180  to air intake connector  5 , preferably with a T-bolt clamp  8 , and to connect, at a second end, the Stage 2 air intake  180  to turbocharger compressed air outlet  165 . The second end of Stage 2 air intake  180  is provided with means for coupling to compressed air outlet  165  of turbocharger  160 , preferably a flanged connector (not visible) that is secured to flanged connector  178  of turbocharger  160  with a V-band clamp  199 , visible in  FIG. 5B . Between these first and second ends, Stage 2 air intake  180  is contoured to pass closely proximate the engine while being smoothly contoured, as shown in  FIG. 5A . 
     Stage 2 air intake  180  includes a cylindrical connector  174  that defines an aperture  189  adapted to receive a blow-off valve  173 , which is a spring-loaded cylindrical valve that will vent compressed air to the atmosphere above a selected pre-set pressure. The aperture for blow-off valve  173  is preferably positioned on Stage 2 air intake  180  so that the axis of valve  173  is oriented generally parallel to the axis  159  of turbocharger  160 , to yield a more compact arrangement of components. 
     Crossover Pipe Assembly ( 190 ) 
     The function of crossover pipe assembly  190  in the Stage 2 configuration is to provide a passageway for the movement of exhaust gases from the single outlet exhaust manifold  10  to the turbo exhaust manifold  100 . Referring to  FIGS. 5A and 5B , crossover pipe assembly  190  includes two pipe elbows  191  connected by an intermediate piping assembly  193 . Intermediate piping assembly  193  optionally includes a bellows joint  194  to lessen stresses that may arise from installation or operation. 
     The bend radii of the pipe elbows  191  preferably are the minimal approximate value that yields acceptably low risk of crack propagation during operation, so as result in the intermediate connecting pipe assembly  190  passing in close proximity to the engine  700 , as illustrated in  FIG. 5B . 
     The two pipe elbows  191  each terminate in a means for coupling. It is preferred that this means for coupling be the same means for coupling as is used for rearward end  35  of single outlet exhaust manifold  10  and rearward end  135  of turbo exhaust  100  to facilitate their connection. In particular, if end  35  has a flanged connector  41 , and if end  135  has a flanged connector  141 , then the terminal portion of each of the two pipe elbows  191  preferably is provided with a flanged connector  192 . Furthermore, the flanged connectors  192  preferably have approximately the same dimensions as flanged connector  41  of single outlet exhaust manifold  10  and flanged connector  141  of turbo exhaust manifold  100 . 
     Where the foregoing preferences are followed, the crossover pipe assembly  190  can be readily connected, using V-band clamps  199 , to single outlet exhaust manifold  10  and/or turbo exhaust manifold  100  in any of the following three different connection configurations: crossover pipe assembly  190  connecting a left single outlet exhaust manifold  10 L to a right turbo exhaust manifold  100 R, crossover pipe assembly  190  connecting a left turbo exhaust manifold  100 L connected to a right single outlet exhaust manifold  10 R, and crossover pipe assembly  190  connecting a left turbo exhaust manifold  100 L to a right turbo exhaust manifold  100 R. 
     Stage 2 Configuration Design Preferences for Manifolds ( 10 ,  100 ) 
     As a general matter, it is preferred that the lengths L 100 L and/or L 100 R of turbo exhaust manifold  100  be selected so that, when taken in conjunction with the dimensions of pipe elbows  191 , the crossover pipe assembly  190  clears the perimeter of engine  700  to which it will be proximate (in either a Standard Installation or a Reverse Installation), yet does not extend substantially beyond that perimeter of the end of the engine to which it will be proximate, so as to yield a compact installation package. Correspondingly, where it is desired to use a single outlet exhaust manifold  10  with a turbo exhaust manifold  100  in a Stage 2 configuration (and/or in a Stage 3 configuration as well), it is generally preferred that the length L 10 L or L 10 R be selected so that, when taken in conjunction with the dimensions of pipe elbows  191 , the crossover pipe assembly  190  clears the perimeter of engine  700  to which it will be proximate (in either a Standard Installation or a Reverse Installation), yet does not extend substantially beyond that perimeter of the end of the engine to which it will be proximate, so as to yield a compact installation package. 
     Stage 2 Reverse Installation 
       FIGS. 5A and 5B  depict turbo exhaust manifold  100  installed on engine  700  so that its rearward end  135  is proximate the rear of engine  700 . When a Stage 2, 3, 4 or 5 engine configuration includes a turbo exhaust manifold  100  with this orientation, then that configuration is referred to herein as a “Standard Installation.” However, in certain embodiments of the present invention, a turbo exhaust manifold  100  (and components connected to it) are installed on engine  700  rotated 180 degrees about the vertical direction relative to the Standard Installation orientation, such that the portions that are proximate the rear of engine  700  in the Standard Installation (furthest from the head of arrow  920 ) are instead proximate the front of engine  700  (closest to the head of arrow  920 ). Engine configurations having such orientations are referred to herein as a “Reverse Installation.” 
     A Reverse Installation of the Stage 2 configuration is shown in  FIG. 5C . In particular, the single outlet exhaust manifold  10 , which is located on the right side of engine  700  in the Standard Installation shown in  FIG. 5A , is rotated 180 degrees from the Standard Installation and installed on the left side of engine  700 , as shown in  FIG. 5C . In turn, turbo exhaust manifold  100 , together with turbocharger  160  and turbocharger exhaust circuit  175 , which are located on the left side of engine  700  in the Standard Installation shown in  FIG. 5A , are rotated 180 degrees from the Standard Installation, with turbo exhaust manifold  100  being installed on the right side of engine  700 . 
     As shown in  FIG. 5C , the Stage 2 air intake  180  for a Reverse Installation has a different shape than in a Standard Installation, with air intake  180  oriented in substantial part in a longitudinal direction over the top of manifold  710 , in order to accommodate the differing relative positions of air inlet  6  and turbocharger compressed air outlet  165 . Otherwise, the Stage 2 air intake  180  for a Reverse Installation generally conforms to the specifications provided above in the description of Stage 2 air circuit  170 . Cylindrical connector  174  preferably is repositioned in a Reverse Installation as shown in  FIG. 5C  to minimize the height of the Stage 2 configuration and maintain a compact package. 
     In a Reverse Installation of the Stage 2 configuration, crossover pipe assembly  190  passes across the front of engine  700  (closest to arrow  920 ), as shown in  FIG. 5C . The exact shape of crossover pipe assembly  190  can differ between the Reverse Installation and the Standard Installation, in order to maintain close proximity of crossover pipe assembly  190  to the rear or front of engine  700 , while standing clear of engine appurtenances that are specific to that installation orientation. 
     Upgrading from a Stage 1 Configuration to a Stage 2 Configuration 
     An engine having the Stage 2 configuration (in either a Standard Installation or a Reverse Installation) can be obtained by replacing a relatively small number of principal components of an engine  700  having a Stage 1 configuration, and adding a relatively small number of principal components. More specifically, to yield a Stage 2 configuration, the following principal components are removed from an engine  700  having a Stage 1 configuration: the dual rams-horn air intake  2  and their air filters  4 ; and one of the single outlet exhaust manifolds  10 ; and the following principal components are added to the engine  700 : a turbo exhaust manifold  100 , a turbocharger exhaust circuit  175 , a Stage 2 air intake  180  and a crossover pipe assembly  190 . The single outlet exhaust manifold  10  can be removed from either side of the engine without preference, provided it is replaced with a turbo exhaust manifold  100  intended for the same side. For convenience of reference in the descriptions of Stage 2 above and in Stage 3 following, it is assumed that it is manifold  10 , visible in  FIG. 1  on the left-hand side of an engine  700  having a Stage 1 Standard Installation, that is removed to obtain the Stage 2 configuration. 
     Stage 3 Configuration 
     Stage 3 is an engine configuration developing even more power than in Stage 2. The Stage 3 configuration is depicted in  FIG. 13A , and includes an intercooler  300  mounted on the engine. The function of the intercooler is to cool the input air delivered by turbocharger  160 , thereby increasing the density of the air received by each cylinder in its intake stroke, which in turn increases the force on the piston during combustion to increase engine power. 
     The principal components first utilized in Stage 3 are the intercooler  300 , a single channel air inlet  320 , and an air outlet  360 , each described below. 
     Intercooler ( 300 ) 
       FIGS. 14 and 15  show an intercooler  300  in accordance with the present invention. In general, intercooler  300  in the preferred embodiment is a rectangular cuboid, with two opposing faces and four sides (in this disclosure, “rectangular” includes square shapes). In  FIG. 14 , there is a geometric plane  304 , which evenly divides intercooler  300  in one direction (referred to as the “longitudinal” direction for convenience of reference), and a geometric plane  305 , which evenly divides intercooler  300  in a second direction, perpendicular to the longitudinal direction (referred to as the “transverse” direction herein for convenience of reference). The intersection of these two planes from time to time may be referred to herein as the “vertical” direction for convenience of reference. 
     There is additionally a third geometric plane  306  (not shown), which is perpendicular to planes  304  and  305 , and may be referred to from time to time herein as the “horizontal” plane for convenience of reference. In this disclosure, the “plan” view of intercooler  300  refers to a view parallel to this horizontal geometric plane  306 . In the case where intercooler  300  is not square in plan view (i.e., where one side is longer than an adjacent side), for reference purposes in this disclosure the longer side will be deemed to lie in the longitudinal direction, and the shorter side in the transverse direction. 
     Intercooler  300  includes a heat exchanger core  301  and two rectangular mounting flange structures, namely intercooler flange assemblies  310 , one of which is secured to a first face  303  of intercooler core  301  about its periphery, and the other of which is secured to the second opposing face  308  (not visible in  FIG. 14 ) of intercooler core  301  about its periphery. Faces  303 ,  308  generally are parallel to each other. Two fittings  302  are also provided for the ingress and egress of coolant. 
     The air to be cooled flows through the intercooler  300 , entering through one face  303  or  308  of intercooler  300  and exiting through the other opposing face  303  or  308  of intercooler  300 . The coolant flows generally in a plane perpendicular to the air flow, entering intercooler core  301  through one of fittings  302 , passing between the faces  303 ,  308  of intercooler  300  to cool the air, and exiting intercooler core  301  through the other of fittings  302 . The coolant preferably is liquid, and more preferably water, with or without an additive to increase the liquid state temperature range, such as ethylene glycol. 
     The heat exchanger core  301  utilizes a plate and bar structure, shown in exploded form in  FIG. 15 . In particular, the heat exchanger core  301  has a multi-layer structure of plural air fin sections  318  interleaved with plural water fins  319 , where the individual air fins and water fins are separated by flow isolation sheets  316  interposed between them. Heat exchanger core  301  preferably is fabricated from aluminum or like material of relatively high thermal conductivity. 
     It is preferred that each of the intercooler flange assemblies  310  secured about the periphery of faces  303 ,  308  be substantially identical in design to the other. It is further preferred that each intercooler flange assembly  310  comprises two intercooler flange L-components  311 . Referring to  FIG. 15 , each intercooler flange L-component  311  is L-shaped, and preferably is identical in size and geometry to the other L-components, so that when one L-component  311  is paired with another such L-component  311 , they together form an intercooler flange assembly  310  in the form of a rectangular peripheral frame, which is joined to a face ( 303  or  308 ) of heat exchanger core  301  about its periphery. 
     The intercooler flange assemblies  310  can be fabricated from aluminum plate stock or the like, and are fastened by brazing, welding or the like to the opposing faces  303 ,  308  of a heat exchanger core  301 , about their peripheries, to form an intercooler  300 . Splitting each intercooler flange assembly  310  into two L-components  311  yields fabrication economies; i.e., multiple intercooler flange L-components  311  can be laid out, one against the other, and cut from one sheet, whereas cutting an intercooler flange assembly  310  as a one piece component leaves a large central cut-out, which may uneconomically need to be discarded. Further, any L-component  311  can be used on any of the four possible positions bounding the heat exchanger core  301 . 
     Each intercooler flange assembly  310  preferably has plural spaced-apart bolt apertures  312  for receiving threaded bolts  314 . It is additionally preferred that the bolt pattern for the intercooler flange assembly  310  affixed about the periphery of face  303  have the same bolt pattern as the intercooler flange assembly  310  affixed about the periphery of face  308 . 
     It is additionally preferred that the bolt apertures  312  be symmetrically arranged about intercooler flange assembly  310 . That is, referring to  FIG. 14 , it is preferred that the bolt pattern be symmetrically arranged to each side of longitudinal plane  304 , and additionally be symmetrically arranged to each side of transverse plane  305 . With these symmetric relationships, if the intercooler has a rectangular configuration, the bolt pattern presented in plan view is the same whether the intercooler is in its original orientation, or is rotated 180 degrees, or is flipped over. Likewise, if the intercooler has a square configuration, the bolt pattern presented in plan view with symmetrically arranged bolt apertures is the same whether the intercooler is in its original orientation, or is rotated 90 degrees, or is flipped over. 
     Single Channel Air Inlet ( 320 ) 
       FIG. 16  shows a single channel air inlet  320  for delivery of compressed air from turbocharger  160  to intercooler  300 . Single channel air inlet  320  includes an air inlet pipe  321 , an air inlet plenum  322  and an air inlet flange  330 . Single channel air inlet  320  is adapted to be joined to intercooler  300  to form a unitary assembly, as described below. 
     Single channel air inlet  320  is configured to deliver air across one face ( 303  or  308 ) of intercooler  300 . In the preferred embodiment, longitudinal plane  304  in  FIG. 16  evenly divides air inlet  320  in plan view, and is approximately or exactly coplanar with longitudinal plane  304  in  FIG. 14  that evenly divides intercooler  300 . The intercooler  300 /single channel air inlet  320  assembly in the preferred embodiment is particularly adapted to be positioned and mounted over the intake manifold  710  of engine  700 , with longitudinal plane  304  being approximately or exactly coplanar with longitudinal plane  104  shown in  FIG. 1 . For this mounting position, it is preferred that air inlet  320  be configured so that longitudinal plane  304  does not evenly divide inlet pipe  321 ; rather, as shown for example in  FIG. 20 , inlet pipe  321  is positioned to one side of longitudinal plane  304  (shown on edge in  FIG. 20 ). Such side positioning allows inlet pipe  321  to be closer to compressed air outlet  165  of turbocharger  160 , thereby yielding a tighter and more compact engine accessory package. For the same reason, the centerline of inlet pipe  321  is generally transversely oriented, so that its inlet aperture  337  is positioned to one side of air inlet  320 . Air flows in a generally transverse direction through inlet pipe  321  into plenum  322 . 
     Plenum  322  is internally contoured to transition the transverse air flow from inlet pipe  321  to flow across the receiving face ( 303  or  308 ) of intercooler  300 . Plenum  322  comprises four sidewalls (two longitudinal sidewalls  323 , two transverse sidewalls  326 ), which are joined by a glacis  325 . Sidewalls  323 ,  326  and glacis  325  together define an inlet plenum cavity  328  whose transverse cross-sectional area is greatest proximate to inlet pipe  321 , least distal from inlet pipe  321 , and which smoothly decreases between these two regions, as can be seen from  FIGS. 16, 17 and 18 . The transverse cross-section of inlet plenum cavity  328  at any longitudinal point is generally not symmetric about longitudinal plane  304 , as is exemplified by  FIGS. 17 and 18 , but rather is shaped with the goal of inducing the air to be distributed across the receiving face ( 303  or  308 ) of intercooler  300  more evenly, minimizing or even eliminating areas of low air flow through the receiving face, while at the same time accommodating the particular shape and positioning of inlet pipe  321  and more generally maintaining the intercooler  300 /single channel air inlet  320  assembly as a compact package. In general, plenum cavity is deeper adjacent inlet pipe  321  than distal from inlet pipe  321 . 
     It is preferred that air inlet flange  330  of single channel air inlet  320  be substantially identical in size and geometry to intercooler flange assembly  310 , and have the same pattern of bolt apertures as intercooler flange assembly  310 . Accordingly, air inlet flange  330  can be bolted to either of the two intercooler flange assemblies  310  of an intercooler  300 . 
     There is optionally provided an inlet seal assembly  331  to facilitate securing air inlet  320  to intercooler  300 . It is particularly preferred that inlet seal assembly  331  includes two inlet seal L-components  335 . As shown in  FIG. 19 , each inlet seal L-component  335  is L-shaped, and preferably is identical in size and geometry to the other inlet seal L-component  335 , so that when one such L-component  335  is paired with another such L-component  335  (arrows  338  in  FIG. 19 ), they together form an inlet seal assembly  331  in the form of a rectangular frame. Splitting the inlet seal assembly  331  into L-shaped components  335  yields fabrication economies, as described above in regard to intercooler flange assembly  310  and intercooler flange L-components  311 . Inlet seal assembly  331  preferably has the same pattern of bolt apertures as both intercooler flange assembly  310  and air inlet flange  330 . 
     Single channel air inlet  320  can be fabricated from sheet metal, such as steel or aluminum, either from a single piece of stock or from multiple pieces then assembled and fastened together, such as by riveting, brazing or welding. Alternatively, air inlet  320  can be fabricated from plastics such as HDPE, or from composite materials such as temperature-resistant fiberglass/fiberglass resin, carbon fiber, Kevlar and others. The inlet seal L-components  335  are preferably fabricated from aluminum plate stock or the like. 
     With reference to  FIG. 25 , the preferred embodiments of intercooler  300  and single channel air inlet  320  are assembled by positioning air inlet flange  330  between an inlet seal assembly  331  and one of the two intercooler flange assemblies  310  of intercooler  300 ; following which inlet seal assembly  331  and the selected intercooler flange assembly  310  are urged together, such as by means of nuts  309  and bolts  314 , to yield a unitary air inlet/intercooler system. Inlet seal assembly  331  distributes the compressive joinder loads around the periphery of air inlet flange  330  to provide a better seal than would be attained by using bolts alone creating pressure points at discrete locations along air inlet flange  330 . A resilient sealing gasket, component or structure may additionally be interposed between air inlet flange  330  and intercooler flange assembly  310  to contribute to sealing. For example,  FIG. 14  shows an optionally provided sealing groove  317  on the exterior face of each intercooler flange assembly  310  for receiving an O-ring  307  and yielding a relatively air-tight seal between intercooler  300  and air inlet  320 . 
     Air Outlet ( 360 ) 
       FIG. 21  shows an air outlet  360  for delivery of cooled compressed air from intercooler  300  to intake manifold  710  of engine  700 . Air outlet  360  includes an air outlet pipe  361 , an air outlet plenum  362  and an air outlet flange  363 . In the embodiment of  FIGS. 21-23 , air outlet plenum  362  includes two cylindrical connectors  366 , each defining an aperture  367 . Air outlet  360  is adapted to be joined to intercooler  300  to form a unitary assembly, as described below. 
     Air outlet  360  is configured to receive air issuing from one face ( 303  or  308 ) of intercooler  300 . In the preferred embodiment, longitudinal plane  304  in  FIG. 21  evenly divides air outlet pipe  361 , and is coplanar with longitudinal plane  304  in  FIG. 14  that evenly divides intercooler  300 . The intercooler  300 /air outlet  360  assembly in the preferred embodiment is particularly adapted to be mounted over intake manifold  710  engine  700 , with longitudinal plane  304  passing through the crankshaft axis  701  (coincident with longitudinal plane  104  in  FIG. 1 ). In this orientation, air outlet plenum  362  is internally contoured to transition the air issuing from one of the faces ( 303  or  308 ) of intercooler  300  into air outlet pipe  361 , to be routed to engine intake manifold  710 . The centerline of the outlet aperture  371  of air outlet pipe  361  in the preferred embodiment preferably resides in longitudinal plane  304  and is oriented in the vertical direction. The mouth of outlet aperture  371  is oriented in a horizontal plane  306 . These design features provide a compact connection to engine intake manifold  710 . There is a bend in air outlet pipe  361  to redirect air received from plenum  362  to outlet  371 . 
     Air outlet plenum  362  comprises four sidewalls (two longitudinal sidewalls  373 , two transverse sidewalls  376 ) joined by a carapace  375 . Sidewalls  373 ,  376  and carapace  375  together define an outlet plenum cavity  378  whose transverse cross-sectional area is greatest proximate to air outlet pipe  361 , least distal from air outlet pipe  361 , and which smoothly decreases between these two regions, as can be seen from  FIGS. 21, 22 and 23 . The transverse cross-section of outlet plenum cavity  378  is generally symmetric about longitudinal plane  304 , as shown in  FIGS. 22 and 23 . 
     Connectors  366 , shown in  FIG. 21 , are adapted to be coupled to two blow-off valves  173  to be received in apertures  367 . The provision of two connectors  366  permit the use of two blow-off valves  173  for increased air flow. Either or both can be capped if not utilized. 
     It is preferred that air outlet flange  363  be identical in size and geometry to intercooler flange assembly  310 , and have the same pattern of bolt apertures as intercooler flange assembly  310 . Accordingly, air outlet flange  363  can be bolted to either of the two intercooler flange assemblies  310  of an intercooler  300 . 
     There is optionally provided an outlet seal assembly  364  to facilitate securing air outlet  360  to intercooler  300 . It is particularly preferred that each outlet seal assembly  364  includes two outlet seal L-components  365 . As shown in  FIG. 24 , each outlet seal L-component  365  is L-shaped, and preferably is identical in size and geometry to the other outlet seal L-component  365 , so that when one such L-component  365  is paired with another such L-component  365  (arrows  339  in  FIG. 24 ), they together form an outlet seal assembly  364  in the form of a rectangular frame. Splitting the outlet seal assembly  364  into L-components  365  yields fabrication economies, as described above in regard to intercooler flange assembly  310  and intercooler flange L-components  311 . Outlet seal assembly  364  preferably has the same pattern of bolt apertures as intercooler flange assemblies  310  and air outlet flange  363 . 
     Air outlet  360  can be fabricated from sheet metal, such as steel or aluminum, either from a single piece of stock or from multiple pieces, and then assembled and fastened together, such as by riveting, brazing or welding. Alternatively, air outlet  360  can be fabricated from plastics such as HDPE, or from composite materials such as temperature-resistant fiberglass/fiberglass resin, carbon fiber, Kevlar and others. The outlet seal L-components  365  preferably are fabricated from aluminum plate stock or the like. 
       FIG. 25  depicts the assembly of the preferred embodiments of air outlet  360  and intercooler  300 . In particular, air outlet flange  363  is positioned between an outlet seal assembly  364  and one of the two intercooler flange assemblies  310 ; following which outlet seal assembly  364  and the selected intercooler flange assembly  310  are urged together, such as by means of nuts  309  and bolts  314 , to yield a unitary air outlet/intercooler system. A resilient sealing gasket, component or structure may additionally be interposed between air outlet flange  363  and intercooler flange assembly  310  to contribute to sealing. For example,  FIG. 14  shows an optionally provided sealing groove  317  on the exterior face of each intercooler flange assembly  310  for receiving an O-ring  307  and yielding a relatively air-tight seal between intercooler  300  and air outlet  360 . 
     It is preferred that the single channel air inlet  320 /intercooler  300 /air outlet  360  assembly be positioned and mounted over the air intake manifold  710  of engine  700 , between the cylinder banks of engine  700  as discussed above, and held in place by two brackets, front bracket  381  and rear bracket  382 , as shown in  FIG. 13A . Brackets  381 ,  382  preferably are bent from aluminum plate and are secured with nuts and bolts to the underside of single channel air inlet  320 , below air inlet seal assembly  331 , and to the cylinder heads of engine  700  with nuts and bolts. In this position, outlet aperture  371  is positioned over throttle assembly  702 , to which it passes cooled compressed air by way of air intake connector  5 . Air intake connector  5  is secured at one end to throttle assembly  702  with a T-bolt clamp  8 , and is secured at a second end to air outlet pipe  361  with a T-bolt clamp  8 . Air intake connector  5  in the Stage 3 configuration is longer than in the Stage 1 configuration and the Stage 2 configuration, so as to accommodate the height of the single channel air inlet  320 /intercooler  300 /air outlet  360  assembly. 
     A single channel air inlet, an intercooler and an air outlet generally corresponding in design respectively to single channel air inlet  320 , intercooler  300  and air outlet  360  are described in U.S. Provisional Application No. 62/687,461 entitled “Intercooler and Intercooler Systems,” filed Jun. 20, 2018. The contents of U.S. Provisional Application No. 62/687,461 are hereby incorporated by reference as if fully set forth herein, including the aforementioned single channel air inlet, intercooler and air outlet designs, found for example at paragraphs 28-44, 53-60, 62 and FIGS. 1A-2E, 4A-4D and 5A-5B thereof, among others, of U.S. Provisional Application No. 62/687,461. 
     Stage 3 Turbocharger Air Circuit 
     The Stage 3 turbocharger air circuit  380  features the components for the supply of compressed air from turbocharger  160  to air inlet pipe  321  of single channel air inlet  320 . 
     Given the location of turbocharger  160  (mounted on turbocharger support column  152  of turbo exhaust manifold  100 ) and the preferred location of single channel air inlet  320  (between the cylinder banks of engine  700  above the engine intake manifold  710 , as shown in  FIG. 13A ), the overall design elements are sufficiently compact that air inlet pipe  321  optionally includes the Stage 3 turbocharger air circuit  380  as an integral component. That is, the length and orientation of air inlet pipe  321  can be made to directly connect air inlet pipe  321  to compressed air outlet  165  of turbocharger  160 . 
     Alternatively, it is preferred to interpose a resilient connection between air inlet pipe  321  and compressed air outlet  165  of turbocharger  160 . Referring to  FIG. 26 , there is a relatively short air inlet connection hose  385 , for example HPS silicone hose, secured at a first end to air inlet pipe  321  using a T-bolt hose clamp  8 , and secured at a second end to a flanged adaptor  384  using a T-bolt hose clamp  8 . The flanged portion  398  of adaptor  384  in turn is secured to flanged connector  178  of turbocharger  160  using a V-clamp  199 . 
     To allow the engine to better function with the volume of air made available in the Stage 3 configuration (and also in the Stages 4 and 5 configurations), it is preferred to utilize pistons that increase the cylinder volume at top dead center, such as by substituting pistons with reduced crown height. 
     Stage 3 Reverse Installation 
       FIG. 13A  depicts a Standard Installation of the Stage 3 configuration (which has one single outlet exhaust manifold  10  and one turbo exhaust manifold  100 ). However, in another embodiment, the Stage 3 configuration can be in a Reverse Installation, as shown in  FIG. 13B . In particular, the exhaust manifold  10  is rotated 180 degrees from the Standard Installation and installed on the left side of engine  700 , and turbo exhaust manifold  100 , together with turbocharger  160  and turbocharger exhaust circuit  175 , are rotated 180 degrees from the Standard Installation, with turbo exhaust manifold  100  being installed on the right side of engine  700 . 
     In a Reverse Installation of the Stage 3 configuration, the crossover pipe assembly  190  passes across the front of engine  700  (closest to arrow  920 ), as show in  FIG. 13B . As in the case of a Reverse Installation of the Stage 2 configuration, the exact shape of crossover pipe assembly  190  can differ in the Stage 3 configuration between the Reverse Installation and the Standard Installation, in order to maintain close proximity of crossover pipe assembly  190  to the rear or front of engine  700 , while standing clear of engine appurtenances that are specific to that installation orientation. 
     On the other hand, air outlet  360  in accordance with the preferred embodiment utilizes the same orientation (air outlet pipe  361  toward the front of the engine, positioned over air intake elbow  6 ) in both a Standard Installation and a Reverse Installation of a Stage 3 configuration. The preferred symmetric arrangement of the bolt pattern of intercooler flange assembly  310  and air inlet flange  350  permits installation of a single channel air inlet  320 /intercooler  300 /air outlet  360  assembly in either a Standard Installation or a Reverse Installation without the need for employing different components for each. 
     Upgrading from a Stage 2 Configuration to a Stage 3 Configuration 
     An engine having the Stage 3 configuration (in either a Standard Installation or a Reverse Installation) can be obtained by replacing a relatively small number of principal components of an engine having a Stage 2 configuration, and adding a relatively small number of additional principal components. More specifically, to yield a Stage 3 configuration, the following component is removed from an engine having a Stage 2 configuration: Stage 2 air intake  180 ; and the following principal components are added to engine  700 : single channel air inlet  320 , intercooler  300  and air outlet  360 . Rather than being discarded, any blow-off valve  173  positioned in Stage 2 air intake  180  can be inserted into one of apertures  367  of its respective cylindrical connector  366 , for further utilization in the Stage 3 configuration. The function of crossover pipe assembly  190  in the Stage 3 configuration is that same as in the Stage 2 configuration: to provide a passageway for the movement of exhaust gases from the single outlet exhaust manifold  10  to the turbo exhaust manifold  100 . 
     Stage 4 Configuration 
     Stage 4 is an engine configuration developing yet more power than in Stage 3. The Stage 4 configuration is depicted in  FIG. 27A , which includes two turbochargers  160  (one more than in Stages 2 and 3), each of which feeds compressed air to intercooler  300 . The function of the additional turbocharger  160  is to further increase the amount of enthalpy extracted from the exhaust gases to deliver an even larger charge of air to the engine cylinders during the intake stroke. The function of the crossover pipe assembly  190  in the Stage 4 configuration is to provide exhaust pressure communication between the two turbo exhaust manifolds  100 . 
     The principal components first utilized in the Stage 4 configuration are a second turbocharger  160 , substantially as first described above in connection with the Stage 2 configuration, and a dual channel air inlet  340 , described below, in place of single channel air inlet  320 . Stage 4 additionally utilizes a second turbo exhaust manifold  100 , plus a second turbocharger exhaust gas circuit  175 , both previously described in connection with the Stage 2 configuration. The dimensions of certain aspects of this second turbo exhaust manifold  100  may differ from the comparable dimensions of its counterpart for the other engine cylinder bank, depending upon the turbocharger configuration, as explained below. Given the volume of the compressed air flow generated in the Stage 4 configuration, it is preferred to utilize two blow-off valves  173 , which are received in each of the two apertures  367  of cylindrical connectors  366  in air outlet  360 , as shown for example in  FIG. 27A . 
     Dual Channel Air Inlet ( 340 ) 
       FIG. 28  shows a dual channel air inlet  340  for delivery of compressed air through two channels, conduits or pipes, from two turbochargers  160  to intercooler  300 . In comparison with single channel air inlet  320 , dual channel air inlet  340  is characterized by having two plenums. Accordingly, referring to  FIGS. 28, 31 and 32 , dual channel air inlet  340  includes a first air inlet pipe  341 A, a second air inlet pipe  341 B, a first air inlet plenum  342 A, a second air inlet plenum  342 B and an air inlet flange  350 . Dual channel air inlet  340  is adapted to be joined to intercooler  300  to form a unitary assembly, as described below. 
     Dual channel air inlet  340  is configured to deliver air across one face ( 303  or  308 ) of intercooler  300 . In the preferred embodiment, longitudinal plane  304  in  FIG. 28  evenly divides air inlet  340  in plan view, and is coplanar with longitudinal plane  304  in  FIG. 14  that evenly divides intercooler  300 . The intercooler  300 /dual channel air inlet  340  assembly in the preferred embodiment is particularly adapted to be positioned and mounted over intake manifold  710  of engine  700 , with longitudinal plane  304  being exactly or approximately coplanar with longitudinal plane  104  shown in  FIG. 1 . For this mounting position, it is preferred that dual channel air inlet  340  be configured so that longitudinal plane  304  does not pass through either inlet pipe  341 A or  341 B; rather, as shown in  FIG. 32  inlet pipes  341 A and  341 B preferably are each positioned to one side of longitudinal plane  304  (shown on edge in  FIG. 32 ), one to one side and the other to the other side. Such side positioning allows each of inlet pipes  341 A and  341 B to be closer, in an appropriately configured system, to a corresponding air compressor air outlet, thereby yielding a tighter and more compact engine accessory package. For the same reason, the centerline of each of inlet pipes  341 A and  341 B is generally transversely oriented, so that its respective inlet aperture,  357 A,  357 B, is to one side of air inlet  340 , and so as to receive and route air flow in a generally transverse direction into air inlet plenum  342 A and  342 B respectively. 
     The shapes of inlet pipes  341 A and  341 B may or may not be the same, in accordance with other engine system aspects. For example, in the case where the associated connecting systems are symmetric about longitudinal plane  304 , inlet pipes  341 A and  341 B can have the same shapes. However, some turbochargers, such as for example turbocharger  160  depicted in  FIGS. 11A and 11B , are asymmetrical in shape. The connection of dual channel air inlet  340  with such turbochargers can differ in location and orientation, depending on to which side of longitudinal plane  304  the connection is being made. To accommodate those cases, inlet pipes  341 A and  341 B can differ in shape, as shown in  FIG. 32 , so as to compactly connect to a corresponding turbocharger. 
     In the preferred embodiment shown in  FIGS. 28-32 , air inlet pipe  341 A delivers air to air inlet plenum  342 A, and air inlet pipe  341 B delivers air to air inlet plenum  342 B; the inlet plenums  342 A and  342 B are substantially independent. As an alternative embodiment, one large plenum  342  can be utilized instead. Each plenum  342 A and  342 B in the preferred embodiment is internally contoured to transition the transverse air flow from inlet pipes  341 A and  341 B respectively to flow across the receiving face ( 303  or  308 ) of intercooler  300 . Plenum  342 A comprises four sidewalls (two longitudinal sidewalls  343 A, two transverse sidewalls  346 A), which are joined by a glacis  345 A (see  FIG. 29 ), and plenum  342 B comprises four sidewalls (two longitudinal sidewalls  343 B, two transverse sidewalls  346 B), which are joined by a glacis  345 B ( FIG. 29 ). 
     Sidewalls  343 A,  346 A and glacis  345 A together define a first inlet plenum cavity  348 A whose transverse cross-sectional area is greatest proximate to inlet pipe  341 A, least distal from inlet pipe  341 A, and which generally decreases between these two regions in a smooth manner, as shown in  FIGS. 28, 29, 30 and 31 . Likewise, sidewalls  343 B,  346 B and glacis  345 B together define a second inlet plenum cavity  348 B whose transverse cross-sectional area is greatest proximate to inlet pipe  341 B, least distal from inlet pipe  341 B, and which generally decreases between these two regions in a smooth manner, as shown in  FIGS. 28, 29, 30 and 31 . The transverse cross-section of each of inlet plenum cavities  348 A and  348 B at any longitudinal point in the preferred embodiment will have a shape that in general will depart from symmetry, as is exemplified by  FIGS. 29 and 30 , since each cavity is shaped with the goal of inducing the air to be distributed across the receiving face ( 303  or  308 ) of intercooler  300  more evenly, minimizing or even eliminating areas of low air flow through the receiving face, while at the same time accommodating the particular shape and positioning of air inlet pipe  341 A or  341 B and more generally maintaining the intercooler  300 /dual channel air inlet  340  assembly as a compact package. 
     It is preferred that air inlet flange  350  of dual channel air inlet  340  be identical in size and geometry to intercooler flange assembly  310 , and have the same pattern of bolt apertures as intercooler flange assembly  310 . Accordingly, air inlet flange  343  can be bolted to either of the two intercooler flange assemblies  310  of an intercooler  300 . Additionally, dual channel air inlet  340  can be affixed to intercooler  330  in substantially the same manner as described above in connection with single channel air inlet  330 , including utilizing the same inlet seal assembly  331 . 
     Dual channel air inlet  340  can be fabricated from sheet metal, such as steel or aluminum, either from a single piece of stock or from multiple pieces then assembled and fastened together, such as by riveting, brazing or welding. Alternatively, dual channel air inlet  340  can be fabricated from plastics such as HDPE, or from composite materials such as temperature-resistant fiberglass/fiberglass resin, carbon fiber, Kevlar and others. 
     The preferred embodiments of dual channel air inlet  340  and intercooler  300  are assembled in the same way as single channel air inlet  320 , as described in reference to the Stage 3 configuration and  FIG. 25 , with dual channel air inlet  340  being utilized in lieu of single channel air inlet  320 . The preferred positioning and mounting location of the dual channel air inlet  340 /intercooler  300 /air outlet  360  assembly is the same as the single channel air inlet  320 /intercooler  300 /air outlet  360  assembly in the Stage 3 configuration (over the air intake manifold  710  of engine  700 , between the cylinder banks of engine  700 , as described above). The dual channel air inlet  340 /intercooler  300 /air outlet  360  assembly can be held in place by the same brackets  381 ,  382 , shown in  FIG. 27A , as were employed in the Stage 3 configuration. 
     A dual channel air inlet generally corresponding in design to dual channel air inlet  340  is described in U.S. Provisional Application No. 62/687,461 entitled “Intercooler and Intercooler Systems,” filed Jun. 20, 2018. The contents of U.S. Provisional Application No. 62/687,461 are hereby incorporated by reference as if fully set forth herein, including the aforementioned dual channel air inlet design, found for example at paragraphs 45-52, 63-64 and FIGS. 3A-3E and 6-7 thereof, among others, of U.S. Provisional Application No. 62/687,461. 
     Stage 4 Turbocharger Air Circuit ( 390 ) 
     The Stage 4 turbocharger air circuit  390  features the components for the supply of compressed air from each of turbochargers  160  to a respective air inlet pipes  341 A,  341 B of dual channel air inlet  340 . 
     Given the location of turbochargers  160  (mounted on turbocharger support columns  152  of turbo exhaust manifolds  100 ) and the preferred location of dual channel air inlet  340  (between the cylinder banks of engine  700  above the engine intake manifold  710 , as shown in  FIG. 27A ), the overall design elements are sufficiently compact that air inlet pipes  341 A,  341 B optionally can include the Stage 4 turbocharger air circuit  390  as an integrated component. That is, the length and orientation of each air inlet pipe  341 A,  341 B can be made to directly connect to a respective compressed air outlet  165  of each of the turbochargers  160  utilized in the Stage 4 configuration. 
     Alternatively, optionally there is provided one or more resilient connecting components between either or both of air inlet pipes  341 A,  341 B and a respective compressed air outlet  165  of the turbochargers  160 . For example, in one embodiment it is preferred to interpose a resilient connection between air inlet pipe  341 A and compressed air outlet  165  of the turbocharger  160  mounted to turbocharger support column  152  of turbo exhaust manifold  100 L. The specific components (adaptor  384 , connecting hose  385 , T-bolt clamps  8 ) and configuration can be the same as utilized in regard to the connection with air inlet pipe  321  in the Stage 3 configuration described above and shown in  FIG. 26 . With such a coupling arrangement, air inlet pipe  341 B can be rigidly connected to the compressed air outlet  165  of the turbocharger  160  that is mounted to the turbocharger support column  152  of turbo exhaust manifold  100 R. Such a rigid connection can be realized by providing inlet aperture  357 B with a flanged connector  386  (shown in  FIGS. 28 and 32 ), which is secured to flanged connector  178  of compressed air outlet  165  of such turbocharger  160 , with a V-band clamp  199 . 
     The air outlet  360  in the Stage 4 configuration can be connected to the throttle assembly  702  in the same manner, and using the same components, as described above for the Stage 3 configuration. 
     Stage 4 Configuration Turbo Exhaust Manifold Design Preferences ( 100 L,  100 R) 
     In the type of turbocharger  160  depicted in  FIGS. 11A and 11B , the exhaust gas passes to the turbine wheel through a turbine scroll passage  166 . Correspondingly, there is an air compressor turbine scroll passage  167  that delivers compressed air to the turbocharger compressed air outlet  165 . The shapes of these scroll passages generally result in turbocharger  160  being radially asymmetric about turbocharger axis  159  (non-axisymmetric). Since a Stage 4 configuration utilizes two turbochargers  160 , certain positional differences in the transverse plane may arise from the turbocharger asymmetries. These differences are accommodated by the present invention in one of two ways. 
     First, in one embodiment of the present invention, it is preferred that the two turbochargers  160  utilized in the Stage 4 configuration rotate in opposite directions, and that their air and exhaust gas intake and outlet components are mirrored in design. For this embodiment, the overall arrangement of exhaust manifolds  100 L and  100 R and their associated turbochargers  160  will be symmetric about the longitudinal plane  104  of engine  700 , notwithstanding that the turbochargers  160  are themselves asymmetric, as described above. 
     In another embodiment of the present invention, the same design of turbocharger  160  (each rotating in the same direction) is used with exhaust manifolds  100 L and  100 R. For this embodiment, the values of angle F and offset OF are not the same for exhaust manifolds  100 L and  100 R, but rather differ. This embodiment is depicted in  FIG. 33 , which shows exhaust manifolds  100 L and  100 R connected to a schematically depicted engine  700 , divided by vertical plane  104 . Among other things,  FIG. 33  shows a turbocharger  160 L mounted on circular mount  154  of exhaust manifold  100 L, and a turbocharger  160 R mounted on circular mount  154  of exhaust manifold  100 R, with the centerlines  159  of turbochargers  160 L,  160 R oriented generally parallel to plane  104 . In this embodiment, it is preferred that the angular and dimensional relationships relating to exhaust gas routing circuit  150  be appropriately adjusted for each of exhaust manifolds  100 L and  100 R such that when turbochargers  160 L and  160 R are respectively mounted on circular mounts  154  of turbocharger support columns  152  of exhaust manifold  100 L and  100 R: the distance TCL from the centerline  159  of turbocharger  160 L to plane  104  is approximately the same as the distance TCR from the centerline  159  of turbocharger  160 R to plane  104  (“Relationship B”); and the centerline  159  of turbocharger  160 L lies in approximately the same horizontal plane as the centerline  159  of turbocharger  160 R (“Relationship C”). 
     As an example of an adjustment in angular relationships directed to realizing Relationship B, in  FIG. 33  the angle FL subtended by plane  102  and plane  103  of exhaust manifold  100 L, and the angle FR subtended by plane  102  and plane  103  of exhaust manifold  100 R, are each adjusted such that when the turbochargers  160 L and  160 R are respectively mounted on support columns  152  of exhaust manifolds  100 L and  100 R, the distance TCL from the centerline  159  of turbocharger  160 L to plane  104  is approximately the same as the distance TCR from the centerline  159  of turbocharge  160 R to plane  104 . 
     It is additionally preferred that the foregoing angular relationships and dimensions be appropriately adjusted such that: the distance RPL from the centerline  157  of bypass pipe  153  of exhaust manifold  100 L to plane  104  is approximately the same as the distance RPR from the centerline  157  of bypass pipe  153  of exhaust manifold  100 R to plane  104  (“Relationship D”); and the centerline  157  of bypass pipe  153  of exhaust manifold  100 L lie in approximately the same horizontal plane as the centerline  157  of bypass pipe  153  of exhaust manifold  100 R (“Relationship E”). 
     As an example of an adjustment in dimensional relationships directed to realizing Relationship D, in  FIG. 33  the axial centerline  157  of exhaust gas bypass pipe  153  of exhaust manifold  100 L is offset from  100 L&#39;s plane  103  a distance OFL, and the axial centerline  157  of exhaust gas bypass pipe  153  of exhaust manifold  100 R is offset from  100 R&#39;s plane  103  a distance OFR, such that the distance RPL from the centerline  157  of bypass pipe  153  of manifold  100 L to plane  104  is approximately the same as the distance RPR from the centerline  157  of bypass pipe  153  of manifold  100 R to plane  104 . 
     Otherwise, except as discussed above in connection with Relationships A-E, the components of exhaust manifolds  100 L and  100 R as relevant here mirror each other (e.g., dimensions and orientations of exhaust stack assemblies  120 , manifold plenums  130 , locations of exhaust gas routing circuits  150  on manifold plenums  130 ). These mirrored relationships can facilitate achieving these results: the distance EPL between centerline  129  of manifold plenum  130  of exhaust manifold  100 L and vertical plane  104  of engine  700  being approximately the same as the distance EPR between centerline  129  of manifold plenum  130  of exhaust manifold  100 R and vertical plane  104  of engine  700  (“Relationship F”); centerline  129  of manifold plenum  130  of exhaust manifold  100 L lying in approximately the same horizontal plane as the centerline  129  of manifold plenum  130  of exhaust manifold  100 R (“Relationship G”); centerline  156  of support column  152  of exhaust manifold  100 L lying approximately in the same transverse plane (i.e., having an orthogonal relationship with the crankshaft centerline  701 ), as the centerline  156  of support column  152  of exhaust manifold  100 R (“Relationship H”); and bypass outlet  151  of exhaust gas bypass pipe  153  of exhaust manifold  100 L lying approximately in the same vertical plane, transversely oriented to plane  104 , as the bypass outlet  151  of exhaust gas bypass pipe  153  of exhaust manifold  100 R (“Relationship I”). 
     The foregoing Relationships A-I are preferred in the embodiment shown in  FIG. 33  to augment the intercooperative nature of the components, and increase the customizable aspects of the present invention, by making easier connecting the elements of exhaust manifolds  100 L,  100 R, as well as the turbochargers  160 L and  160 R, with other components that are symmetrically arranged about vertical plane  104  and/or the vehicle centerline. In a particular embodiment as shown in  FIG. 3B  suitable for use with an LS3 model 6.2 liter displacement V-8 engine, angle FL is less than the angle FR, angle FL is about 86 degrees and angle FR is about 121.5 degrees. In addition, in the same embodiment the offset OFL is less than the offset OFR, offset OFL is about 0.22 inch and offset OFR is about 1.91 inches. 
     Stage 4 Reverse Installation 
       FIG. 27A  depicts a Standard Installation of the Stage 4 configuration (which has two turbo exhaust manifolds  100 ). However, in another embodiment, the Stage 4 configuration can be in a Reverse Installation, as shown in  FIG. 27B . In particular, each turbo exhaust manifold  100  (together with its associated turbocharger  160 , turbocharger exhaust circuit  175 , and any non-integral (i.e., additional and separate) components of Stage 4 turbocharger air circuit  390 ) and the dual channel air inlet  340  are rotated 180 degrees from the Standard Installation. 
     In a Reverse Installation of the Stage 4 configuration, the crossover pipe assembly  190  passes across the front of engine  700  (closest to arrow  920 ), as shown in  FIG. 27B . As in the case of a Reverse Installation of the Stage 2 and Stage 3 configurations, the exact shape of crossover pipe assembly  190  can differ in the Stage 4 configuration between the Reverse Installation and the Standard Installation 
     On the other hand, air outlet  360  in accordance with the preferred embodiment utilizes the same orientation (air outlet pipe  361  toward the front of the engine, positioned over air intake elbow  6 ) in both a Standard Installation and a Reverse Installation. The preferred symmetric arrangement of the bolt pattern of intercooler flange assembly  310  and air inlet flange  350  permits installation of a dual channel air inlet  340 /intercooler  300 /air outlet  360  assembly in either a Standard Installation or a Reverse Installation without the need for employing different components for each. 
     Upgrading from a Stage 3 Configuration to a Stage 4 Configuration 
     Optionally, an engine having a Stage 4 configuration (in either a Standard Installation or a Reverse Installation) can be obtained by replacing a relatively small number of principal components of an engine  700  having a Stage 3 configuration, and adding a relatively small number of additional principal components. More specifically, to yield a Stage 4 configuration, the following components are removed from an engine  700  having a Stage 3 configuration: the remaining single outlet exhaust manifold  10 , and single channel air inlet  320 ; and the following principal components are added to the engine  700 : a second turbo exhaust manifold  100  (in place of the removed single outlet exhaust manifold  10 ), a dual channel air inlet  340  (replacing the removed single channel air inlet  320 ); and a second turbocharger exhaust circuit  175 . 
     Stage 5 Configuration 
     Stage 5 is an engine configuration developing even further power than in Stage 4. The Stage 5 configuration is depicted in  FIG. 34 , which includes two intercoolers  300 , stacked vertically. The principal component first utilized in Stage 5 is a second intercooler  300 . 
     As shown in  FIG. 34 , the preferred location of the dual channel air inlet  340 /intercooler  300 /intercooler  300 /air outlet  360  assembly in the Stage 5 configuration is the same as in the Stage 4 configuration (over the air intake manifold  710  of engine  700 , between the cylinder banks of engine  700 ). In this preferred location, the dual channel air inlet  340 /intercooler  300 /intercooler  300 /air outlet  360  assembly can be held in place by the same two brackets  381 ,  382  that were used in the Stage 3 configuration and the Stage 4 configuration, as shown in  FIG. 34 . 
     A two intercooler design that generally corresponds with the utilization of the two intercoolers  300  as disclosed herein is described in U.S. Provisional Application No. 62/687,461 entitled “Intercooler and Intercooler Systems,” filed Jun. 20, 2018. The contents of U.S. Provisional Application No. 62/687,461 are hereby incorporated by reference as if fully set forth herein, including the aforementioned two intercooler design and components utilized in connection therewith, found for example at paragraphs 28-37, 45-60, 62-64, FIGS. 1A-1B, 3A-5A and 7 thereof, among others, of U.S. Provisional Application No. 62/687,461. 
     Stage 5 Reverse Installation 
       FIG. 34  depicts a Standard Installation of the Stage 5 configuration. However, in another embodiment, the Stage 5 configuration can be in a Reverse Installation. In particular, each turbo exhaust manifold  100  (together with its associated turbocharger  160 , turbocharger exhaust circuit  175 , any non-integral (i.e., additional and separate) components of Stage 4 turbocharger air circuit  390 ) and the dual channel air inlet  340  are rotated 180 degrees from the Standard Installation. 
     In a Reverse Installation, the crossover pipe assembly  190  passes across the front of engine  700  (closest to arrow  920 ). As in the case of a Reverse Installation of the Stage 2, Stage 3 and Stage 4 configurations, the exact shape of crossover pipe assembly  190  can differ in the Stage 5 configuration between the Reverse Installation and the Standard Installation 
     On the other hand, air outlet  360  in accordance with the preferred embodiment utilizes the same orientation (air outlet pipe  361  toward the front of the engine, positioned over air intake elbow  6 ) in both a Standard Installation and a Reverse Installation. The preferred symmetric arrangement of the bolt pattern of intercooler flange assembly  310  and air inlet flange  350  permits installation of a single channel air inlet  320 /intercooler  300 /intercooler  300 /air outlet  360  assembly in either a Standard Installation or a Reverse Installation without the need for employing different components for each. 
     Upgrading from a Stage 4 Configuration to a Stage 5 Configuration 
     Optionally, an engine having a Stage 5 configuration (in either a Standard Installation or a Reverse Installation) can be obtained by bolting a second intercooler  300  to a first intercooler  300  along their adjacent flange assemblies  310  between dual channel air inlet  340  and air outlet  360 . Relative to the Stage 4 configuration, a longer air intake connector  5  is utilized in the Stage 5 configuration to accommodate the additional height resulting from addition of the second intercooler  300 . The function of crossover pipe assembly  190  in the Stage 5 configuration is the same as in the Stage 4 configuration. 
     The foregoing detailed description is for illustration only and is not to be deemed as limiting the inventions, which are defined in the appended claims.