Newsgroup: it.discussioni.auto
Titolo: Cartella stampa della Challenge Stradale (Inglese e lungo)

CHALLENGE STRADALE - THE CONCEPT
The new Ferrari Challenge Stradale lines up alongside the 360 Modena and 360
Spider with the precise aim of giving drivers the performance and feel of a
true racing car for road use.
This aim meant Ferrari technicians gave exclusive preference to Ferrari
Challenge and 360 GT racing-type solutions for all aspects of the car and
every single performance parameter, the combination of which give this car
its highly individual character.
The starting point was aerodynamics, where the aim was to obtain increased
vertical load, which gives more speed when cornering rather than a higher
top speed, and then all the vehicle-specific features (transmission, set-up
and braking, in particular the introduction of carbon-ceramic brakes as
standard). And finally, that determining factor for all racing cars -
achieving the lowest possible weight.
In fact the car's drastic weight reduction is one of the most significant
achievements of the Stradale project: the weight was lowered by
incorporating racing solutions for every single one of the car's components,
in addition to the benefit of using only aluminium to build it.
There's a choice of two Stradale versions: a more extreme one with racing
seats and sliding windows, and another, fitted with lighter, wrap-around,
leather seats and wind-down windows.
EXTERIOR AND AERODYNAMIC STUDIES
The Stradale builds on aerodynamic concepts employed on the 360 Modena by
taking advantage of the racing set-up (more rigid and lower) and adopting
specific solutions that have led to a gain of 50% in vertical load compared
with the 360 Modena.
The results are extremely significant: at 200 km/h the load increase is
about 40 kg for a gain corresponding to the effect of a wing with 15 cm
chord length and 1.8 m span.
Despite such a significant increase in vertical load, after all the
modifications and adjustments to set-up the car has a Cd equal to that of
the 360 Modena (Cd= 0.335).
Four types of intervention were adopted to improve aerodynamics on the
Stradale.
Front section: modification of the bumper, which now extends below the air
intakes to increase load at the front but without disrupting airflow toward
the rear.
Aerodynamic study of the car's underside and rear section: with the result
of an increase in height at the rear and introduction of longitudinal fins
to balance the load. The decision was also taken to modify the rear nolder
to achieve greater efficiency by adopting a shape more appropriate to the
function concerned.
Drag and modification of the sills: the new shape streamlines the rear
wheels more completely and contributes significantly to improving the car's
efficiency and balance. The combined result of these interventions is that
compared with the 360 Modena drag has remained unchanged, so leading to a
significant increase in efficiency.
CAR WEIGHT REDUCTION
Careful project development has led to a Stradale car weight that is fully
110 kg less than the 360 Modena, achieved by concentrating on three
complementary spheres: materials, construction technology and project
optimisation.
The basic material used to build the Stradale is aluminium, as was already
the case for the 360 Modena and Spider. Aluminium has been used for both
body components and, above all, the space frame, a combination of castings,
extrusions and plates. This initial approach towards drastically reducing
the Stradale's weight already made it extremely competitive (compared with
the 360 Modena) given that the basic material used, aluminium, has a
specific weight one third of that of steel.
Starting from this base new developments were introduced specifically for
the Stradale. Titanium, already used for the piston rods, was also adopted
for parts of the suspension, in particular for the wheel bolts (a 50% weight
reduction) and damper springs (a 27% weight reduction).
Carbon technology, derived directly from Formula 1 and used extensively on
Ferrari limited-run road cars, was employed for the first time on an
8-cylinder car. For the Stradale it has been used for both structural parts
(door panels, racing seat shells, filter-box covers) and for interior and
exterior trim features.
A particularly advanced construction technology was adopted for the car's
floorpan. This involves impregnating the resin with multi-axial carbon
fibres in a vacuum in order to obtain the necessary rigidity, but which
simultaneously leads to a 50% reduction in the weight of the floorpan
itself.
A key factor in the search for the best weight-performance ratio for the
Stradale was adopting a braking system comprising carbon-ceramic (CCM) discs
developed for Formula 1 combined with aluminium brake carriers as standard
equipment.
In terms of weight, the reduction achieved on the Stradale as a result of
CCMs is 16% compared with conventional brake discs, but given that the
weight eliminated affects unsuspended masses, its contribution to the car's
performance can be assumed to be even more significant.
Below is an overview of the drastic weight reduction achieved for the
Stradale (-110 kg), subdivided by the car's macro-assemblies:
Reduction % reduction in terms of total car weight
Engine and gearbox - 11 kg - 4%
Unsuspended mass - 5 kg - 3%
Body - 94 kg -12%
Reducing a car's weight also means a reduction in its inertia. The main
effect of this on the Stradale, together with the peak power increase
provided by the V8 engine, is a considerable increase in performance,
particularly as regards pick-up and acceleration.
The car accelerates from 0 to 100 km/h in 4.1 seconds and covers 400 metres
from a standing start in 12.1 seconds.
RACING INTERIOR
Essentiality - in the most specific meaning of the term - is the dominant
characteristic of the Stradale's interior, right from the elimination of
unnecessary features like carpeting and mats, to a racing-style
interpretation for every single feature.
The rev counter located right in the centre of the instruments becomes the
driver's main point of reference, emphasised by the yellow graphics and red
indicator that ensure optimum contrast and legibility. The entire panel is
enclosed within a carbon-fibre element that also houses secondary
instruments and other telltales.
The new steering wheel, with a squashed crown in the upper section fitted
with a sight just like on the racing version, has F1 gear-change paddles,
the right one having been lengthened to facilitate changing up when pulling
out of corners.
The car is fitted with carbon fibre-structure racing seats upholstered with
a high-grip textile. Door panels are made entirely of carbon fibre, as is
the tunnel, which has been designed to house all the car's main controls -
ignition button, reverse gear button, dynamic vehicle settings (race, launch
control, ASR excluder) within easy reach of the driver.
The car can be fitted with either 3-point attachment or 4-point racing
attachment seat belts and an aluminium roll-bar that's 40% lighter than a
conventional type, developed specifically for the Stradale.
ENGINE
The Stradale is equipped with the previous 360 Modena 90° V8 engine mounted
centrally behind the cabin in a longitudinal configuration as a single block
together with the gearbox and differential. Peak power output of the V8
engine has been raised to 425 bhp at 8,500 rpm to give an exceptional power
rating of 118,5 bhp/litre, which makes it the most powerful aspirated V8
ever built by Ferrari. The extremely high peak torque remains unchanged at
38 kgm at 4,750 rpm.
On the mechanical front, couplings for rotating parts in the Stradale's V8
have been carefully selected and this has led to a significant improvement
in performance.
Modifications to the engine can be grouped in the following areas:
Optimisation of the compression ratio by means of additional work on
components involved in it (Heads, Pistons)
Optimisation of the engine's fluid dynamics, by means of the following
interventions:
• use of an intake manifold with inserted stacks and burnished ducts, in
addition to burnishing the intake ducts and head exhaust;
• optimisation of the section and head of the intake manifold coupling;
• use of a specific intake timing;
• use of a new low-load loss, airflow meter;
• new low counter-pressure exhaust silencer.
Optimisation of mechanical performance was achieved by means of the
following interventions:
• selection of low-friction cylinder blocks;
• new positioning of valve-springs.
F1 GEARBOX
The entire development of the Stradale was based around F1-type
electro-hydraulic transmission that controls the clutch and gearbox by means
of blades integral with the steering column - a trademark of Ferrari cars
and a solution developed specifically for racing.
The increase in precision guaranteed by the new control strategy applied
specifically to this car, and also by a faster processing speed, has reduced
gear-change time throughout the entire range of use, with a minimum of 150
milliseconds when using the super-performance option.
The available gear-change configurations are consistent with the car's
top-level sporting profile and so only include manual gear-change operated
by the driver using F1-type paddles (there is no automatic gearbox option).
The reverse gear is engaged by means of a button on the tunnel.
There are two gear-change configurations (Sport and Race): each of these
configurations corresponds to an integrated car-control logic as regards
damper set-up and traction control (ASR).
In “RACE” mode and with the ASR disengaged there's also a “launch control”
strategy as used in Formula 1, a feature specially designed to give drivers
a high-performance start in good grip conditions.
CHASSIS COMPONENTS (suspension, set-up, wheels)
The Stradale has been derived from the 360 Modena and maintains the same
basic approach and architecture. However significant changes have been made
to the suspension system and set-up. The titanium front and rear springs are
more rigid than on the 360 Modena (around +20%), whereas the rear bar has a
larger diameter. These interventions have increased resistance to roll and
dip and in general terms have made reaction to direction changes more rapid,
giving the driver a more direct feel of the car.
Damper settings have been reviewed and defined specifically for this model.
The car's centre of gravity has been lowered by 15 mm.
The tyres are Pirelli P Zero Corsa type - this new Pirelli super-low tyre
adopted specifically for the Stradale measures 225/35 at the front and
285/35 at the rear and is fitted on 19" Challenge-style wheels secured by
titanium bolts.
CARBON-CERAMIC BRAKES
The braking system on the Stradale comprises carbon-ceramic (CCM, Carbon
Composite Material) discs: the result of highly advanced studies conducted
by Ferrari in conjunction with Brembo, the supplier of this system.
Dimensions of the brake discs are as follows:
front: 380 mm diameter x 34 mm thickness, and a differentiated-diameter,
6-piston calliper;
rear: 350 mm diameter x 34 m thickness; and a differentiated-diameter,
4-piston calliper
The carbon-ceramic system installed on the Stradale, together with the
aluminium brake carriers, makes for astounding performance and braking
distance levels.
In terms of weight, the reduction achieved for the Stradale is 16% when
compared with conventional brake discs.
Overall deceleration rates for the Challenge Stradale are 15% better than
for the 360 Modena.

 than for the 360 Modena.
Notevole.
gi