Hey everyone, Emmy here again and welcome to another episode of Cob You. Today's topic is a cool one indeed. Now our primary objective with tuning is to make our engine run as efficient as possible. In our previous episode we discussed that the more air you can cram in and evacuate in a timely manner, the more power you can make. Now we have our turbo to thank for compressing the air, but with the added pressure comes heat. Hot air is less dense, which is not what we want when we're trying to make more power. An inner cooler is the best way to reduce that increased intake air temperature, which is a natural byproduct of turbocharging, which is why almost all the cars we support here feature an inner cooler of some type. Most stock inner coolers are capable of sustaining stock power levels for your daily driving, but not much more. You may find that as you add more power or take your car to the track, that the factory inner cooler system isn't up to the task. Case in point, let's take a look at a stock inner cooler from a Ford Mustang EcoBoost and an upgraded Cob inner cooler. One of the first things that you'll notice is the difference in size. Our inner cooler fits into the same location as the stock one, but it's much deeper, allowing the air that much more room to get cool. At both sides of our inner cooler are our end tanks. The stock inner cooler has plastic tanks that could fail under heavy load. The common issue is the tanks separate from the core. Best case scenario, the car makes less boost. Worst case scenario, you're on the side of the road waiting for triple A. The upgraded inner cooler on the other hand has beefy cast aluminum end tanks that are welded to the core and can take whatever you can throw at it. Now that you have a better understanding of some of the differences between stock and upgraded inner coolers, let's go over some of the basics, like what makes up an inner cooler system, or how you benefit from it, or even why you should consider upgrading. There are a few styles and choices of inner coolers out there, but for the sake of today's demonstration, we'll be using air-to-air inner coolers made up of bar and plate construction. If you want to learn more about other types of inner coolers, you can visit our extra credit below. Also, we're using parts from a Subaru WRX STI, so your setup might look different. Your basic inner cooler system is going to be comprised of a core with end tanks and the necessary couplers, clamps, and piping. We'll also be discussing the bypass valve, but we'll get to that in a little bit. The aluminum core is made up of layered internal and external air passages that lay perpendicular to each other. The internal ones where our charged air will travel run from one side to the other. The external ones, which have outside air passing through them, run front to back. Then we have aluminum piping that has a larger diameter than the stockpipes to reduce airflow restriction, and various multi-layer silicone couplers with high-strength clamps designed to hold increased pressure. Now that we know what our components are, how do they all work? As our hot, charged air leaves the compressor of our turbo, it travels through this series of tubes and couplers, referred to as the hot pipes, and enters the inner cooler core. As the air moves through the internal passages of the core, its temperature decreases because the heat transfers from the air to the metal core. Cooler air from the outside passes through the external fins on the core in an effort to reduce the temperature of the core itself. Finally, the cooled air makes its way out of the inner cooler and up through this series of tubes and couplers, referred to as the cold fights, as it makes its way to the throttle body. While there are quite a few different setups, the most common you'll see are top-mount inner coolers or top mounts like this car and front mount inner coolers or front mounts like this car. Like the name suggests, top mounts reside on top of the engine, and front mounts are placed low and in front of the car, typically within the bumper opening. Now top mounts and front mounts both have their own sets of pros and cons. One of the pros to top mounts is reduced plumbing, which increases throttle response. This is because the air has less distance to travel. It comes out of the turbo here, into the top mount, and right into the throttle body. One of the drawbacks to this is it sits right on top of the engine, making it prone to heat soak. This is a common problem in stopping ghost city driving. In stationary or moving slow, heat rises from the engine, soaking the inner cooler and heat. As you get moving at a high rate of speed, air comes through the hood scoop, down to the inner cooler, cooling it. Now due to the under the hood packaging constraints, top mounts are usually smaller, which limits the amount of air it can cool, and the amount of charged air that fits inside, putting a cap on the potential power you can make. Front mount inner coolers sit low and in the front, so they aren't affected by underhood attempts like top mounts are. The catch is that the charged air has a much further distance to travel, coming out of the turbo, going all the way around into the throttle body. This causes a delayed response in some conditions. The primary thing to consider is that what's right for someone else's setup might not necessarily be right for yours. Depending on your car's needs and goals, your stock inner cooler might be sufficient or completely inadequate. At the end of the day, it's putting your car's needs over aesthetics or anything else. Now earlier we mentioned the bypass valve. The bypass valve, sometimes referred to as the diverter valve, is located somewhere between the outlet of the compressor side of the turbo and the throttle body. In this case, it sits right here, just before the throttle body. Now when you let off the accelerator, the throttle blade slams shut, and all this excess boost pressure needs somewhere to go. If you allow it to bounce off the closed throttle, it'll attempt to make its way back through the system, slamming into the compressor wheel, attempting to spin it backwards. This causes a symptom called compressor surge. It makes an awesome chirping sound on race cars. Which is really cool, but terrible for your turbo. Most pro racing teams have the budget to replace their turbo and engine after every race, which most of us don't. Now to avoid this, the bypass valve directs air through a hose into the turbo inlet, keeping the system flowing smoothly. It does this by routing air much like a wastegate. Both are air actuated, both have a spring to help them stay shut when it rests, and they're both valves that allow air to flow when they open. There are a few differences though. The wastegate has exhaust flowing through it while the bypass valve has charged intake air. Also the wastegate is opened by pressure, and the bypass valve is opened by vacuum, so it's being pulled open rather than being pushed open. In order to actuate a bypass valve, the body on top of the piston connects via this hose to the intake manifold, which experiences both positive pressure and vacuum. In our previous episode, we discussed barometric pressure, and how boost was a positive pressure on top of barometric. Vacuum is often referred to as a negative pressure because it's lower than barometric. The vacuum needed to open the bypass valve is created here in the intake manifold when you close the throttle and the engine keeps trying to suck air in. Since the bypass valve is connected to the manifold, the piston gets pulled up, exposing the air passage at the bottom and diverting air back to the inlet. When you're enduced, the butterfly valve is open, and vacuum changes to positive pressure as air is forced through the manifold into the engine. The boost pressure from the manifold plus the bypass valve's internal spring pressure keep the bypass valve shut and air continues into the engine. Now it's important to note that a blow-off valve is not the same thing as a bypass or diverter valve, while similar in construction, a blow-off valve vents air directly into the atmosphere instead of recirculating it. Many people will install blow-off valve solely for the sound that it makes. Yeah, it sounds cool, Bra, but it does absolutely nothing to help your car run any faster. The ECU calculates the amount of fuel needed based on the amount of air it's expecting from the map sensor reading. Now when air leaves the system through a blow-off valve, it creates a rich fuel mixture, rich meaning there's more fuel to air because some of it's gone missing. On this case, a blow-off valve is less of a performance mod and more of a make your car run worse mod. Lastly, when doing this type of part install, you will generally use these kinds of tools. Ratchets and sockets, screwdrivers. And now it's time for the pro tip of the day. Inner cooler kits have many points of connection. Each connection point is a potential boost leak. If you aren't hitting your target boost for the calibration you're running on your ECU, here's where you'll begin your search. Starting with the couplers and clamps, make sure that you have a solid connection all the way around the piping. It might look like your coupler is making good contact, but think about what's behind, what you can't see. Once you know your couplers are safely seated around your piping, tightly secure your clamps. Another part you'll want to check is the bypass valve gasket. If you're unable to perform a smoke test to confirm any leaks, the gasket is an inexpensive part to replace, so it's cheap insurance. If you want to learn more about smoke tests, you can visit our extra credit link below. As usual, to get the most out of the parts that we change, we need to make sure that we flash the proper calibration to our ECU. If you're unsure about what calibration you should be running, you can check the map notes included in our off-the-shelf maps or contact your local Cobb Pro tuner. Truth be told, it's not the end of the world if you don't retune for an upgraded inner cooler. However, it doesn't make sense to spend all that money on an upgrade and not get the most potential out of it. That's going to do it for this episode. In our next video, we'll explore the fuel system and the various components needed to deliver the right amount of fuel when you need it. Thanks for joining us and be sure to subscribe to our YouTube channel so you can check out future episodes. I'm Emmy, your host for Cobb You. Remember, check out CobbTuning.com for all your parts and tuning needs. Do you like the storage solutions featured in our studio? Then visit sonictoolsusa.com to get more detailed product information.