Whether you are a true die-hard car enthusiast or just getting into the world of cars, this was likely one of the first modifications you did to your car. It's one of the easiest parts to access and install on almost every make and model, it dresses up your engine bay nicely, and makes for some real fun turbo and intake sounds under wide open throttle. You guessed it, we are talking about the cold air intake. Besides the obvious perks, we are going to be exploring the real benefits to the cold air intake. And for the sake of explanation, we are going to specifically test it on Subaru's newest flat-four turbocharged engine. The FA20 which is fitted in all the new 2015+ WRX's.
When developing an intake and deleting a factory airbox you have two major goals in mind. Decreasing restriction and relocating the filter to an area that allows it to draw in cooler air. For obvious reason's these both are huge benefits to the car. Colder, denser air means for more power. Less restriction means more of the newly colder air making it into the combustion chamber, and the engine is working much less to draw that air in. With these new factors at work, you can pick up some nice power gains for cheap, and without spending hours under the hood.
With our new found knowledge of the cold air intake system, let's take a look specifically at the factory set up for our 15+ WRX. With one look at the factory intake system off of the car, you can see some major issues. Knowing that our goal is to reduce restriction and airflow disruption this factory system falls short. Subaru uses a soft plastic intake tube with multiple flex sections throughout the piping. As air passes over the ridged sides of the intake pipe its flow is heavily disrupted. This creates a bouncing effect and leaves the airflow tumbling over itself on its way to the turbo. That congestion means the motor has to work harder to bring in the air. Below is a picture that outlines some of the flex sections in question.
As you can see the intake pipe is full of bends, flex sections, it has choke points, it varies in size from 2.5" down to 2.0". All of which suffocates the FA20, and kills power. We at ETS knew a system this constricting had a ton of room for improvement. This thought process leads us to produce a 3.0" intake kit for the WRX. Our system has virtually eliminated all restriction. With a 3.0" section of piping all the way through, we managed to avoid these issues found in an OEM system. The air flows openly through the pipe, without having to compress down through a slimmer section. We also wanted to ensure we kept bends to an absolute minimum. As you can see in the pictures below, you can almost see straight through our systems like a telescope. And trust me your car appreciates the path of minimal resistance.
In true Extreme Turbo Systems fashion, we took the ease of flow a step further. Every single intake system that leaves our shop is hand ported to ensure that any air disrupting bits of slag, any burs, or imperfections are completely eliminated from the system. The pictures below are of the inside of our 15+ WRX intakes on the shelf right now here at Extreme Turbo.
Eliminating restriction has been resolved with the piping, moving upstream and looking at the factory airbox brings up new issues. First off, the flat paper filter that these cars come with will stifle your car's ability to breath. This is why we use a 5.0" cone style filter in its place. This allows for the absolute maximum surface area for the filter. This makes for a ton of less resistance on the turbo and engine as you open of the throttle.
Now we do need to take a moment to tip our hat to Subaru, the factory ram air ducting that picks up cool air from the front of the car and forces it up into the fender, and into the airbox is quite well done. This was a design we did not want to alter at all, but instead, build on. Our intake kit comes with an optional airbox that comes coated in a wrinkle black finish to keep your new intake stealthy under the hood. This airbox plays a few crucial rolls. The first and most obvious is that it protects the air filter from excessive dirt, water, or debris. Because let's face it, hydro-locking a motor after a sneaky puddle on the freeway explodes in front of you is nothing short of devastating. The air-box also plays a very important part in keeping the warm air from the engine bay away from the filter, while allowing the cold air from Subarus ram air ducting to pour over the filter. It's final roll and probably the most crucial is to protect the air filter from outside air. The air coming through the front of the car when driving can cause additional air to be taken into the system. This can cause the MAF to get false readings and the car can run rough. The MAF set up is so sensitive on the WRX that any extra unintentionally digested air will send the cars fuel trims out of wack and leave the car in a potentially lean condition.
Now, before we have anarchy on our hands lets clarify why you DO NOT need a tune with the ETS WRX Intake kit, and why you will see gains from simply installing the part. We use a MAF housing that is extremely similar to the factory housing dimensionally. This housing allows for an air meter that has an equivalent amount of air from as the factory piping as it air passes over the MAF. Meaning you are not pumping a huge amount of air over the sensor, as you would with a 3.0" MAF housing. This allows fuel trims to stay almost the same and there is no need for additional fuel. (see data below) Our housing also comes with a 5.0" velocity stack sitting inside the filter. This allows for smooth airflow and transition into the housing. Any turbulence or tumbling of air across this sensor can make for some false readings and create a whole bundle of issues.
With all this, we do want to address one thing. A cold air intake is usually only good for about 10-20hp gain. It is a simple mod that frees up a lot of strain on the turbo more than anything. A bone stock car really doesn't require more air, but when you start cranking up the boost the intake system really starts to shine. This is an absolute must-have if you really intend on trying to make power. Whether you are building an FA20 WRX or an LS7 Corvette adequate air flow with minimal disruption is an absolute must. Let our WRX Intake kit help your car take a deep breath of boost that it has been craving.
Craig Atkins III
Go Fast Parts Seller