The 2-liter EJ20 turbo engine used in the WRX is an amazing power plant that creates around 230 horses straight off the dealer’s lot. With a few simple modifications, the engine can produce over 400 horsepower. In fact, some most of the mods are so easy, that you can do them yourself.
If you are a performance junkie, A few WRX tuning tips can help you quickly increase the performance of your Subaru.
There are literally hundreds of intake and exhaust mods made by aftermarket manufacturers that add more horsepower to your WRX. A good direct intake system will increase airflow in your Subaru’s engine and improve compression and power. A quick install of an open-element air filter will quickly add about five more horsepower to your EJ20 engine.
The stock exhaust system on a Subaru WRX uses tubing that is very small in diameter and restricts sufficient airflow needed to increase horsepower. Although the stock exhaust system does a good job of minimizing noise, it does somewhat limit the performance of the vehicle. You can choose to replace only the rear section of the exhaust tubing with systems made by Blitz Turbo XS or others and again about 10 to 15 horsepower. Other systems called ‘cat-back’ exhaust systems add an additional pipe which extends all the way to the rear catalytic converter of a vehicle and can provide even additional power gains.
The key to getting more power from your WRX is in increasing the boost pressure that the turbocharger creates. More pressure from the turbocharger means that more air and fuel can be forced into the cylinder on each compression stroke. More fuel in the cylinders of your WRX means more power. However, too much of a boost in pressure can also damage your engine. Therefore, you should always install a boost gauge before attempting to increase boost pressure.
The easiest way to boost pressure in your Subaru’s turbo engine is to install a boost controller. This device allows you to manually specify the boost pressure you desire. The advantages of this type of control are its ease of use and its low price. However, if you’re not careful with the settings, you can severely damage your car’s engine.
The other, more sensible approach to upgrading the boost pressure in your vehicle is to upgrade your WRX’s electronic control unit chip. This also can increase boost levels as well as allow you to change timing maps, revolution limits and even remove speed governors. While upgrading the ECU has definite advantages, it is quite costly and will often cost $1000 or more.
Although the Subaru’s WRX’s engine is a shining example of automotive craftsmanship, the turbocharger leaves a little to be desired. The stock turbocharger has a rather limited capacity for airflow at high RPMs. To create more horsepower with a turbocharged engine, you need high boost at high RPMs.
There are many aftermarket turbo chargers that can be bolted directly onto the Subaru intake and exhaust system. If you do change the turbo, however, you’ll also need a new set of fuel injectors as the factory installed injectors won’t be able to handle the larger capacity turbo.