The key to getting horsepower from the turbocharged motor is to increase boost pressure produced by the turbocharger. More pressure means more air and fuel can be stuffed into the cylinder on each stroke, and more fuel in the cylinder means more power produced.
But too much boost can be bad. At some point the fuel system will not be able to deliver enough fuel to match the air that is being forced into the cylinder. The fuel-air mixture will become too lean, and will burn very hot. Those extremely hot temperatures can severely damage pistons and valves, and can destroy your engine.
This is not much of a problem early on in the modification process, but to be safe we urge you to install a boost gauge (if you don't already have one) as the first modification to your WRX. The boost gauge serves several purposes. It can help you understand when and how much boost the car makes. It can clue you in to when things are running right, in the case of over-boosting, or not reaching normal boost. Plus it just looks great. The Prosport Halo gauge, above, is one of our most popular boost gauges. It's one of a number of gauges that we carry that has a peak-hold function, so you can have the gauge remember the maximum boost it has seen. It also boasts a warning light and beep if the boost level goes over your preset maximum.
A boost gauge can be installed in a number of locations, but the A-pillar (the one that connects the dash to the roof), the gauge surround, or the center dash are great locations. Or you can install a gauge in a stand-alone gauge cup. We even have a windshield pod for the 2008-2014 cars.
Next: High-flow intake systems.