how to extreme

Exhaust System Improvements

Automotive August 12, 2015 Sonia








Corsa’s Subaru exhaust system improves sound and adds power.

By Larry Walton

Mention Subaru’s STI to auto enthusiasts and the reaction is often the same: “That’s a fun car to drive.” Iconic rally images of this car tearing up stages in international competitions fuel the imagination of Subie enthusiasts, but owning one is not just a dream for many, because a reasonable price makes the WRX STI one of the best values in a performance car.

The turbo-charged STI features solid low-end torque and plenty of top-end kick with the turbo spooled up. It also has upgraded brakes and good quality suspension right off the showroom floor. What’s missing is that classic “Subaru rumble,” because the stock exhaust is a bit too tame. This calls for an aftermarket exhaust to improve performance and to get that classic Subie exhaust note. Enter Corsa’s excellent cat-back upgrade for the STI.

Performance Exhaust System

Every Corsa Performance Exhaust System we’ve tested has provided a solid blend of performance, great exhaust note under acceleration, and droneless cruising sound. We expect this Subie version to live up to the Corsa standard for sound engineering and quality build.

The numbers this stock STI produced on a dynometer were definitely in line with other stock STIs from this generation tested on the same dyno.

I noticed from the comments I heard at the garage that the exhaust arrived in better-than-usual packing materials. Some exhaust systems are simply thrown into a box and arrive pretty beat up. The Corsa system was well protected, and components were kept separate in foam.

Typical of most cat-back installations, after removing the connection between the catalytic converter and the resonator, the rest of the stock system came off by simply releasing the exhaust hangers. We could then compare the two exhaust systems.

Yes, in this case, bigger is better. Once the stock exhaust was on the shop floor with the new Corsa system, it was easy to see that the difference in pipe diameter was going to mean better exhaust flow.

The Corsa system went on without a problem. Clearances, clamps and hanger positions worked flawlessly, and the tips look great with subtle Corsa logos visible in the right light.


[01] 3LW_1660

Before doing any wrenching, we strapped the STI on the AWD Dynojet at Garage 808 for some baseline numbers. This is the best way to find out if a performance upgrade produces results. Under these controlled conditions, it’s pretty easy to see the numbers, especially for clients viewing the read-outs of the flat screen in 808’s comfy dyno observation room.

[02] DSC_0160

Removal of the old system was straightforward. After supporting the pipe, my son Tim removed the nuts and bolts at the connection between the catalytic converter and the resonator.

[03] DSC_0165

He used this specialty tool to disconnect the exhaust hangers from the exhaust hanger posts on the stock exhaust, but you can get it done with a screwdriver and some trial-and-error effort.