A stock STI is a great package form the start. Starting the modification process with a stock car isn’t as easy as most will think. Any project needs an end goal in order to be successful. The main goal behind the 2006 I-Club Project STI is to have a capable street performer and to wreak havoc at weekend driving events (including time attack). With that in mind the best thing to do is to start simple.
Our first stop was with Buschur Racing. BR carries a strong reputation in the Evo & DSM world for building some of the fastest cars in the industry. Being new to the Subaru market, we wanted to give their products a try to see what kind of results we could get. Keeping things as simple as possible, we decided to start with Buschur’s 3-inch turbo back exhaust (with high flow cat), 2 ¼ inch up-pipe, and cold air intake. To keep things in perspective we wanted to run the car with the current setup on the dyno to start off with a base line. Then we installed each product (one at a time) and dyno’d the car to see what kind of power we could get out of each part. Stock Dyno Graph:
Buschur Turbo Back Exhaust & Up-Pipe The build quality is excellent (welds are perfect and bends are top notch) and most don’t compare to the overall build standards of the BR exhaust. One thing this exhaust is not is a polished dressed up visual perfection that you normally see under a car entered at a hot import night’s event. Making power is serious business and this exhaust doesn’t steer away from that concept. On paper the turbo back exhaust boasts a weight savings of about 39 pounds over the stock system, which is a great benefit when you have a double duty car that spends time on track. Installing the exhaust was fairly easy and didn’t take much time at all. We did have to trim back the rear black plastic diffuser to make sure we got enough clearance, which is the only issue we ran into. Other then that it was a perfect fit. Next we decided to add the up-pipe. In order to fit the entire test in one day we weren’t able to dyno the car with just exhaust separately from the up-pipe, so we had to install the up-pipe at the same time as the exhaust. Installation for the up-pipe took the most amount of time mainly because of its location. Once we got the exhaust and up-pipe on the car it was time to start it up and get it on the dyno.
Once the car was started, the exhaust tone belted out the meanest sound across the shop in a very good way. The BR exhaust accentuated the boxer motor sound.
24 whp & 34 lb tq is a substantial gain for just a up-pipe and turbo back exhaust. So far so good and it was now time to get the intake installed.
Buschur Cold Air Intake First impression of the intake build quality was very good. Since this was an item that could be seen it did help that the part looked more polished. Installation was very easy and took about 30-45 minutes to install. After the install we strapped the project STI back on the dyno to get some more numbers:
With the intake we were able to extract another 5whp but we did lose 5 lb tq at the wheels.
Conclusion At the end of the day the results speak for themselves. A whopping 29whp gain over stock and 29 lb tq at the wheels without tuning. BR really has come up with the best combo to get the STI to produce substantial gains without having to dig too deep into your wallet. Getting the car on the road also proved even more impressive impressions. Throttle response was much more crisp and felt like the car was freer revving. The car picked up more lower end torque and had more juice up in the rpm range. With a custom tune we can expect higher numbers but for now this setup was much better then with what we started with.
Whenever the modding process is begun, always make sure to think through your plan before you get started. Simple may not sound exciting but with the power we gained, you can’t argue with the end result.