2015 WRX Project Northstar – Killer B Catless J-Pipe

Continuing on with the power stuff we next added a catless Killer B J-Pipe and Intermediate Pipe to the car. As with most turbo cars the exhaust is usually one of the biggest restrictions to making more horespower and torque. Like most Killer B products the J-Pipe fit pretty much perfect and the quality is very good. The most difficult part was removing the factory J-Pipe to Turbo nuts/Studs which we’ve seen before pose big issues. We had to really heat up the studs with our torch in order to get things apart and we’d recommend either having new nuts/studs or replacing the studs with bolts when doing this job. Once that was out of the way the new pipes went on nicely and with the supplied graphite gaskets were able to seal up with the factory cat-back system. One thing I noted while doing the install is the factory cat-back does not have the typical resonator in the mid-pipe like previous generations. There’s a resonator in the intermediate pipe which we replaced. Upon start-up this became very apparently as the exhaust was very raspy and hollow sounding. The turbo/induction noises were cool but ultimately it was not what I wanted and we already had a cat-back on the shelf for the car but wanted to add that after. While doing this we also removed the second restrictor pill as noted by COBB’s map notes to try and help boost control. On to the important parts, we strapped the car onto the dyno and let Sasha at OnPoint dyno do his thing. As expected the car made more power, we saw an increase in torque of about 15ft/lbs and horsepower increased by around 25WHP compared to with the TGV and Intake alone. This brings our overall increase from stock up to 33% Horsepower and 26% torque.

The spikes in power you see are caused by the boost control system and rather then spending time messing around with it we had Sasha get it relatively safe since we had a Grimmspeed EBCS, different J-Pipe and Cat-Back to install before final tuning was to be done.

Event: Dyno
Location: Touge Tuning, Mississauga Ontario
Ambient Temp: 15C – May 2015
Elevation: 249 ft.
Weather: Warm
Car: 2015 Subaru WRX
Tuner: Sasha from OnPoint Dyno
Dyno Info: Dynapack
Transmission: Stock 6 speed
Gear: 4th
Stage 2 + TGV + Intake Peak HP at RPM: 280 @ 5900RPM – SAE J1349 (2004) Corrected
Stage 2 + TGV + Intake Peak Torque at RPM: 315 @ 2900RPM – SAE J1349 (2004) Corrected
Stock Peak HP at RPM: 212 @ 4900RPM – SAE J1349 (2004) Corrected
Stock Peak Torque at RPM: 250 @ 2500RPM – SAE J1349 (2004) Corrected
Baseline HP/TQ for Stock 2010 STi on same dyno: 228WHP/240WTQ
Target Boost: 20PSI Tapering
Fuel: 94 Octane Petro Canada

Mod List
-COBB AccessPORT – Custom Tune
-Turn In Concepts TGV Deletes
-AEM Intake
-Killer B Cat-Less J-Pipe and Intermediate Pipe

Thanks to these companies that are helping with this Project
COBB Tuning – COBB AccessPORT and COBB Cat-Back
Mad Graphics – Full Vehicle Vinyl Wrap and Side Graphics
Grimmspeed – License Plate Relocation Kit
Turn In Concepts – Shifter Bearing and TGV Deletes
Killer B Motorsports – J-Pipe
OnPoint Dyno – Dyno Tuning and Testing
Uni-Body Collision – Paint Work (Emblems, Lip, Trunk Spoiler)