Going from Stock to Stage 2+ on a 2011 Subaru WRX – Dyno Numbers

At Touge Tuning we strive to provide as much useful information as we can to help you understand what you’re getting when you modify your Subaru.  In this instance we took the very popular 2011 Subaru WRX and went from stock to Stage 2+ and dyno’d it between the major steps to show the gains.  This is a typical WRX which was purchased second hand from a Subaru dealer and there’s nothing really noteworthy about it’s history.  The car had around 70,000KM on it and didn’t appear to have been modded previously.  From purchase the car has been ran on Petro 94 Octane.

Enough of that though, on to the parts you came to see and read about.  So the first step was to get some baseline HP and Torque figures so we know what it came in with.  As always we called upon the services of OnPoint Dyno to provide dyno and tuning services using his AWD Dynapack System.  We loaded the car onto the dyno and proceeded to do 3 pulls taking the strongest pull as the reference.  As the car came in it put out 225WHP and 256lb-ft to the wheels.  Not bad for a WRX given when we tested the 2010 STi it only made 228WHP stock.  We then reflashed the car using the COBB AccessPORT and the COBB OTS Stage 1 map.  We then did the same process for the dyno pulls aiming to be as consistent as possible.  The car made 224WHP and 283lb-ft which is actually a 1HP (-.5%) drop compared to stock.  This would not really be noticeable when driving the car.  What really makes the biggest difference going stage 1 is the low end torque increase which is where you spend a lot of your time driving these cars.  From a basic reflash the car gained 27lb-ft(10.5%) of torque and the gains are pretty substantial from 3000RPM all the way to 5000 RPM where the stock exhaust really becomes a choke point for the exhaust flow.

Event: Dyno
Location: Touge Tuning, Mississauga Ontario
Ambient Temp:
Elevation: 249 ft.
Weather: -8C
Car: 2011 Subaru WRX
Tuner: Sasha from OnPoint Dyno
Dyno Info: Dynapack
Transmission: 5-speed
Gear: 4th
Stock Peak HP at RPM: 225 @ 5800RPM – SAE J1349 (2004) Corrected –
Stock Peak Torque at RPM: 256 @ 4100RPM – SAE J1349 (2004) Corrected
Stage 1 Peak HP at RPM: 224 @ 5700RPM – SAE J1349 (2004) Corrected –
Stage 1 Peak Torque at RPM: 283 @ 3500RPM – SAE J1349 (2004) Corrected
Baseline HP/TQ for Stock 2010 STi on same dyno: 228WHP/240WTQ
Target Boost: N/A
Fuel: Petro 94

Next up while on the dyno we threw on the AEM Cold Air Intake and reflashed the car to the Stage 1+ map.  The results are interesting as the car made more horsepower and torque then stock but less then the OTS Stage 1 Map.  The reason for this is that the map would just not make target boost and we didn’t want to do any custom tuning at this point.  If it had achieved target boost we would likely see a gain of another 5-10 HP and torque.   So in this instance we would see a slight gain over stock with the intake despite what many will tell you.

Stock Peak HP at RPM: 225 @ 5800RPM – SAE J1349 (2004) Corrected –
Stock Peak Torque at RPM: 256 @ 4100RPM – SAE J1349 (2004) Corrected
Stage 1+ Peak HP at RPM: 229 @ 5900RPM – SAE J1349 (2004) Corrected –
Stage 1+ Peak Torque at RPM: 278 @ 3550RPM – SAE J1349 (2004) Corrected
Target Boost: 17.5PSI +/-1PSI
Fuel: Petro 94

Next up was to get rid of the biggest restriction on pretty much any turbo Subaru and that’s the stock downpipe and cat-back exhaust.  For this we turned to Invidia and installed one of their High Flow Catted Downpipe’s and the Invidia Q300 Cat-Back Exhaust System.  This is one of the most common set-ups and rightfully so as it performs great and fits well while being one of the few true 3″ systems on the market.  With these 2 parts installed we flashed the car COBB OTS Stage 2+ and immediately the power increase was substantial.  We saw a peak horsepower reading of 271whp which is 46HP(20.4%) more then stock.  Torque jumped up to a staggering 305lb-ft which is 49lb-ft(19.1%) more then the stock baseline.  The horsepower jump is  a little inflated as the car was exhibiting the infamous “boost creep” that is common on the VF52 equipped WRX models when you install a turbo-back and intake system.  Because of this the boost in the upper rpms was not dropping as expected and inflated the HP numbers slightly.  Based on experience we would estimate without the boost creep the HP would have peaked around 262-265WHP.    Even still this would equate to a 37HP gain over stock with 4 very simple modifications that don’t put the engine or drivetrain at risk.

Stock Peak HP at RPM: 225 @ 5800RPM – SAE J1349 (2004) Corrected –
Stock Peak Torque at RPM: 256 @ 4100RPM – SAE J1349 (2004) Corrected
Stage 2+ Peak HP at RPM: 271 @ 5800RPM – SAE J1349 (2004) Corrected –
Stage 2+ Peak Torque at RPM: 305 @ 3600RPM – SAE J1349 (2004) Corrected
Target Boost: 17.5PSI +/-1PSI
Fuel: Petro 94

To finish things off we had Sasha from OnPoint do a custom tune with the mods not only to make the engine operate it’s best but also to show the power gains that can be had between an Off-The-Shelf tune and a custom tune.  So Sasha went to work and did some of his tuning wizardry and the results really speak for themselves.  Not only do we know the tune is less aggressive and safer but it also makes more power everywhere.  Final numbers were 287WHP and 322lb-ft with the custom tune.  Compared to the OTS map that is an increase of 16HP (5.9%) and 17lb-ft (5.6%).  We did still experience boost creep since this cannot be tuned out completely as it’s a mechanical issue.  However it was less severe and you can see the power is more linear compared to the creep on the OTS map.

Stage 2+ OTS Peak HP at RPM: 271 @ 5800RPM – SAE J1349 (2004) Corrected –
Stage 2+ OTS Peak Torque at RPM: 305 @ 3600RPM – SAE J1349 (2004) Corrected
Stage 2+ Pro-Tune Peak HP at RPM: 287 @ 5800RPM – SAE J1349 (2004) Corrected –
Stage 2+ Pro-Tune Peak Torque at RPM: 322 @ 3700RPM – SAE J1349 (2004) Corrected
Target Boost: 18PSI Tapering
Fuel: Petro 94

Now for the conclusion we can look at the change from stock to how the car was finished with the new mods and new tune. The horsepower increased from 225WHP to 287WHP which works out to 62HP or 27.6%.  The Torque jumped from 256lb-ft to 322lb-ft which makes for an equally substantial gain of 66lb-ft or 25.8%.  It really is amazing being able to add an additional 25%+ in power and torque with some simple bolt-on parts and tuning.  We hope this information will be useful in you modding your car and understanding what to expect.

Stock Peak HP at RPM: 225 @ 5800RPM – SAE J1349 (2004) Corrected –
Stock Peak Torque at RPM: 256 @ 4100RPM – SAE J1349 (2004) Corrected
Stage 2+ Pro-Tune Peak HP at RPM: 287 @ 5800RPM – SAE J1349 (2004) Corrected –
Stage 2+ Pro-Tune Peak Torque at RPM: 322 @ 3700RPM – SAE J1349 (2004) Corrected
Target Boost: 18PSI Tapering
Fuel: Petro 94