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COBB Tuning Surgeline - 2015 STi Accessport Install/Tune - Stage1 and Stage2 Results


Event: Dyno Pull
Location: COBB Tuning Surgeline, 16580 SW 72nd Ave, Portland, OR 97224
Ambient Temp: Moderate (~70F)
Elevation: ~200 ft. above sea level
Weather: Overcast and cool
Track and Conditions: Indoors
Tires: Stock 2015 STI Launch Edition

Car: 2015 STI Launch Edition
Tuner: Lance Lucas
Dyno Info: Mustang MD-AWD-500
Transmission: 2015 STI 6MT
Gear: 3rd
Peak HP at RPM: 281 whp 
Peak Torque at RPM: 326 wtq 
Baseline hp/tq for a stock on same dyno: 254 wtq, 250 whp (Stock 2011 STI)
Target Boost: Stock then 17psi on AP Stage1
Target AFR: Stock then ~11.2 on AP Stage2
Fuel: Oregon 92 octane
Modifications: COBB Accessport, COBB Downpipe, Perrin Catback.

Hey guys,

We recently got a chance to take some baselines and Accessport Stage1 dyno pulls on a fresh 2015 STI Launch Edition here in Portland. Nothing overly fancy, just some basic baselines then Accessport install with follow-up dyno runs. All pulls, stock and tuned, were done in S#.

- The first two runs were completed exactly as the car arrived. This was at mile 631 and it appeared DAM (ignition multiplier) had settled on its full value of 1.0.
- The second two runs were completed following a fresh ECU reset to illustrate the change in power when the ECU has not yet done any DAM adjustments, or for when DAM is low when detonation has been previously encountered.
- The last two runs were completed after installing a V3 Accessport and the "Stage1 91 v340" OTS map.

Misc thoughts:

- Yet again we're seeing absolutely great power stock compared to the previous years. These new 2015 STi's are awesome!
- The Stage1 91 map worked really well on this car w/o any changes. Power across the board is up, except for 100-200 RPM at the very end of the run. This is due to the very aggressive timing values used by the stock tune when ignition multiplier is full. The OTS map actually runs much lower (safer) timing in this area.

Stage2 Update! - 6/19/2015

Vehicle has also been tested with a full TBE exhaust. We added a COBB Tuning Downpipe and Perrin Catback exhaust to the car and hit the dyno again to see what types of changes the exhaust hardware would make.

The first runs were made at wastegate spring pressure boost and an interesting finding came about: Stage2 boost creep is now much more manageable on the 15 STI! Boost does rise, but without the sharp rise starting at ~5500 RPM and in a much more linear and consistent fashion than the 2004-2014 STI's used to. Boost only rose to about 11psi while testing for creep and was still very responsive to WGDC changes at high RPM. The old cars frequently creeped higher and with less response to tuning changes.

Here is what boost control looks like on the WG spring with the TBE added:

As it turns out, there's very little power gain from the addition of the downpipe. I tuned the car to the same approximate boost level as some earlier Stage1 runs I had saved in the dyno (17.5psi) from last week's session. Here is what Stage1 and Stage2 look like, both at 17.5psi:

You can see in the boost and torque curves that spool is now faster by about 300 RPM, which definitely adds a bit of low end grunt, but once the turbo is "on", power is almost unchanged.

I raised boost a bit further to 18.5psi and cleaned up the tune a tad more and ended with this as the delivered tune on the car. With the extra boost (now at 18.5psi peak) we now have a nice torque increase over Stage1. The testing done on this car will help lead into potential Stage2 OTS packages for the 2015 STI:

After this test, it seems that there is still an airflow restriction lurking in the car. I've got some ideas on the data we'll be collecting next along with parts to try based on those results 



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