RallySport Direct’s 2015 Subaru STI (401hp 371ft/lb) Cavalli Stage 3 Turbo


Our 2015 STI has been a blast to build and tune, we had a goal in mind for this car on the stock block and we are pleased to say we hit it. At 400WHP the car is an absolute beast. There was room for more but we wanted to keep the car safe and reliable. Our build focused around keeping this a fun yet aggressive street car with the ability to go to the track, auto-X, or drag. We tried to focus on a nice broad power band and with the tuning done by Chris Haag using the COBB V3 ACCESSPORT , we were able not only reach our goal, we did it while keeping the car safe and fun to drive in any condition. We will continue to build this car just to see what it can do so stay tuned!


Event: Dyno Tune/Product Testing

Location: ZipTie Dynoworks, Salt Lake City Utah

Ambient Temp: 30-35F

Ambient Pressure: 12.7psi/86kPA

Elevation: 4600ft

Weather: Overcast

Car: 2015 STI

Tuner: Chris Haag

Dyno Info: Mustang

Transmission: 6spd

Gear: 4th

Peak HP at RPM 91 Octane: 352.1WHP @ 6213RPM. Corrected

Peak Torque at RPM 91 Octane: 315WTQ @ 5466RPM. Corrected

Peak HP at RPM 104 Octane: 401.4WHP @ 6272RPM. Corrected

Peak Torque at RPM 104 Octane: 371.2 WTQ @ 5228RPM. Corrected

Baseline hp/tq for Stage 1 on same dyno: 249HP and 269 TQ

Target Boost: 24 PSI

Target AFR: 11.2

Fuel: Sunoco 104 Octane with 10% ethanol and 91 Octane Pump Fuel


Modifications (Click on the links below for more product info and photos)


















  1. fdragon79says:

    What did the wheels do to the car? I believe the stock wheels are 18×8.5 +50 or +55…….. How did the driving characteristics change? Is it better or worse? Did you do something else to the suspension and steering components to allocate for the change in wheel size? Or did you change suspension/steering components and as a result you change the wheels?
    Any help on this would be helpful since I am planning on buying whees for my 2015 STI when I get it.

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