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2015+ WRX FA20 Mod Guide

We did some testing on our 2016 WRX  here at our shop and wanted to share the results with you guys! This was a completely stock FA20 WRX and we did 4 stages of modifications from stock and kept track of the results to compare. All of these results are uncorrected numbers which are about 25% lower than you would expect to see on a Dynojet dyno or our “Shootout” numbers. For more information on comparing dyno numbers check out our dyno page.

Our starting point was completely stock. With no tuning, no modifications, and with 91 octane fuel.

This vehicle made 180 HP and 210 TQ on our Dyno at 15psi tapering down to 10psi by redline.

Below you find the information of our findings along with dynographs for comparison. If you have any questions about building your 2015+ WRX , give us a call (763) 316-5882.

Stage 1 vs Stock

This included the Cobb Accessport and no modifications on the same fuel as our stock vehicle. This was a custom tune by us with no modifications.

This stage we made 202.5 HP and 241.5 TQ on our dyno. We saw a 21 HP or 12% increase in peak HP and 32 TQ or 15% gain in TQ over stock. We were able to get a good 10-20 HP increase through the whole powerband.

Stage 2 vs Stock

This included the same fuel from our stage 1. We removed the 2nd restrictor pill and added a Grimmspeed J-pipe and Intake.

This stage made 232.0HP and 252.1TQ on our dyno. With stage 2 we found a 52HP or 29% increase in peak HP and 42TQ or 20% gain in TQ over stock. We saw gains throughout the whole powerband increasing to a maximum of 81HP at 6300rpm. You can expect 5-10hp more on 93oct.

Recommended J-Pipes

  • Grimmspeed
  • Cobb

Recommended Intakes

  • Grimmspeed- This intake functions the best from car to car. Other intakes can read differently simply by installing the air filter in a different location then the original spot.

Stage 2+ vs Stock

This included the same items and fuel from our stage 2. Additionally we installed a Grimmspeed electronic boost controller, Grimmspeed charge pipe, and most importantly a Grimmspeed intercooler.

This stage made 250 HP and 265 TQ on our dyno. With stage 2+ we found a 69 HP or 38% increase in peak HP and 55 TQ or 26% gain in TQ over stock. Upgrading the factory intercooler to a Grimmspeed intercooler is one of the best modifications you can do on these vehicles. With the factory intercooler we were seeing manifold temps peaking between 130-150 deg F by 6500 RPMS. With the Grimmspeed intercooler we commonly only see 5-10 deg increase compared to the 30-50 deg we see with the stock intercooler. This was nearly 30 HP increase from the Grimmspeed intercooler.

Recommended J-Pipes

  • Grimmspeed
  • Cobb

Recommended Intakes

  • Grimmspeed- This intake functions the best from car to car. Other intakes can read differently simply by installing the air filter in a different location then the original spot.

Recommended Intercoolers

  • Grimmspeed TMIC or FMIC
  • Cobb TMIC or FMIC
    • Some of the less expensive intercooler kits don’t actually function much better then the stock one so its always a good idea to do research before purchasing a intercooler. Also if a TMIC doesn’t come with or have the option to get a hood splitter its probably not that good.

Recommended EBC 

  • Grimmspeed

Stage 2+ E60 vs Stock

This included the same items as our stage 2+. Additionally we added a Cobb flex fuel kit,  Detsch Werks fuel pump, and put the vehicle on 60% ethanol.

This stage made 310 HP and 305 TQ on our dyno. With stage 2+ E60 we found a 128 HP or 71% increase in peak HP and 89 HP or 42% gain in TQ over stock. We purposely keep the wheel torque around 300ft/lbs to help protect the weak rods in these engines. We saw gains of around 80 HP at 3500 RPMS climbing up to around 150 HP at 6400 RPMS over stock. We saw about 60 HP in peak power from stage 2+ to stage 2+ with E60 with no changes in boost.

Recommended J-Pipes

  • Grimmspeed
  • Cobb

Recommended Intakes

  • Grimmspeed- This intake functions the best from car to car. Other intakes can read differently simply by installing the air filter in a different location then the original spot.

Recommended Intercoolers

  • Grimmspeed TMIC or FMIC
  • Cobb TMIC or FMIC
    • Some of the less expensive intercooler kits don’t actually function much better then the stock one so its always a good idea to do research before purchasing a intercooler. Also if a TMIC doesn’t come with or have the option to get a hood splitter its probably not that good.

Recommended EBC 

  • Grimmspeed

Recommended Flex Fuel Kits

  • Cobb
  • Delicious Tuning- The delicious kit can be optioned with a LPFP (low pressure fuel pressure) sensor. With this sensor you can monitor LPFP on the Accessport and the Delicious kit will signal the ECU to put your tune into a limp mode if LPFP drops below ~35psi.

Recommend Fuel Pumps

  • DW 65c or 300c
  • Nostrum HPFP (high pressure fuel pump)- This is not needed for flex fuel but gives you the ability to run full E85 so you don’t have to mix down every time you fill up.
Have Questions? Call Today!
(763) 316-5882