Power Pages: 2003 Subaru WRX

Owner: Josh Gould
Dynamometer model: Brainstorm's Dynamic Test Systems 4WD Dyno

DYNO 1: Baseline
Air temp @ 70 Degrees Fahrenheit

Baseline Horsepower: 270.5
Baseline Torque: 275.9

Pros: When it comes to the bang for the buck quotient there is no better car than the Subaru WRX. From the factory the Subaru is powered by a potent 227 horsepower engine that delivers every ounce of the power to the tarmac via a 4WD drivetrain. In factory trim the WRX can perform neck snapping launches by propelling itself to 60 mph from a dead stop in 5.3 seconds. Not only does the boxter layout offers excellent weight distribution but it also increases the Subaru's road holding capabilities. It's no wonder why thousands made the trek to their local Subaru dealer to pick one up for themselves.

Cons: Although the engine is rated at 227 horsepower at the flywheel from the factory there is a tremendous loss of horsepower through the WRX's 4WD drivetrain. In factory trim we were only able to register 180.2 horsepower to the wheels, an incredible loss of 46.8 horsepower through the drivetrain! So what better way to make up the loss with performance bolt-ons?

Dyno notes: Our tester was unfortunately filled to the rim with 87-octane gas. So we had to improvise. After educating the owner about the vehicle requiring 91-octane gas, we made our way to the nearest Autozone to look for some octane booster. We found half a dozen octane boosters that were available but decided to go with NOS Racing Formula.

DYNO 2: Turbo XS High Performance Boost Controller (HPBC)
Air temp @ 70 Degrees Fahrenheit
Temperature difference from previous run: 0 degree Fahrenheit

2000 to 3500 HP average: 2 to 5
2000 to 3500 TQ average: 3 to 8

3500 to 5500 HP average: 3 to 18
3500 to 5500 TQ average: 2 to 15

5500 to redline HP average: 6 to 28
5500 to redline TQ average: 4 to 20

Peak Horsepower: 191.4
Peak Torque: 161.9

Pros: Let's just say our owner was blown away on how "that little blue thing" (as the owner of the vehicle called the TurboXS boost controller) can increase the output of the engine by 25 horsepower. We were also pleasantly surprised by how well the TurboXS boost controller was able to maintain boost pressure throughout the entire rpm band. We did raise the boost pressure from 14 to 16 psi but the difference was realized from 5000 to 7000 rpm. Unlike the factory boost controller, where boost pressure would take a nose dive at 5000 rpm from 14 psi to 9 psi, the TurboXS unit was able to maintain the preset boost pressure throughout. That is why we were able to gain 28 horsepower and 19 lb-ft of torque at redline.

Cons: We can't see any drawback to the TurboXS unit unless your car is still under warranty and the dealer finds out you did the modification.

Parts include: Manual boost controller, Allen key to adjust boost and instructions.

Tools required for install: Needle nose pliers and 12mm wrench

Dyno notes: The TurboXS boost controller only retails for $129.00 and it was able to generate nearly 30 horsepower. What more can you ask for?

Install time: 10 min

DYNO 3: Injen Super SES Exhaust System
Air temp @ 69 degrees Fahrenheit
Temperatures difference from previous run: -1 degrees Fahrenheit

2000 to 3500 HP average: 1 to 3
2000 to 3500 TQ average: 1 to 4

3500 to 5500 HP average: 0 to 4
3500 to 5500 TQ average: 0 to 3

5500 to redline HP average: 3 to 10
5500 to redline TQ average: 3 to 4

Peak Horsepower: 200.6
Peak Torque: 162.7

Pros: The Injen Super SES system is a very nice system with robotic TIG-welding and mandrel-bent piping. The flanges are all CNC machined, embarking on a true, high quality system. All the components are polished to a shiny finish. The Injen system was bolted on without problems, generating a unique tone from the boxter engine. Not only did the system look good on the Subaru it also paid dividends on the dyno, generating an additional 9.2 peak horsepower. We noticed the WRX engine was boosting slightly higher than the stock system due to the freeflow design of the Injen unit. Our datalogging of the boost pressure showed an increase of 0.5-psi higher than the previous run without the Injen exhaust.

Cons: The Injen system is not 50-state legal so for those who live in areas with strict law enforcement, the polished stainless-steel muffler will be a dead give-away to all the pigs out there.

Parts include: Stainless-steel muffler section, stainless-steel piping, two three-inch gaskets, miscellaneous hardware, stickers and instructions.

Tools required for install: 12- and 14mm wrench, 12- and 14mm socket, three-inch extension and ratchet.

Install time: 60 min

DYNO 4: Injen 3-inch Stainless-steel downpipe
Air temp @ 70 degrees Fahrenheit
Temperature difference from previous run: +1 degrees Fahrenheit

2000 to 3500 HP average: 3 to 5
2000 to 3500 TQ average: 8 to 16

3500 to 5500 HP average: 4 to 10
3500 to 5500 TQ average: 6 to 9

5500 to redline HP average: 8 to 20
5500 to redline TQ average: 8 to 10

Peak Horsepower: 218.7 Peak torque: 173.9

Pros: Like the exhaust system, the Injen downpipe is also a very nice piece of work. The collector is a cast stainless-steel section that is welded directly onto the three-inch, mandrel-bent stainless-steel piping. The flange is again CNC machined and robotic TIG-welded in place. The system fit perfectly, without any hang ups at all.

Cons: Removing the stock heatshield is a pain in the butt. You must remove the intercooler in order to remove the heatshield. In order to remove the heatshield there are (10) 10mm bolts holding it in place. Once the heatshield is removed the rest was a piece of cake. Be sure to soak the bolts with WD-40 before trying to remove them unless you like having stripped bolts.

Parts include: Three-inch stainless-steel downpipe, stickers and instructions.

Tools required for install: 10-, 12- and 14mm socket, ratchet, 10-, 12- and 14mm wrench, standard screwdriver and WD-40.

Dyno notes: This is what Power Pages is truly about, three products equals big power gains. We were able to generate an additional 38.5 horsepower and 18.7 lb-ft of torque from three simple bolt-ons.

Install time: 60-90 min

Conclusion
This is what Power Pages is truly about, three products equals big power gains. We were able to generate an additional 38.5 horsepower and 18.7 lb-ft of torque from three simple bolt-ons. Where the WRX would fall off in power previously, the EJ20 engine now really shines. Instead of having to short shift the gear to be in the sweet spot we know can smash the accelerator until redline. Not only does the Scooby sound better, it also runs like a champ.