Power Pages: 2002 Subaru WRX Part 3

Owner: Import Tuner
Dynamometer model: XS Engineering Dynamic Test Systems Dyno

DYNO 1: BASELINE
Air temp @ 75 Degrees Fahrenheit

Peak HP: 196.6
Peak TQ: 204.9

DYNO NOTES: To make dyno testing, fair we set-locked the boost controller down to 16.5 psi to ensure most of the parts we're testing are not making more power due to increased boost.

Baseline Horsepower: 170.3
Baseline Torque: 177.9 lb-ft

PROS: We're finally on the verge of breaking the 200-hp barrier, and now we're ready to unleash a few other parts that require a little more know-how to install. By now it should be obvious we have an APEXi S-AFC to compensate for any additional fuel tuning to keep our engine from blowing.

CONS: So far we have an air filter, exhaust, Hyper Ground System, AFC, boost controller and front-mount intercooler. We are a little disappointed that we didn't break the 200 mark earlier. We feel the fact that we leveled the boost to 16.5 psi may be one reason we haven't broken 200, but, then again, we are still running all three catalytic converters.

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DYNO 1: XS ENGINEERING DOWNPIPE
Air temp @ 74 Degrees Fahrenheit
Temperature difference from previous run: 1 Degree

Peak HP: 201.0
Peak TQ: 197.0

DYNO NOTES: Before we put the car on the dyno we welded on our own O2 sensor bung to monitor the air/fuel ratio. Although we did lose 7.6 lb-ft of peak torque, we were able to gain much more torque in the bottom end, as well as pick up a few more lb-ft in the higher rpm.

2000 to 3500 HP: 8 to 16
2000 to 3500 TQ: 10 to 20 lb-ft
3500 to 5500 HP: -10 to 15
3500 to 5500 TQ: -10 to 14 lb-ft
5500 to redline HP: 2 to 10

5500 to redline TQ: 2 to 5 lb-ft

Peak Horsepower: 201
Peak Torque: 197 lb-ft

Part includes: Front pipe, mid pipe, two two-flange gaskets, four nuts and bolts.

PROS: The downpipe is laid out in a two-piece fashion, meaning the second and third cat can be removed individually if the customer still wants to salvage one unit. If you want maximum power, get rid of all of them. Since the third cat has an O2 sensor attached to it, the mid pipe incorporates an O2 bung to replace it.

CONS: Although a two-piece downpipe does give you the option to run either cat, I believe most people are going to get rid of both. Also, the unit is mild steel so rust could conceivably cause a problem.

Tools required for installation: 14mm wrench, 14mm socket and ratchet

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DYNO 2: XS ENGINEERING UP PIPE
Air temp @ 74 Degrees Fahrenheit
Temperature difference from previous run: 0 Degrees

Peak HP: 217.7
Peak TQ: 225.5

DYNO NOTES: Once again, we locked the boost controller down to 16.5 psi to eliminate any extra horsepower being produced by a spike in boost.

2000 to 3500 HP: 2 to 18
2000 to 3500 TQ: 2 to 20 lb-ft
3500 to 5500 HP: -6 to 16
3500 to 5500 TQ: -6 to 10 lb-ft
5500 to Redline HP: 10 to 20
5500 to redline TQ: 10 lb-ft

Peak Horsepower: 217.7
Peak Torque: 225.5 lb-ft

Part includes: Up pipe and lower gasket.

PROS: The up pipe is a direct replacement for the factory cat. The up pipe's main function is to free up the exhaust flow before the turbo. In other words, we're trying to get the most out of the turbo's flow at the same pressure.

CONS: Just like the downpipe, the up pipe is made of mild steel, but we were told a stainless unit will be in production soon.

Tools required for installation: O2 Sensor socket, 14mm wrench, 14mm socket and ratchet, extension and a floor jack to raise the engine.

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DYNO 3: XS ENGINEERING VF23 TURBO
Air temp @ 69 Degrees Fahrenheit
Temperature difference from previous run: - 5 Degrees Fahrenheit

Peak HP: 261.8
Peak TQ: 224.8

DYNO NOTES: This turbo kicks ass! The sacrifice on the bottom end was lost only in first gear; once you shift the car, the turbo is in its sweet spot. With the injectors now almost maxed out, our air/fuel was still extremely rich at 11.0 air/fuel.

2000 to 3500 HP: -20 to -4
2000 to 3500 TQ: -35 to -10
3500 to 5500 HP: 6 to 25
3500 to 5500 TQ: 0 to 40
5500 to Redline HP: 10 to 50
5500 to Redline TQ: 10 to 40

Peak Horsepower: 261.8
Peak Torque: 224.8 lb-ft

Part includes: Turbocharger, water line hardware, oil line hardware

PROS: The turbo comes complete with all water and oil line hardware. There are no modifications necessary to install the unit, so this makes installation much easier.

CONS: The design of the turbo forces a big sacrifice of low-end power, but it is all made back at higher rpm.

Tools required for installation: 17 & 14 wrench, 12- and 14mm socket & ratchet, slotted screwdriver, needle nose pliers.

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THE PARTS

XS Engineering front & mid pipes: $426.50
XS Engineering Up Pipe: $250.00
XS IHI VF23 Turbo: $1,199.00

MSRP Total: $1,875.50

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CONCLUSION
It took a while, but we were finally able to break in to the 200-hp range. And this session saw us not just breaking 200; we were able to break far into the mark, at 261 hp. Plenty of torque was also produced with 224.8 lb-ft. Once again, we did sacrifice some bottom-end power, but trust us, it was worth it for the increase in the top end.

Performance Chart
	HP Level	HP+	TQ Level	TQ+
Baseline	96.6	*	204.9 lb-ft	*
1 XS Downpipe	201.9	5.3	197.3 lb-ft	-4.6 lb-ft
2 XS Up Pipe	217.7	15.8	225.5 lb-ft	28.2 lb-ft
3 XS VF 23 Turbo	261.8	44.1	224.8 lb-ft	-.7 lb-ft
Final	261.8	65.2	224.8 lb-ft	19.9 lb-ft