Power Pages: 2003 Subaru WRX

Dyno 2: AEM Cold Air Intake
206.5 HP 193.9 TQ

Pros
AEM's Cold Air intake system is engineered for power. Many don't realize intake systems aren't just pipes with filters attached to the throttle body. They can be tuned with specific pipe diameters and lengths to add power in specific areas of the power band. In this example, we saw peak gains of 4 hp but lost 4.2 lb-ft of torque at the peak. Although the gains in the low-rpm range were negligible and we lost some torque at the peak, we gained as much as 12.5 hp and 13 lb-ft of torque between 6500 and 7500 rpm. As you can see in the graph, the stock intake's power drops off after 6500, where the AEM intake keeps the curve steadier all the way to red line.

Cons
Because the filter is located lower and away from the engine bay, it will get a colder air charge, but it will be susceptible to sucking in water. If you suck water into the clyinders, they will hydrolock. Don't be an idiot: If it rains, don't go blasting through puddles.

Notes
The installation was smooth and fairly straightforward. If you're a novice, take off the front tire so you can get the splashguard off to mount the intake.

Tools
8- and 10mm socket, extension, ratchet, pliers, and standard and Phillips screwdrivers

Parts
Filter, intake pipe, hose, hose clamp, instructions and decals

Temperature
Air temperature: 76.4 degrees Fahrenheit
Temperature difference from previous run: +7.6 degrees Fahrenheit

Installation time: 60 to 75 minutes

2000 to 3500 HP range: 0 to 1
3500 to 5500 HP range: 0 to 3
5500 to red line HP range: 0 to 12.5
Peak HP 206.5

2000 to 3500 TQ range: 0 to 6
3500 to 5500 TQ range: 2 to 10
5500 to red line TQ range: 0 to 13
Peak TQ 193.9

By Richard Fong

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