After getting numerous emails requesting a good bolt on upgrades for the WRX’s so they could ditch the TD04 for a better spooler. After a lot of searching and asking a few pro’s the most recommended and reliable option was the APS SR56. One thing was clear the WRX lacked top end power and the drives wanted a larger exhaust housing for a better power curve and APS built it.

The APS (Air Power Systems) S/R56 series of turbo is dual ball bearing, single entry, oil and water cooled turbocharger that is known as one of the best bolt on upgrades for the WRX STI, although its bolt on you will have to ensure you have the right oil & water lines as they differ between models.

A HP rating of 550 is a big claim when your not a very large manufacturer like KKK or Garrett, however if you search the WRX forums you will see few examples of 25psi by 4000rpm and STI’s hitting 500hp at 22psi with supporting mods. The element that stands out the most on this turbo is the wast gate, a Forge piston type actuator that is made from billet aluminum to higher temperatures.

When buy APS turbo make sure you choose the turbo that suits your application the best, while doing research I have seen one example of the SR56 being used as a stock replacement and only seen a 10hp gain on the dyno, that and also the S/R series are very similar in price.

RRP $3000

Tech Specs

Rated HP: 550