2008+ Subaru Impeza STi Parts You Need

Something’s been getting in the way of my blogging: life. For now, here’s some bad ass parts you need to have for your 2008 and newer Subaru STi:

Cosworth S2D Dual AVCS 278°-10.7mm IN/274°-10.0mm EX Camshafts


Ian and I validated these ourselves on the engine dyno at Cosworth. Both power tests were done under the absolute same conditions: atmospheric conditions were DIN standard, boost=2200mbar (17.4psig), stock Subaru crate engine (with stock cylinder heads), Garrett GT35R turbocharger, 3? exhaust, TiAL 44mm wastegate, 100 octane unleaded fuel, RC Engineering 1000cc injectors, stock intake manifold, stock throttle body, dyno air to water intercooler, Cosworth ECPro ECU. We tested the cams this way because we thought it would be a pretty “real world” combination of parts. Yes we have the benefit of 100% controlled conditions (you can never really have this with a chassis dyno), a big ass dyno intercooler, and a free flow exhaust, but this allows us to compare cams vs. cams with no other BS restrictions in the way. As you can see, horsepower and torque is made EVERYWHERE. The gains at 7000rpm are astounding considering it was a stock engine: +45.4bhp! This wasn’t a wussy 12 second chassis dyno pass either. The power test sweep (above sheet) on the engine dyno lasted 1 minute and 5 seconds. Click the title for more details.

Cosworth ECPro ECU

Are you trying to make big power on your 2008, but the stock ECU is holding you back (or taking about 12 years to tune)? Yeah that’s what I thought. Step up to a real standalone that not only runs the factory dash with the factory FHI CAN bus, but the ECPro can also log many of the factory ABS and Center Diff inputs such as lat/long G, brake pedal on/off, brake pressure, center diff slip, individual wheel speeds, and many other useful parameters. Logging and analyzing these parameters allow you to improve your lap times or ETs down the quarter mile for both driver analysis and suspension setup. The massive amount of spare inputs allows you to log external sensors too that you can add such as oil temp, oil pressure, exhaust temps (individual cylinders if you want), Lambda (air/fuel), pre/post intercooler temps, suspension travel, damper pressures, etc. If you’re planning on getting serious with the EJ257B and don’t want to hassle with wiring in a standalone or dealing with a standalone with iffy electronic throttle performance or no CAN BUS support, then the ECPro is for you. Click the title for more details.

Dusty from NNI Racing has an ECPro ECU in his car and has been finishing on the podium despite being 200whp down from the competition in the modified class at the Redline Time Attacks. Design Craft built and maintains the car. I just turned up the boost recently and enabled the anti-lag (bang bang WRC style) so look out for Dusty at a west coast time attack. Its also featured in this month’s DSPORT.

Cosworth High Volume Inlet Manifold (EJ257)


This plenum needs no introduction since we cannot keep them in stock. Tyler did a bad ass job designing this plenum. It makes power on engines that breathe well. The more power you’re making now, the bigger your gains will be. Don’t even bother with stock turbos (unless you want show points) or cars with heavily restricted exhausts or gay intercoolers. It’s funny how the forums and various blogs are showing test results of this plenum on weak ass cars that don’t need a high volume plenum (try uncorking the exhuast first guys). If you do have a weak exhaust or a gay intercooler, this plenum still does wonders at high RPM (6.5k+), but on cars with a good exhaust and proper intercoolers, this plenum makes ridiculous power. Tuners have been reporting back 20-30whp gains on 91 octane and 40-70whp gains on race gas.

We did a validation power test on the engine dyno at low boost. Dyno sheet on this one tommorrow.

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