This was a great opportunity to test two turbos and find out which came out on top. To read the full article click on the link below the gallery.

The car is a 2004 Subaru WRX with a built 2.5L STI short-block and when the customer brought us the car for tuning we noticed the PTE-6262 (non ball bearing) turbo was a little laggy. Boost came up around 4800rpm to 25psi making 408whp by 6300rpm. Power was good but overall performance had a little to be desired! The customer decided the turbo needed to come on much sooner with sacrificing as little as possible up top so we came to a consensus that the Borg S256 would be the best solution.
The up-pipe and downpipe were remade since the PTE turbo had almost nothing in common with the Borg turbo other than the turbine footprint. Turbo oil feed and return lines were re-plumbed along with the wastegate dump tube (didn’t even have one before), some new hardware and we were ready for the dyno.
We were expecting better-spool but instead of better we ended up with ultra-spool!!! The S256 (still a non ball bearing) came in around 3200rpm to 24psi delivering 1600rpm of increased powerband and making peak power of 379whp@6000rpm. Yes the car lost 29whp peak but gained 154whp@3500rpm and 210ft/lbs@3200rpm. The Bullseye Power .55ar stainless turbine housing made better use of the exhaust energy contributing the huge improvement in turbo spool and response. The 29whp peak we lost was almost unnoticeable and is partially attributed to the almost one less pound of boost and the increase in heat from the longer duration in boost as the intercooler was unable to keep the temps down by redline.

Just for reference as some people have asked…All STI’s are tested in 4th gear and since this WRX also had an STI gearbox 4th gear was used.

The Borg S256 provided the customer with exactly what he was looking for making this WRX an insane sleeper.

Which turbo won this test is up to you, but I’m sure everyone knows who we would say won.

Dyno Results, General Info