What better way to present the Subaru page than in the classic World Rally team fashion.
From experience, the 2006-2007 WRX has proven to be a great all around play toy with incredible drivability, handling, durability, and power from its 2.5 Liter 4 cylinder Boxer engine. The quick spooling low RPM power is excellent on the street, but it was time to give this car wider power band and smooth the power in the cruising area. This write-up will also include differences between the GrimmSpeed up-pipe and an easily affordable Ebay purchased up-pipe.
After looking for a turbo to satisfy Tim's request to keep some amount of low end power for road race style driving, Majestic Turbo in Waco, TX (site) was again able to provide TurboFreak.com with this IHI VF22 ball bearing turbo for a great price.
a look at the VF22 turbo compared to the stock TD04L turbo.
The VF22 is said to flow 490cfm at 18 psi which is quite a leap over the stock TD04L turbo. The large P20 turbine housing (shown below) is a great increase for gains in upper RPM flow which increases horsepower capabilities. Since this turbo was installed on a 2.5 liter engine spoolup is not a problem and this engine could stand to loose a little horsepower in the low RPM range over the stocker turbo.
The power difference between the two is to be expected. The RPM band
is much more broad with greater acceleration from 5000 to 6000 RPMs
where before it would have a short heavy rush of torque then fall
off significantly as all micro sized turbos react. The smoothness
of the power and constant upper end pull completely changes the personality
of this car which makes drivability much better on the highway and
the city streets.
Above are photos of the black heat coated GrimmSpeed up-pipe and the cheap Ebay bought up-pipe attached to the VF22 turbo. As always, I will review only facts and previous experience with similar information revealed in past research.
pipe looks shiny and is very affordable, though the stock up-pipe specs
maybe better to use for faster spool up. Low end and upper
end may both be affected by common issues which affect velocity and
As you see, the
turbine housing is intrusively hanging inside of the flow area.
We must also realize the larger inner diameter pipe is so much more
volume to fill before velocity of expanding exhaust gasses take
effect to start the turbo spooling.