However, our system is pretty efficient at this power level and we like how the car looks reasonably OEM externally and under the hood. We do not want to cut up our front end for a big front mount intercooler and have a big cone filter sitting there when you pop the hood. I mean what’s the point of a stock position turbo? We do not want to add any more lag either. We think a flexible 500 plus whp is enough for a daily driver car of this size. We do think that this turbo is capable of another 20-30 whp with better conditions, bigger charge pipes, a bigger filter, and perhaps a bigger intercooler which is pretty impressive for a stock drop-in replacement turbo with about the same lag as stock. There are a few stock position turbos that might make more power but we found them to be pretty laggy. Our turbo makes more power and more area under the curve than many rotated mount setups we have seen.
For fun, we started looking at the power results of some other cars and we looked a lot at Z06 Vettes, the LS7 is the King of NA LS motors and is found on the Z06. Even looking at FBO and LS7’s with mild streetable internal mods, our little 4-cylinder makes more power and more torque with a much wider powerband. Our little Subie can give GM’s mighty Z06 the business!
We are pretty pleased with the results of our joint engine project with IAG and Precisisoion Turbo from both an aesthetic and performance standpoint. At this point, our Project STI is pretty close to being done. It is a very nice street car that can still easily hang on the track. It is an expensive sports car fast while not attracting excess attention. It’s well-balanced and good at cornering as well as braking and does not ride excessively harsh either.
Like most of our project cars, it demonstrates that an engineered, balanced approach to modding cars can yield pretty good results.
10 comments
Really enjoyed the read, very impressive results even on such a hot day, really liked your thought process on why not going for a bigger turbo for heat management reasons, very overlooked aspect on builds, one must use factory engineering for fundammentals like that, it´s very hard to modify that in a street car, thinking of stuff like that keeps you save from trouble
I would really love to see this car in person (not when I’m busy at Subiefest) and shoot the breeze with you. Maybe a ride-along on a freeway on-ramp?
The car is my daughter’s so it is not typically where I am
Excellent work on this. Any chance we can get some driving footage of the car showing boost threshold and response? *Asking for a friend.
Go to my daughter’s Instagram kurisuta.k I think she had a video of on-boost acceleration.
I’ll check it out. Also appreciate the video that dropped today. Thanks!
Thank you!
I’m slightly confused. Is this the second or third aftermarket turbo in the car? I’ve read the series multiple times and it almost reads as if the turbo was upgraded at the same time as the built engine went in, and then again (3rd precision turbo) for these numbers.
It is the second turbo, the first was the 55mm inducer one.
What is your impression of both the 55mm and 58mm spool wise? Can either make peak boost by say 4000rpm? I know that the 55mm fell off up top around 6500, but that isn’t bad for a stock redline type set up. Just wondering if this is a good street turbo on pump gas or if it tends to be a little lazy. You can message me directly if you like. Thank you for your time!