Hey there everybody I am new to this forum and I am also new to the Subaru world.
I just recently bought an 02 Wrx that is somewhat fully built and that is still on a stock turbo.
The car has CP Pistons, Eagle Rods, Eagle Bearings, ARP Head Studs, 03 Heads, Koyo Radiator, Aftermarket Crankshaft and much more done to it. The built motor only has 6,000 miles on it and it runs great. It is tuned from my knowledge by the Cobb Tuning accessport that came with the car.
I had noticed a leak coming from the exhaust manifold flange and I replaced it yesterday. I got in the car, took it out and drove it and it runs great and the turbo comes up at lower rpms probably around 2500. But I'm not sure if the guy that had it before me might have had it tuned when it started leaking because when I first go it the turbo would not come in til around 4800. Now that I fixed it I am experiencing problems up top.
The turbo is almost lagging in and out between 4000 and redline, It will spike then go back down over and over again in 4th gear. I'm not real sure what to do. Maybe a re-tune? Or maybe a bigger turbo?