First off this ISN'T my car. It's a friend of mine. 2004 WRX with uppipe, turbo back exhaust, pinks, Ebay TMIC, GM BCS, Greddy RS bov and VF39. The car pulled HARD and SPOOLED like a banshee when it was tuned. Lasted for about 2 weeks and now it's spooling horribly slow. 17-18 psi at 4500ish rpms. Used to be at 3000-3200 full boost. Tonight we will be doing a boost leak test and then light seafoaming to see if there are any exhaust leaks. Checked the GM BCS lines and they are good and tight. I'm wondering if the BOV may be cracking open or if the turbo is just plain tired out. The turbo had the hairline crack that ALL VF39's tend to get so I doubt that is the issue. Any ideas what may be the culprit other than boost leak or preturbo exhaust leak? We did notice a bit of gummy oil (it was sludgy as in if it mixed with water) in the lines that run across the front of the TMIC.
i would assume a tear on the y-pipe or it not being seated. mine did that whenever the clamp on the compressor outlet worked loose.
Turbo is okay. The turbo inlet has a small tear on the bottom of it but that has nothing to do with spool but still needs to be fixed so Jason is ordering him a APS or AP hard pipe. We couldn't get the boost leak test to make more than 5 psi and I hand turned the engine a TON to make sure the valves were shut. Gave up on that and tested the turbo itself and it built tons of psi. Same with the IC. Then it clicked in my tiny brain......the hoses from the turbo and the the hose on the BCS itself were sorta loose. You could barely pull on the lines and they would slide off. I zip tied the hoses tight and reinstalled everything (IC and intake). Took the car for a spin and bam full boost at around 3500 rpms. Not the best but better than 4500 rpms. Jason did tell Doug to keep the car safe and save his tranny so looking at his dyno chart boost is on par since his full tq is at 3700ish.