AntmanAndLittleDi
Proven Member
- 161
- 15
- Nov 12, 2014
-
Russell,
Kansas
We'e having a few problems with our car, mainly the turbo giving out (whistling with shaft play) and hunting a possible vacuum/boost leak. The car drives great, but it'll lose power (I'm assuming boost) at 4500-5000 rpms, buck, surge and never recover to push beyond that point. This is while driving, but just sitting in the driveway it'll rap 8k rpm without hesitation. We'll hunt the boost/vacuum problem, done it before, many times . My question is mainly regarding the choice of turbo versus the throttle body. We have a large spool 16g turbo that (without looking and I may be wrong) has a 62mm exhaust and an aftermarket BBK throttle body that is still at stock size, about 58mm. I'm curious about the offset size. Is it correct to create a little back pressure on the turbo like this? Or did I just kill the turbo by doing so? The turbo only has about 5k miles of moderate drive time on it. I'd like to get a N/A throttle body since they're at 60mm, but at the same time I can find a 70mm for $90. What setup should I be looking to accomplish? Back pressure it a little (like 62mm turbo exhaust and 58-60mm TB)? Or no back pressure (go with 70mm TB) at all? I'll also be researching waste gate and blow off valve sizes in the same manner. The bov recirculation line is also set to atmosphere instead of actually recirculating it, not sure if that could cause my problem? It's been that way since we bought the car 4 years ago, but didn't have this problem until recently. My only CEL is for the catalyst system (it's been removed but not deleted out of the ecu) and occasionally one for the fuel rail(?). It has the stock fuel system and injectors (450cc). I have NGK plugs that show signs of running lean, but my wideband averages 14.7 at idle and cruise and drops to 10.2 in pulls. I do have a few mods done, they're all posted in my journal. I'm mostly interested in the turbo/throttle body selection, but feel free to ask questions about the other problem at hand. I've read a few other posts on the problem and have a checklist of things to check, just figured I should make sure I have the right setup to begin with or all my checks will be worthless. By the way, I saw it once and can't find it again, can someone please post up the home boost leak testing kit? The one that you can build with a bike tire pump. Cause I have one of those! Lol