370 PT88 only making 3psi on dyno
370 PT88 only making 3psi on dyno Ok, just had the truck on the dyno and it wouldn't make any more than 3psi. Wastegate never opened. I have already done a boost leak test on the cold side and its perfect. Already in talks with Josh for a rebuild or new turbo but want to see what others think too... Runs great out of boost...
Build is
370ci. 8.5/1
Stock 317s with patriot springs
228/228 .581/.581 114LSA
PT88
60mm wategate, 56mm BOV... Both JGS
4" dp that's about 5ft long
3" cold side with eBay intercooler
Pump 91 and meth
Got this "perfect working" turbo used on yellowbullet. I'm pretty sure it's the turbo but if you got another ideas or things for me to check please post. Thanks in advanced and thanks to Josh@KYTP for the quick call back and help!
Build is
370ci. 8.5/1
Stock 317s with patriot springs
228/228 .581/.581 114LSA
PT88
60mm wategate, 56mm BOV... Both JGS
4" dp that's about 5ft long
3" cold side with eBay intercooler
Pump 91 and meth
Got this "perfect working" turbo used on yellowbullet. I'm pretty sure it's the turbo but if you got another ideas or things for me to check please post. Thanks in advanced and thanks to Josh@KYTP for the quick call back and help!
Last edited by eviltwin_1987; Jul 15, 2011 at 12:16 AM.
I watched the BOV shut while on the dyno.
Also, i don't know how loud it would be but the tc78 on my other truck is like 10x louder on the dyno. It seems like once the turbo starts spooling, it just stays there.
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New motor or did you run it before? I'd pull a compression check, I had a EPP cam I got new that was ground wrong by comp, it was a TURD, would only make 4-5lbs. Did a compression check it was WAAAY down, swapped back in my old cam and it all came back and ran its butt off. Can you pull the filter/etc off so you can watch the turbo spin?
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If you have the wrong exhaust housing a/r for your combination it could be hard to build boost. I would discuss it with one of the turbo sponsors, could just need a housing change.
FWIW, I've seen this EXACT same problem on a local Camaro. I just remembered. He couldn't get more than 5psi from an 85mm+ turbo. And it was slow to build that. It ended up being a bad FMIC from eBay. It was clogged or something. He ended up pulling the IC and running no IC with meth inj and it had no problems building boost. Might be worth a check.
Man that is weird then. Sorry... at least you know where to look. Still might be worth checking for flow restrictions. Maybe a rag went down a tube when you were swapping turbos or something along those lines. Just a thought.
Thanks for all the responses. If I can't find the problem when I pull the turbo off I will triple check everything on the truck and throw on the gt76 I have and see what that does. I'll be kicking myself if it is the turbo
ok, just finished doing a compression check on the motor.... 148-150psi across the board. Does that seem right? I am having a hell of a time getting this exhaust housing off, adding heat will be the next step to getting this thing free!
Edit: Just saw you have a low comp. 370 sounds about right to me, it's gotta be the turbo...
For 8.5:1 compression it doesn't seem bad at all really, especially if it's pretty consistent throughout. Stock compression is 10:1 correct? That would make sense for the "lost" compression.
I had a similar problem on an old GSX I had a long *** time ago, it sounds stupid, but check your boost controller/reference line to see if it's got a hole somewhere, it took me about 2 weeks to finally track down the reason why my 30r'd car was only building 8 psi.
I had a similar problem on an old GSX I had a long *** time ago, it sounds stupid, but check your boost controller/reference line to see if it's got a hole somewhere, it took me about 2 weeks to finally track down the reason why my 30r'd car was only building 8 psi.