Can't stop boost creep on 6262 w/ AMS turbo kit
I had similar problems with the ams turbo kit when David Buschur was tuning my car on AEM. I think it has to do with their turbo kit design or the wastegate spring or even your boost controller
Jackpot!!
Running 20-22psi spring + boost controller normally causes a bit of creep.
Run the wq directly from a boost reference point (compressor/bov) and the curve will be flatter.
You can increase response/make the boost spike 1-2 psi by adding another foot or so to the vacuum
hose.
Before you spend a few hours taking everything apart give this a shot.
Last edited by 4kinboost; Oct 22, 2009 at 07:43 PM.
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From: Portland
Just a heads-up ---
Experienced the same boost creep issue with a 6262 on the AMS manifold with a 38mm WG - The issue is simply TOO much air flow on TOO little of gate. Solution is run a smaller turbo or increase the size of the gate.
Jason
Experienced the same boost creep issue with a 6262 on the AMS manifold with a 38mm WG - The issue is simply TOO much air flow on TOO little of gate. Solution is run a smaller turbo or increase the size of the gate.
Jason
Interesting that this thread popped up. I just switched my 6262 with a .63 5 bolt hotside to a 5858 with a .63 5 bolt hotside. Went from no boost control issues to massive boost creep. 10+ pounds worth. I pulled it all apart today so I can port the **** out of the wastegate opening. From everything discussed here it looks like I was on the right track.
Wastegate opening from precision:
Wastegate opening after porting:
And here's the ported hotside from my old 6262 that was done by AMS. I had no boost creep issues from this one:
Wastegate opening after porting:
And here's the ported hotside from my old 6262 that was done by AMS. I had no boost creep issues from this one:
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From: Florida
It's been a while but I corrected this by changing the WG to a 44mm and by relocating the WG so it now comes directly off the manifold instead of the back housing. Not sure if both were needed but works extremely well now.
dang,that hole got opened up big time haha...ive seen this very problem..6lbs of spring pressure in a pte 39mm gate...boost was out of control...trying to tune on 92 octane,staright up to boost cut at 30lbs
I've tried everything I can think to stop my setup from creeping but its just not working. I was running a AMS 37r turbo kit, with no issues, but decided to go with a 6262 to increase spool up. The only changes made were GSC S2, buschur ported intake manifold, buschur ported TB, and 6262 w/ a .63 hotside.
The backhousing I received did not have a wastgate port. Called Precision and they gave me the hole size and I had a machine shop drill the hole. Put everything back together and slapped it on the dyno. Boost creep , as high as 34lbs, was very bad so the tune was aborted.
Put in a call to AMS and asked what I could do to eliminate the creep. They said they heavily port the wastegate hole on their 6262 that they couple with the 850r turbo kit. I got it home and tore it back apart, ported out the turbo to match the port job on the 37r. Got it all back together, it seemed a little better but it was still boosting out of control.
Got in the dyno early this week but still cannot stop the creep. We were able to get it stable at just 20lbs of boost, but anything higher and it becomes very unstable.
Any ideas?
The tuner seems to think its the placement of the wastegate on the AMS turbo kit. Most kits Ive seen place it off the exhaust manifold, yet this one comes directly off the hotside of the turbo.
Im running a 38mm wastegate with like a 22lb spring.
The backhousing I received did not have a wastgate port. Called Precision and they gave me the hole size and I had a machine shop drill the hole. Put everything back together and slapped it on the dyno. Boost creep , as high as 34lbs, was very bad so the tune was aborted.
Put in a call to AMS and asked what I could do to eliminate the creep. They said they heavily port the wastegate hole on their 6262 that they couple with the 850r turbo kit. I got it home and tore it back apart, ported out the turbo to match the port job on the 37r. Got it all back together, it seemed a little better but it was still boosting out of control.
Got in the dyno early this week but still cannot stop the creep. We were able to get it stable at just 20lbs of boost, but anything higher and it becomes very unstable.
Any ideas?
The tuner seems to think its the placement of the wastegate on the AMS turbo kit. Most kits Ive seen place it off the exhaust manifold, yet this one comes directly off the hotside of the turbo.
Im running a 38mm wastegate with like a 22lb spring.
Last edited by BURNALL_4; Feb 14, 2013 at 08:59 AM.
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From: Florida
You should probably have a 44mm gate. I would start with that. The more exhaust you can get out the less chance you have of it creeping. I'd have a 44mm flange welded on go with that. i'd be willing to bet that will fix it. you might also be able to change the angle on how the exhaust flows into the wastegate. making it an easier path may also help.
Thought I would give an update. I got everything back together and took it out to test. The issue is resolved. No boost creep. I'm still using a 38mm gate so I'd speculate that moving the wastegate location and providing a larger escape opening for exhaust gasses was the fix in the original case.
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