Can't stop boost creep on 6262 w/ AMS turbo kit
 

OLD Thread: This issue was corrected by upgrading to a 44mm wastegate and rerouting the wastegate off the manifold, rather than off the backhousing.

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.

Call AMS again?. They said that they port the turbine housing on every PTE turbo kit they sell specifically to prevent this, specifically the wastegate hole on the 5-bolt outlet.

*edit* port it more I guess.

I spoke to them and they said to match the port job that was done to the 37r, which was also very heavily ported. I opened the hole up to the same size if not bigger than the 37r. I mean unless there is a fine line between not enough and just right, I wouldnt think the creep would still be this bad. I may just have to send it to ams but I really dont think there is much more they can do with it.

I have boost creep on my 3065 cast kit...but its only a pound or so

Mine wants to shoot up between 30-34. My target is around 25 on pump.

Damn, that's a lot of creeping.. **** mine would creep 4-5 psi when it was cold but I was only running 11psi.. The more power the less wastegate you need the less power the more wastegate you need. For instance on my setup at the power I was at I needed a 60mm wastegate or dual 44mm wastegates.

It very well could be the placement of the wastegate or not enough wastegate..

Just wondering if you are running it re-circd or wg dumped?

You need to check the wastegate springs in there.. Open the wastegate and see what you have for springs.. The 38mm wastegates boost creep already and you might be on too much spring..

Mike

Im not sure why AMS places the wastegate in that location. It just seems like it would not be as effective as if it were on the exhaust manifold.

It's dumped to atmosphere btw.

We tested the spring and it started to open at 22lbs. I would upgrade to a 44mm if I new it would fix it, but Im not sure why others arent really having any issue with the same kit and ewg.

Open dump tube doesn't matter.. If your not in full boost then the wastegate isn't open..

I'll bet it's the placement or wastegate itself. Both cause boost creep..

I was asking about the wg dump for another reason not that it would relieve his problem ;)

Fwiw - i run an older Shearer manifold and 38mm wg on my 35r which i believe runs the wg off an elbow more similar to the way the AMS kit is/was.

However i don't attempt to run mine at anything thing lower than 25-27 psi even on 91 oct for these reasons.

Well i apologize for maybe not asking this earlier but there may be your problem.. If i recall you have 2 blue springs in there.. the 2 stiffest.. You need to go back to a single springs setup.. I believe then you have a chance at running 25psi with you start at 14psi base pressure.. When i owned the kit, the car was on 35psi always minimum..

Pm me I have some other ideas..

Mike

Im about to say screw it and just run E85 and up the boost.

But whats weird is that I can 20lbs with no creep, and I would think the lower the boost, bigger the issue.