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BOOST CREEP! Im stumped & I searched.

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katchup

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Discussion starter · #1 ·
Ok i have been geting ready to race the fianl race of the year, which is sat. I recently got 650's and SAFC2 installed about 2 weeks ago. I had the best tuner in ID tune my car. During the tune all was good. We got a half decent tune at 17psi with no creep. But during the process we blew an IC pipe. So we called it a day. A week goes buy and i fix the bead on the IC pipe to prevent it blowing off. I go back and we start to tuning again at 17psi. During the week i was getting the IC pipe fixed. i touched nothing but the IC pipe. And now my boost is creeping all the way to like 24psi. I have had no problem creeping ever with this car since ive owned it. Some say its the 3" turbo back, but still ive never experienced boost creep, until today. What would be causing it to boost creep out of no where? Im trying to get my first race ever done in this car, and now this happends. I chaecked all the vac lines coming too and from the WG, MBC, BOV and they all looked fine.
Ive been running these mods and setup for about 6 months(minus 650's and safc2) with no creep at all!!!!!!!!! WHY NOW IS MY QUESTION?

MODS
ported out EVO III 16g, XS-power FMIC, short route IC piping, Greddy RS BOV, Hahn 3" o2, Hahn 3" down pipe eliminating the cat, 3" thermal R&D cat back, ported stock manifold, walbro 190, AFPR w/liquid filled gauge, injen intake, K&N FIPK, hallman pro MBC, brand new OEM tranny, ACT2600 clutch, under the hood shift kit, short shifter, autometer cobalt boost gauge, 1g black-top CAS, SAFC2, FIC650's, pocketlogger

thanks
 
#2 ·
It's definitely not your 3" exhaust, especially since the problem came out of nowhere. I could see that happening if something happened to the cat, but you don't have one. If you're sure it's boost creep and not boost spike, then I would say it's a problem at the wastegate, not letting enough air out and thus causing a slow buildup there. One possibility is that nothing suddenly went wrong, but instead maybe you had a leak at the IC pipe before it blew. Maybe that leak was allowing enough boost out and now that you fixed it you've got creep. I don't know, just a theory.
 
Discussion starter · #3 ·
Ya i know its creep for sure....goes to 17 and sits tehn it slowly creeps to like 24. Its pissing me off, Its out of no where. Maybe it was at the IC pipe. But i did boost leak tests and never noticed it leaking form there.
 
#4 ·
Maybe with the new injectors and the SAFC settings you're running too rich, especially in the higher RPM's, causing a higher exhaust volume to start backing up. It would be a higher exhaust volume no matter what because you're getting more combustion anyway. I know you said it worked fine in the first tune with those items, but still, that was only one try. I can't really think of anything else. :confused:
 
#6 ·
No way it's the 3" exhaust. I have a 3" exhaust and I even still have a high-flow cat in mine, and I can get steady 23 psi with pretty much the same setup as you (evoIII 16G, 660's, SAFC2, etc.) Only major difference I have is a 255 pump rather than 190, but that wouldn't have anything to do with your creep problem.
 
#12 ·
ok, the mbc has a two small hall on it 1 blow and one vacuum, the one that blows, blow on it and find out see if its really hard to blow on it, first when u blow on it, its kinda easy but right when you blow hard you'll feel the tightness...when vacuum clog boost creep happen
my english is sucks but i'm tryin to help u out man.
I hope u understand what i'm tryin to say
 
#14 ·
Sometimes the ball/spring in the MBC gets stuck. If you have a homemade type of MBC, unscrew it and pull the ball/spring out.

If that is not the case then you can also check the vacumn hose going to the wastegate actuator. It goes from the side nipple of the mbc to the wastegate actuator. Usually ive noticed that that hose gets pinched because of the intake pipe.

It cant be anything too complicated. :)

Nomie
 
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