Intense boost fluttering at WOT *updated with pics*
 

I have had my car back together for about a week now, and i've been slowly adding boost back in, I started at about 14-15psi and slowly turned it up to about 20, but after the last time I turned up the boost (to 20) when I'm at WOT the boost fluctuates rapidly between about 15-20psi, just shoots back and forth real fast, what could the problem be? I think it has like a 6psi spring in it, its a knockoff external wastegate, could the spring be too small for the amount of boost i'm running?

Re: Intense boost fluttering at WOT
 

try a bigger spring...pretty sure the rule of thumb is not to go over double the spring

Re: Intense boost fluttering at WOT
 

your mbc working properly?

Re: Intense boost fluttering at WOT
 

I will try a bigger spring, the MBC is homedepot style but has worked great until I went past 18psi.

Re: Intense boost fluttering at WOT
 

I def. agree, I'd say get a 14 psi spring and go from there

Re: Intense boost fluttering at WOT
 

Same thing happened to me with a 6 psi spring. I changed to a 14 psi spring and it's all good now :6

Re: Intense boost fluttering at WOT
 

sorry to bring this thread back but the problem resurfaced.

I put a 1 bar spring in it and boost holds rock steady at 15psi, now when I turn the boost up (still my homedepot mbc) it still flutters like crazy between 15-25psi. I just purchased an electronic boost controller but its not here yet so we'll see if that helps.

Re: Intense boost fluttering at WOT
 

Post a picture of your wastegate installed on your manifold. I've seen this with some "orientation" problems.

Re: Intense boost fluttering at WOT
 

does it sound like this?

http://www.youtube.com/watch?v=nCj6Spwl1CU

Re: Intense boost fluttering at WOT
 

Seems like this is what you are describing what size turbo are you running?

Re: Intense boost fluttering at WOT
 

sorry for not replying and thanks for the replies I did get.

It does not sound quite like that skyline, although it does kinda sound like a true compressor stall, but it happens very rapidly and gets worse as the boost pressure rises. I found 2 cracks in my turbine housing so its being sent to blaast for a warranty claim, since the crack was pretty bad, I found it less than a month after getting it back from the "rebuild".
blaast didnt think this would cause any problems and say's its "normal" which it may very well be but I'm just wondering if any of you have seen theese cracks before and/or would it cause me funny boost issues?
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Re: Intense boost fluttering at WOT *updated with pics*
 

ive seen small hairline cracks on old turbos that are normal and dont cause any problems but yours look pretty bad but im not a turbo expert

Re: Intense boost fluttering at WOT *updated with pics*
 

it looks like it gets bigger as it ascends into the throat of the turbine housing

Re: Intense boost fluttering at WOT *updated with pics*
 

It can't help..

Re: Intense boost fluttering at WOT *updated with pics*
 

Cracks start forming in turbine housings after they get a few miles on them. It's really common.

I doubt that's what is causing your problem.

Re: Intense boost fluttering at WOT *updated with pics*
 

im willing to bet its the ghetto mbc

Re: Intense boost fluttering at WOT *updated with pics*
 

He posts pictures of some irrelevant ----, but not the pictures I asked for. He's just wasting everyone's time.