Hey guys got a mbc installed & runing at 21psi but every time it hits max boost it makes a fluttering noise then drops all the way down also on the freeway when i take my foot of the gas it makes a weird clunk noise. Its frustrating as hell it ran better before the mbc was installed. Ive searched & every one seems to say its the snorkel but i dont even have the snorkel i have an after market intake. Only mods i have are Aem short ram intake, tanabe concept g blue exhaust (still runing stock cat), walbro 255, Hks ssq bov, dejon mbc & greddy boost gauge.

 

the clutch noise i have noticed my self. It sounds like a hissss every time i put the pedel down to the floor.

As far as the boost is concerned i guess you should check and see if u have a boost leak or not if u do that could cause the car to run ruff.

are u recerculating your Bov?

 

I think you probably need a tune. Get a reflash or something.

 

Sounds like what mine did when I had a non-recirculating bov on it. It bogs down every time after you let off the gas. If you installed them at the same time, that is probably your problem, not the mbc. There is also some kind of stableizer you can get, but I dont know anything about it.

 

Just as a test, why not replace the HKS BOV with your old stock one, to see if that cures the problem?

 

Its just that the bov was fine before the mbc was installed? Ive checked it out & its not a boost leak i might get it tuned & see how it goes after that. Il also give the stock bov a go.

 

You say its not a boost leak, but have you actually boost leak tested it?

Raising the boost pressure can sometimes find a weak point in your system. Where it will only leak at "X" psi or above.

FYI, venting to the atmosphere IS A BIG BOOST LEAK on a MAF metered car.
Increasing the boost increases the size of the "leak", and also the variance in the cars expected a/f ratio, vs real a/f ratio. Meaning, raise the boost, turbo increases volume of air as well, you expel more air, your car injects more fuel (to cover the higher volume of air) and your a/f is worse than it was before.

:bangs head:

When will people learn not to vta on these cars...

 

VTA............NO!!!!!!!!!!!!!!!!!!!!!!!

why discharge/waste the air when you can recycle it....LOL

you can make your own boost leak test kit very easy. ACE hardware has everything you would need under 25 bucks........besides the air compressor..

 

hks EIDS is the name of it. if you must vent is your car tuned ? im new but getting the hang of this dsm thing

 

Try adjusting the BOV. It sounds like you might be surging. Although it should holw boost a lot better. Swap it out with the stocker and go for a quick run. Easy test.