I have a 03 Evo 8 with bolt ons and seems like I have a flutter problem.
low rpms and at full wot no problem with flutter but when im on partial throttle in boost (from 3.5k and up) my car seems to flutter until I back off or step on it.
I don't really feel it buck when it flutters, maybe slight.
my mods are intake, muse o2 dump, catless dp, catback, greddy bov, ets licp.
No known boostleaks, It was tuned at 25psi
Heres a video of the flutter and wot
http://www.youtube.com/watch?v=7Dc07...ature=youtu.be
Any inputs would be appreciated.
thanks

 

Is your bov greddy-Rs? if so, that's the problem.

Greddy-rs bov is known as 'arguably the best bov on the market.' LOL. No matter what you do, you will still have a problem.

If you search 'greddy bov flutter' on google, you will find a ton of thread.

 

When did this start happening? What have you done with the car since it started happening? Is the BOV plumbed up correctly?

 

Try going with a stock 9 DV and see if that fixes the fluttering issue.

 

Loosen the adjustment.


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You have a type S dont you ? That thing must be really worn out. Ive had the type S, Rs, and Even the R and they all suck on Evos, when I had my Srt4 the Rs worked perfect. Ditch it and get a Tial Qr or a stock 9 bpv.

 

Do you have a 3-port BCS?

 

Mine did the same. I took it apart and the diaphram was torn.

 

thanks for all the inputs
i have a gm 3-port installed
i do have a greddy type-s, came installed when i bought the car.
I'll be picking up a evo 9 dv, hopefully that gets rid of the problem

 

I have a Factory Evo9 mr metal BOV and even I'm having this issue ATM. Was going to make a thread on it, but I'd rather see where this one is going :P

 

searching through the forum, some people say its normal

"Partial throttle flutter. I think it's the mid way point between spooling like the bov is partially open to reduce surge. So basically step on it!"

"Gotcha. Just found some info that says part throttle/partial throttle fluttering is the valve compensating for pressure inconsistencies. It said flutter @ WOT is compressor surge"

is this true?

 

Also keep in mind that the 3-port will make a surging type of noise under boost because the solenoid is rapidly opening and closing to keep boost at the target psi.

 

But most likely is a problem with either your bov or wastegate. I would ditch the greddy and go with something more quality such as a tial. Also may want to check waste gate pre-load and make such everything is functioning properly.

 

replaced the greddy with oem evo 9 dv, got rid of the flutter! thanks guys!

 

I've got the same problem,needless to say it's worse now with the new turbo...
HKS Sq dump valve here,it's recirculating into the intake manifold.
Perrin 3-Port Bcs.Is this bad for the turbo or not? Because it doesn't really bother me,i've learnt to drive it on or off boost.