anyone know why there is a fluttering noise when im at about 35-4k rpms? it sounds like my intake is pushing out air. i've only gone to about 4000 rpms, an it does it. usually the fluttering does it at redline or at a higher rpm. mine does it under no load. any help is appriciated. thanks

 

probably the wastegate. at lower RPM's it cycles to keep the turbo from overboosting and at WOT, it starts to cycle again when you hit your target boost.

it becomes really obvious with aftermarket downpipes. You really only hear the fluttering in the car though...outside it sounds like turbo whine....like when a semi driving next to you gets on the gas.

 

so is that bad?

 

no, its normal. you just not usually hear it with the stock downpipe. just get used to it. some people adjust their wategate arm until the noise goes away...but then your WG doesn't work right...that noise means its doing its job...and you get spiky boost and power curves.

the stock downpipe has the WG port closed off...but in the bellmouth its open and has an shoots right into an "echo chamber".

you only hear the flutter inside the car..sort of sounds like a cricket in your exhaust....outside it sounds like turbo whine...like when you drive next to a semi and the driver gets on the gas...

 

when i had a bellmouth, it sounded like a lawnmower when i got on it. i switched to a divorced, and now it sounds like there's a leak when i'm about 0.01~0.03mpa. like paper hitting a fan. is that normal with the divorced?

 

probably what the WG sounds like through a divorced WG pipe. you'll hear it after you hit full boost, light throttle, and throttle lift-off.

 

wat about my intake pushing out air. thats what is sounds like an looks like. it sounds like the waste gate isnt working an pushing air back out. also, my blitz bov isnt as loud. i think it's a vacum leak.

 

I know this may sound strange but I get this same phenomenon happening from time to time on my sti. Ever since I added my PDE downpipe, it would do this once in a while...everything would be fine, then all of a sudden, this fluttering would happen...at the time, when I did not have my Cobb AP, I would just reset the ECU and it would go away...now, with my cobb, I just reflash it using the controller....try it...

 

I FIXED IT!!! all i did was adjust my blitz bov an now it works like a charm. go fig?