Hey guys. I have a Evo IX. When I let go of the gas at very low rpm's (1000 to 1800 rpm) I hear compressor surge. Could this be something wrong with my bov, not opening? My current mods are, K&N cone filter with maf adapter, Megan dp, ttp tp, megan catback and tune. Any help will be appreciated. Thank you in advance.

 

Your probally not hearing surge. very unlikely. The flutter noise is normal for our cars is accually the bov opening but only slightly. I believe.. But every DSM and all two EVO's I have had all of them have had this nosie.

 

I see. It just scared me. It sounds just like compressor surge.

 

I wouldn't right it off.. if your BOV is releasing slightly like mac74 said, sounds like a boost leak. If you end up needing to replace the BOV though, I'd recommend sticking with OEM. The IX's came with damn good BOV's good for up to 25 pounds

 

The flutter is not a boost leak it opens slightly to release the unused pressure bulid. If the BOV did not open the you would have surge. There is not a boost leak. MY RVO was running 24 PSI solid to redline 7800. And If I part throttled and let of I would get the flutter noise you are hearing.

 

So I assume you have a good bit of boost built up when you let off at those lower RPMs to be able to hear it. My car does this, particularly when going up a steep hill in 5th gear. The car can build like 15psi under 2k RPM and then you let off to shift to 4th and you hear what sounds like surge.

This is normal. Many people have written about this.

 

I would do a boost test just to make sure everything is solid. never a bad idea.

 

you're driving the car wrong. you should never really be driving the car below 2000 rpms, even stock it's cammed too aggressive for that. I don't even understand how you would have any boost at that point and therefore how surge would be possible.

you're probably confusing the hell out of your wastegate?

 

Trust me there is boost that low. Not much but there is some. Especially if you eliminate the boost cut from the factory.

 

Thank you guys for your suggestions. Im sure its not a boost leak, but im still going to do a boost test, to make sure.

 

No problem all should be fine ..