shadowdawn

This happens on occasion as soon as I let off the throttle. I'll be boosting a few psi and when I let go of the gas it sounds like a fan hitting something or a quick spin down. I have been adjusting the vortech BOV to loosen it a bit (thinking that its not relieving pressure like it should, revved it while in park and its shooting out air from the BOV fine. Any suggestions? comments? Could it be my compressor blade? exhaust blades? something else entirely? Just remember this doens't happen a majority of the time even at full boost, only mabye like 3-4 times in total since saturday.

rioninja

possibility that the bov is sticking??? Is the bov still releasing air when it makes the sound?

shadowdawn

Well the BOV doesn't make a pssss noise so I guess its not like the popular ones. When it's being reved while in park its releasing air all right, but the sound only happens when driving not revving at a stop.

I've been playing around tightening/lossening, and even when it was REAL lose like turbo is going but no power (cause its bleeding all the air off) the noise still happens. I have since tightened it back up a little bit.

Could it be the BOV sticking? one time we revved it real high in park and it almost made a spitting noise (the BOV) scared the crap outta me when my friend reved it like that. I was hardcore gaggin spew sound outta the BOV, not the nice pssssss sound

CovertFI

i can feel the turbo lag, when my bov is too tight, also when i open my sunroof i can really hear the turbo's spool noise and it goes down really quick when the bov is too tight. if you can try and listen to the sound it makes, and the feel.

shadowdawn

I'm way more worried that the sound I'm hearing is back flow cause my BOV isen't working sometimes and the blades gettin messed with when the throttle closes (when I let off the gas). My turbo lag is from stop till 3200rpm but I have a t3/t04e which is a pretty big turbo with trim exhaust size of .63 from what I hear.. (don't quote me on that)

fiebru1119

i've heard something like whats happening to you described as compressor surge... dont quote me though, but i heard a guy complainin bout his bov doin the same thing and thats what he called it

shadowdawn

Yse its a compressor surge, I took the BOV completely and drove around and letting off the throttle sudenly in boost and it didn't make the sound.

Is there anyway to fix my BOV? cause I really don't want to have to buy a new one. Take into mind I tried the loosest and tightest setting and NO psssss instead in both cases I get compressor surges

RGAZ

I got all you answers here:

1. Yes, that is the sound of compressor surge. It is bad.
2. Make sure the BOV vacuum line is connected to the manifold with a very short vacuum tube of diamter 3/16" or larger. The larger the better.
3. Make triple sure that the place you tap the vacuum line is big enough to handle the 3/16" tube.

If all this is true, then the BOV needs to be replaced.

Randy

Nfurno

I just recently started to hear the same thing (a quick spool down). I know my bov is letting out air becuz I hear it and its loud. I'm wondering if I should use a bigger vac. tube or find another vac. source. I'm also wondering if it is normal to get some back surge when letting off and not opening the throttle again, since the turbo is still spinning?

not so civic

i have a hks which uses a piston in the bore and not a valve like the greddy for example. don't know which one is in yours...when mine binds sometimes in the bore it surges. several times i have had to take it apart and clean it. i also had to chamfer the sharp edges at the piston side of the port of the unit. it was scoring the piston and making it not slide like it was supposed to. when it binds now though, i just put alittle bit of oil on the piston and it always frees it up to do it's job like it's supposed to...try checking to see if you have a piston or a valve...they are exactly what they say they are and then try what i have said to. hope that helps.

shadowdawn

Alright I took it off the car again and am applying wd40 to the spring line that pushes up to open the valve. I can force this valve open with alot of man power pressing on it, so it does open, I think I'm also going to oil the actual valve itself a little around the sides, in case thats whats getting stuck.

shadowdawn

UPDATE:

Just drove around with it on its loosest setting and I still get a surge when letting off the gas while in boost. This blows.....

1bar

This might be too late to post but i was reading on overboost and they said....well
"If you seal up the blow off valve too well, then you 'll experience compressor surge, which is a cool sounding "chitter" when you let off the gas. Yes, it sounds cool, but no, you shouldn't keep it that way. Just remember that the main idea here is to get a full 6-7 psi while at the same time avoiding comp ressor surge." so maybe u have to tighetin http://www.overboost.com/fpimages/57.htm

Aeka GSR

what about us without a BOV. I have the Greddy kit and am running 5psi. Is a BOV necessary at this level of boost?

shadowdawn

From what I hear a BOV is necessary for the turbo's life.

I already tried a REALLY tight setting on the BOV and a REALLY loose setting, both give me a chitter sound. The only time I didn't get the chitter is when the BOV was completely off and I was running no boost (to the engine) turbo whinned but never surged when I let off the gas in that case.

Does it matter that my deltagate is screwed ALL the way in, meaning the tightest setting possible while keeping the locking screw in place?