Turbo Flutter and Blow Off Valves

[orangeute338]

if I have my spring to tight(bov closed at idle) it doesnt even open at all when I back off....

[riptide]

As soon as I am on boost I can hear the control pressure to the BOV shut it tight and there is no more leakage til I drop off the gas again so I will leave it for now. I might get a big flashy BOV for those open bonnet moments later on

[riptide]

OK, I have made a new intake pipe and installed my big flashy 50m/m BOV. I stripped it down when I first got it because I thought the spring felt too strong. I was unable to easily push the plunger by hand. So after installation I fire up the wagon and the plunger moves ALOT easier than I thought it would. So easy in fact that I only have to drop off the throttle at very low acceleration and I get the rattle-snake noise every time and under more extreme conditions I have a bonnet full of rattle-snakes.

Is this normal?

Can it be changed easily to hold more (pressure, not rattle-snakes)?

If I get a stronger spring I may have trouble installing it.

Edited 16/07/11 06:46 AM by riptide

[Dillz]

Sounds like it's too strong still and not opening, a blocked bov will make that sound.

[riptide]

I can see it open with the hood up just revving it up and dropping my foot off.

[riptide]

maybe it's more of a flutter noise...I will have another listen tomorrow

Cheers Dillz

[XXXRTURBO]

I have never ran a BOV took it of pretty much first day for a bit of noise, and same thing on my previous ba didnt run a BOV and never had a problem not running it(had 270rwk). At the end of the day who cares its either u run it or u dont I just like the sutututu noise compared to the sh*t ricer wrx BOV noise that sounds IMO

[Dillz]

It's wierd I swear mine runs a tiny bit better with it blocked, even though it shouldn't. I know there's fark all lag with an auto anyway but still.

[spoolxr6]

The standard Bosch valve is not your generic BOV. It is an air by-pass valve. My old supercharged 4AGZE corolla also had one to bypass the vanes of the blower on idle so it wouldn't have to suck through the blower to breeth at idle. So yes it is possible that on idle with vaccuum applied to the valve it will open. Boost is applied on the diaphram to it to keep it shut.

[riptide]

Sounds like it's too strong still and not opening, a blocked bov will make that sound.

I had another look today when I got back from fishing and I think you may be on to something. If I rev it lightly I get the flutter sound but no movement to be seen from the BOV but if I give it a hard rev and drop back the Bov will pop open with a positive psshhh. I will drive it for a bit and see how it goes and then maybe lighten the spring. I'm getting a bit old to be a boy racer