Blow off valve

[DALLAS C SHANK]

So I vented my BOVs to the atmosphere yesterday, but instead of the normal whoosh, is there any way to get the fluttering sound? Aftermarket BOVs??

 

[mmh64]

I'm not a turbo wizard by any means. This is the first turbo car I've owned and had it for less than a year. The way I understand it that fluttering noise is bad. The compressor wheel in the turbo pulsating. I don't know what causes it or how to make it happen. I may be wrong but before you do that please get some knowledgeable advice.

 

[DALLAS C SHANK]

It may be. I was under the impression that it was the BOV. My buddy has a VW GTI that has an aftermarket bigger turbo on, and his does it everytime he lets of the throttle, hence my thoughts on BOV...

 

[mmh64]

I wish I could help you more. I just don't know much about it. Could be improper aftermarket bovs selection that may cause this. Too much pressure on compressor wheel causing surging? In any event, do some thorough research about bovs specific to your car to find answers first. Then do the mod. I would hate to see you wreck your turbos for a cool sound. What VW owners do to their cars may not work for ours. Please post any enlightening information you may find on this. You may even save your buddys turbos if in fact fluttering is bad. Again, I'm not the expert. I may be way off base here.

 

[SHOdded]

Aggressive tunes will cause the flutter/surge as well. Browse through the F150 forums to see for yourself.

 

[SilverSH0]

It may be. I was under the impression that it was the BOV. My buddy has a VW GTI that has an aftermarket bigger turbo on, and his does it everytime he lets of the throttle, hence my thoughts on BOV...

Most likely his BOV is too small or not properly adjusted for his larger turbo.

The fluttering noise is not good for your turbo. Do some Google searching on compressor surging as that's what it's called.

Basically when you're in boost the turbo is pressurizing the air to push it into the engine. When you suddenly let off the throttle, the plate closes and abruptly stops the air from flowing through your throttle body. Due to physics and momentum, the turbo is going to continue to spin after the throttle plate is closed. Since the plate is closed the air has nowhere to go and the pressure forces the air backwards through the compressor wheel. The spinning wheel "chops" at this pressurized air and makes that fluttering noise.

The BOV is designed as an escape for that pressurized air. So once the throttle plate is closed suddenly, instead of the air going backwards through the turbo it vents out the BOV. On your buddies VW, if the BOV isn't venting enough pressurized air fast enough it will result in compressor surging and give the fluttering noise.

That's a pretty quick simplified overview of the issue.

 

[madtown]

I just vented mine to atmosphere but would like more "woooshh" sound, I have been looking at aftermarket bov but cant find a replacement for the SHO. can I use the same as the F-150?

 

[13blacksho]

Who will be the Guinea pig???