SoloRacer

Sorry, should have clarified. The car did not come with a BOV or DV when I bought it. However, all these videos were shot after I installed the Tial BOV.

SoloRacer

Duke: I'm not sure what you mean by the BOV being too stiff to open. Can you elaborate? In the video there are some supplemental sounds that are not BOV related. For example, on the in car footage the rattle you hear during shifting is actually a loose shifter - got to get that fixed. On the first outside run the car is spinning it's 315/35's when I shift gears.

rage2

I'm still waiting for a ride in that car SoloRacer...

DivineE

First I would just like to say that you have one hell of a car! I read the magazine article years ago and always wanted to see/hear more of that car. Awesome machine.. but if you read my previous posts on this thread you'll see what Duke is talking about. The BOV is not venting enough air (probably due to a stiff spring as I'm sure the Tial is capable of releasing an adequate volume of air) so that flutter flutter noise you hear is actually the surge of pressure bouncing between the turbo and the throttle body as it dissipates. If the BOV was working correctly you would hear one uninterrupted release of air. Easy to fix with the right spring though. You can buy a range of springs to match the boost pressure you are running

Duke

Solo, perhaps I went through the first clip a bit too fast, but in some cases it does not seem to open as Divine is writing above. I used a Tial BOV with the stiffest spring myself on my 968 turbo engine and it always opened enough to avoid any flutter noise.
Here's a short clip of how it sounded in my 968 turbo setup:
http://www.youtube.com/watch?v=18Nc49HrJX4

SoloRacer

Maybe this summer when I get confident enough to finally put it into Boost Map #3. *lol*

J1NX3D

i've never heard of the above described with 2 separate names for each type of circuit before. I've always known it as one item thats either plumbed back (recirculating) or not, but use of the name- recirculating valve, pop-off valve, BOV, DV- depending on whose forums I was reading (what market/country, genre).

JDS968

I've always heard one referred to as a DV [Diverter Valve] or sometimes recirculating valve, because it diverts the compressed air back into the compressor, thereby recirculating it without blowing any of it off to atmosphere...and the other one referred to as a BOV [Blow Off Valve] or sometimes pop-off valve, because it simply pops open to atmosphere, blowing off the compressed air without recirculating it anywhere. I've not really heard them used interchangeably, except sometimes by people who generically refer to them all as BOVs because they have never heard of DVs.

On the other hand, I haven't really conversed with a lot of people from outside the US on DVs and BOVs, so for all I know, it could be a regional thing.

And to make things even more confusing, some manufacturers (Forge, at least) are now making hybrid valves that can recirculate some of the charge air and vent the rest to atmosphere. I think they may even be adjustable, although I can't remember whether it's a continuous adjustment, or just 100/0, 50/50, and 0/100.

J1NX3D

ah k.

well, its kindof like external wastegates. you can vent to atmosphere with a screamer pipe (local term, same for you guys?) or plumb back into the exhaust a'la 924 & 944 turbo. I had just assumed that some BOV's were made to recirculate and some weren't and that somecan be adjusted to do either, like an external wastegate.