I saw a BOV on a Comptech S/C yesterday and I wanted to know what exactly that would do.. Anyone have any ideas??

I pulled up next to the guy on the highway and it was constantly going off or anything (I didnt hear anything besides the whining the S/C)

I thought it was interesting anyways.. does it actually work like a turbo BOV?

Chris

 

Now that's interesting ... I've never heard of a BOV for a supercharger.

 

Actually the Comptech SC comes with a BlowOff Valve though I believe it's setup to operate a little differently then in a turbo setup. It's vacuum operated and setup to do 2 things. Under high turbine speed(high boost/RPM) and high intake manifold fold vacuum(closed/low throttle) it opens up and provides a place for the unused high pressure air to go. At lower turbine speeds(low boost) and high intake vacuum it opens to provide a secondary (low resistance) air supply to the throttle body.

I have never heard this BOV in operation and i dont think its designed to make alot of noise.

 

While i've never heard the Comptech unit operate, i have heard others such as HKS or Blitz...some just operates, some let people within a 2 mile radius know you have a BOV...

 

Comptech uses a By-pass valve (same P/N as Audi and Porsche I believe) to keep the compressor from stalling in high manifold vacuum situations (like davepk said).
The thing that sucks is that it recycles the hot air back around to the intake side of the blower continuously during idle and cruise.
I've vented mine to atmo but you can't hear it (BOV style) unless you really listen for it (you can get away with this on our cars since the ECU doesn't try to keep track of all the air, a la MAF systems). I will have to clean my air filter more often though

 

RT... Have you placed a one way valve on the output of that bypass valve? If not you may be sucking in unfiltered air. According to Shad thats why they have it tapped upstream of the compressor and down stream of the filter. Unfortunately that also results in the recycling you describe but since it only happens under high vacuum its apperantly not a problem.

question.. Is a bypass valve distinctly different then a BOV? Are there setups were both are part of the system?

 

Dave, I have a small air filter on the end of the tube but for an entirely different concern. The tech inspectors tend to get a little freaky when they see tubes ending in the middle of nowhere, so I put it on to avoid the situation.
As far as air going backwards through the by-pass valve is concerned, the only situation I can think of where this might happen is if the drive belt gets thrown (not like that's never happened, Keith? you out there?). However, I guess I'm covered either way.
Here are some pics:
2nd pic has end of tube with filter pulled up for your viewing pleasure