Thread: Missing Boost
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Old 08-09-2013, 03:38 PM   #19 (permalink)
luigi90210
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Quote:
Originally Posted by Sh0velMan View Post
Hmm. My understanding of such things from my experience with my various F.I. cars, is that the BOV should be closed at all times, except when there is a pressure differential between the intake manifold and cold pipe, meaning the TB is closed but there's still boost in the cold pipe(s).

If it were open at idle, and you ran an un-recirculated BOV, you'd be sucking unfiltered and unmetered atmospheric air at idle...

I could be completely wrong though. Wouldn't be the first or last time.
i have always been told this as well, with a BOV you want to keep it closed until you let off the throttle which would release all the pressurised air and prevent compressor surge

with a BPV you can have slightly open at idle or completely closed because you are recirculating after the MAF so either way, you are taking in the same amount of air since its been accounted for via MAF

also there is no such thing as a recirculated blow off valve since a blow off valve, blows off the pressurised air into the atmosphere while a bypass valve, allows the compressed air to bypass the turbo/supercharger and is recirculated in the system, since internally they are the same, the set up ultimately determines what the valve will function as(IE remove the recirc hose from the BPV and you now have a BOV and vise versa)

if im wrong about anything though, anyone please feel free to correct me but afiak bov and bpv are the same internally, just depends on how it is set up
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