Originally posted by Dustyn:
The BOV is before the MAF so its not unmetered air. When the car is idling its in full vaccum 19hg.

So in full vaccum you have the BOV diaphram being sucked up causing the valve to be open. If the valve were closed the system would keep building pressure.


That's a horrible place to put it.
So you are back flowing the surge of air charge past the MAF in reverse!!!

Not only does the double meter the air you are then "loosing" but the meter is NOT designed to flow air in reverse. This can damage the meter which means very erratic or no air metering in the near future.


Your description and thinking of a bypass/blow off valve is completely wrong as is everything you have posted about it.

While some {IMO} improper supercharger setups also use a bypass valve to control maximum safe boost they are truly designed & used for surge control. It is for protecting the compressor from the reverse surge of air flow when the throttle plate closes and the pressure spikes & reverts.

Using it as a "safety" valve for engine protection is more understandable but any time you are using it for normal boost control you are just over tasking the compressor and adding more heat, compressor rpm, & lower efficiency. (i.e. why I state it's improperly used that way)

A turbo setup NEVER uses it for boost level control. That is the entire purpose of the wastegate.

2000 SVT #674 13.47 @ 102 - All Motor! It was not broke; Yet I fixed it anyway.