Two BOV's
Some of this you probably already know, but if not.
Not enough BOV stalls the compressor and creates a noticeable shudder. The shudder is the compression reversing direction and coming back out the inlet. Just like and airplane wing, if you demand too high of a lift (ie. too high of a discharge pressure) it stalls and can no longer create lift/pressure. In an airplane you fall out of the sky. In a compressor, the pressure reverses directions and comes back out the inlet. In a split second the discharge pressure falls, you get back to a low enough pressure that the compressor can push and and compression resumes. This happens many times per second and creates a noticeable shudder. It also load/unloads the belt rapidly.
So, with all that being said some of the signs you are out of BOV: If you hear a shudder, are throwing belts when you get off the throttle (and everything is aligned), or you are pushing off your inlet. A cog or gear arrangement is less tolerant to inadequate BOV than a serpentine.
A split second of stall and one moment of intake reversion is normal for most S/C setups (which is why people blow off those velocity stacks at the track), but it shouldn't be a long enough event to cause a shudder, break a belt, or blow off a full inlet.
Every car is different, but most I don't think would NEED a 2nd race valve until probably F2-ish range. At that point I think I would just go up to the prorace valve - but it is a pain in the *** to fit.
Not enough BOV stalls the compressor and creates a noticeable shudder. The shudder is the compression reversing direction and coming back out the inlet. Just like and airplane wing, if you demand too high of a lift (ie. too high of a discharge pressure) it stalls and can no longer create lift/pressure. In an airplane you fall out of the sky. In a compressor, the pressure reverses directions and comes back out the inlet. In a split second the discharge pressure falls, you get back to a low enough pressure that the compressor can push and and compression resumes. This happens many times per second and creates a noticeable shudder. It also load/unloads the belt rapidly.
So, with all that being said some of the signs you are out of BOV: If you hear a shudder, are throwing belts when you get off the throttle (and everything is aligned), or you are pushing off your inlet. A cog or gear arrangement is less tolerant to inadequate BOV than a serpentine.
A split second of stall and one moment of intake reversion is normal for most S/C setups (which is why people blow off those velocity stacks at the track), but it shouldn't be a long enough event to cause a shudder, break a belt, or blow off a full inlet.
Every car is different, but most I don't think would NEED a 2nd race valve until probably F2-ish range. At that point I think I would just go up to the prorace valve - but it is a pain in the *** to fit.
