Since the blower is parasitic on the engine no matter if you're under boost or not, can a switch be added that would switch a pulley between freewheeling and engaged? That way, we can get efficiency with a freewheeling pulley and then get the power when we want it with a flick of a switch to engage the pulley.

 

I think you have been watching "Mad Max" a few too many times... heh


Theoretically you could have a clutch style pulley, similiar to that used on an air conditioner. Only issue I see with that is the relative small size of the blower pulley, as well as the fact that you would be disengaging the water pump, driven by blower rotors. Also, stopping the blower would make it very difficult to draw air through the blower into the intake. You would need to rig a bypass system connected to the blower clutch switch.

 

This is unnecessary. The SC by-pass valve completely unloads the SC under hi-vacuum / cruising conditions, eliminating most of the parasitic losses associated with a SC producing boost when none is needed. I seem to recall reading on the Magnuson site that it uses 1/2 HP when unloaded.

See SCBPV theory thread here.

Edited --------

Link to Magnuson claim of 1/3 HP loss for M90 SC here.

 

That's awesome.

Forgot about the water pump...certainly don't want to shut that thing off.

And yes, too many Mad Max movies for me. Oh, don't forget Lone Wolf McQuade or My Science Project for examples of switch activated Blowers...

 

OK, how about this. Instead of the pulley being the "on/off" device, how about one at the by-bass valve being electronically actuated instead of by vacuum? That way I can cruise around only loosing 1/2 HP in by-pass mode, and then when I need to have fun I can switch it on. Anyone think this might work well?