Just thinking, tell me why this could not work.

What if I take a D1 procharger that is safe to do some nice RPMS. And I pulley it to run 20 psi on a mostly stock TPI 350 camaro. The motor has forged pistons a mild cam and headers with 3.5" exhaust. Megasquirt and 42#'s with a 255 fuel pump are there too.

I don't actually want 20psi, 8 to 12 psi with intercooler is all I am looking for. But the idea is to control a BOV with a solenoid and my Megasquirt to bleed off boost pressure at whatever value I specify.

What I would get is a almost turbo like torque curve (full boost from 2000 to 5500 RPM) with the instant response of a supercharger. I could also adjust boost with my laptop without even touching a belt or pulley.

I say the D1 because it has the 4.44 step up ratio, and will make 20 psi boost with a relatively large pulley and has a safe 65,000 RPM limit that I won't touch even with a smallish pulley considering the TPI's low redline.

I know that even a slightly leaky BOV can kill a lot of boost on a turbo application, I am pretty sure I can make this work. But tell me what I missed.

 

Well, i dont know that much about compressors, but i hope you do not have stock connecting rods,all the BOVs i see are manually controlled with vacuum, i see superchargers making insane off the line boost without a loud blow off sound so i dont know what they do to them.

 

if i understand u right,u want to overdrive the supercharger so it gets into boost faster,but doing this will make to much boodt up in the higher rpms,u caould build an electronically controlled bov.(ive seen it done before ill try to find the link).but i doubt it would flow enough to bleed off enough presure fopr what ur wanting to do.any possiblity the a pop off type valve would

 

Sounds like it would work with a LARGE BOV, thats alot of CFM you are going to have to bleed off.

 

That is a bad idea.

It could work just fine on a displacement supercharger, like a ROOTS or a twin screw, but not on a centrifugal supercharger like the procharger.

Boost from a centrifugal supercharger is mainly a funkion of supercharger rpm, not the amount of air passing thru it. To lower boost you would have to release a huge amount of air, perhaps even more than the engine is using. You will also put the supercharger way off the the area in the compressor map where is it designed to work.

If you want to control (lower) boost on a centrifugal supercharger then you should add a restriction before the supercharger. Something like an extra throttle that is computer controlled.

 

Unloading the compressor wheel is a bad idea no matter how you do it, I’m debating if restricting it upstream is better for it then bypassing it, since restricting it upstream will essentially cause it to cavitate and unload unevenly (the reason that a vacuum sounds different when you block off it’s inlet). For that matter, an engine + supercharger is a much bigger pump then a vacuum, if you were going to make this thing variable then that would involve a very serious valve. Putting a set size restriction in the inlet to limit top end production might be the best solution, but that avoids allowing you to control the boost you see.