[johnmyster]

Check valves on a normal car are there because the engine isn't ALWAYS a vacuum source. Thus, that big vacuum resivoir can store up enough vacuum for one or two pulses even when you're drag racing. Not to mention, it keeps vacuum stored for use by climate control, egr, purge canister, and cruise control operations on applicable vehicles.

I don't think a check valve will help you unless you plan on cycling your pump.

If you hook your fishtank pump up to your vacuum gauge directly, how much does it measure? IE., if we take the leaky pump out of the equation?

20 inches of vacuum is only about -10psi. If Schultz manages to backpressure a booster, I'm sure he can figure out how to have +10 psi on it in a jiffy...

Perhaps a pump from a vehicle that had air brakes could be belt driven by your motor shaft and give you some help. Or perhaps you could run an a/c compressor instead and activate the clutch with your brakelights. Thus, you'd have regenerative braking braking assist! Whoa, think about that three times fast!

(A/C compressors count on oil in the system, so they wouldn't last forever without it. However, pick a common model like an GM R-4 or A-6 and you can find them all over the place.)