Dirt Cheap Supercharger
By Steven A. Richmond Sr.
OK, here it is. Please don't laugh until you've tried this, it really works. We've used these things for many different jobs where we needed a lot of volume at low- to moderate pressure levels, and they almost always work out very well.
All you need is a "smog pump"! I assume everyone knows what I am referring to. In the USA, at least, almost every new car has been required to have one of these since around 1970, (by government regulations) to pump air into the exhaust manifolds, which supposedly facilitates more efficient conversion of the unburned hydrocarbons as the mixture passes through the catalytic converter.
If we build them into a machine, we by them new, but there are piles of them in junk yards which you can actually
get for as little as $5.00 each. People don't realize just how efficient these little pumps are. At 8,000 rpm you can feel a strong air blast from a one inch pipe attached to one of these standing over twenty five feet away, they will actually produce up to sixty pounds or more (for a VERY short time), and if you block the air flow completely the pump will stop a five horsepower electric motor.
Most of them take in air though an impeller right behind the drive pulley, which is fine for most purposes, but some are equipped with a separate inlet port complete with a small air filtering device,- which can prove useful in certain circumstances.
You can even hook these things up "back to back", and the first one will drive the second,- with amazing efficiency. If you get the kind equipped with both inlet and outlet ports, you can the make a closed loop and either one will drive the other,- in either direction. There's a novel way to transmit power! If you do try this, be sure to include an intercooler in the plumbing,- the only thing I've found that will ruin these pumps, is heat!
Some of the pumps I'm describing have more capacity than others. I like to play with the ones from 350 cid Chevrolet police cars, or 454 cid trucks. It takes four to six of these to provide ample boost for the average V8, but one or two should suffice for most motorcycle engines. I built a setup using these on a small V8 once, and used a automotive air conditioner pump, electric clutch & pulley, so that it was not necessary to wast fuel driving the arrangement until it was needed.
90% of the pump body is aluminum, so they are relatively light, and it's not difficult to polish them up and radically alter their appearance. By the time you've done that, and added a aluminum timing pulley,- no one will ever guess what it is/was, or how little you have invested.
Be careful how much intake pressure you apply to a high compression engine. You probably shoudn't try to go over 8 - 10 pounds on any engine with a 9 :1 compression ratio or higher. We attached one of these to a friend's son's go-cart engine (Briggs & Stratton) and the power increase was very impressive,-- the kid decided he'd like even more power, and changed to a larger primary pulley. I'm not sure if it was the extra compression or detonation, but it didn't run very long after that before the complete cylinder assembly separated and exploded off the engine block (no kidding!),-- kind of reminded me of pictures I've seen of Blown(up) top fuel drag engines.
If anyone is not familiar with these types of pumps, or has any trouble understanding how they can be attached,- driven, etc..., let me know, and I'll post a photograph of one mounted on a prototyping test setup.
Steven A. Richmond Sr