|I once found an interesting article about
supercharging on a budget. Then I lost the article and it
took me ages to find it again. Now that I've found it I'm not
going to let it go!
"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
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
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 set-up
using these on a small V8 once, and used a automotive air
conditioner pump, electric clutch & pulley, so that it was
not necessary to waste fuel driving the arrangement until it
90% of the pump body is aluminium,
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 aluminium 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 shouldn'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 set-up."
This article was written by Steven