MicroSquirt.com read only forum (Jan.15,2018)

I'm considering putting together a supercharged motor, and i'm rather curious as to if/how i can calculate how much boost a given pulley size will make.

For instance, it would be a 1998cc four banger, with an eaton M90(yeah, too big, i know) on it.
The engine sucks in about a liter (61ci) per single rotation, while the blower puts out 90ci per rotation.

In theory, if i had the blower drive at 1:1, would that give me 7psi of boost? (50% more air then the normal 61ci)
Or am i way off base?

Looking around online i've only found rough HP calculators based on pre boost output and given boost levels, nothing to actually calculate how much boost a setup would run.

Your pretty close to the applied therory but the truth is it doesn't usually get you very close. I am putting together about the same combo and I am quite sure it will not obtain that amount of boost. I have conversed with others who are supercharging and the math just doesn't come out. Usually on the low side.

For your setup I would expect about 4psi. The good news is you have plenty of headroom with that large of a huffer to make it interesting witout building the heat the little ones do. But, the faster you turn a super charger the faster the boost will come on at lower rpm's due to the fact they are not very efficiant at lower speeds.

I would strongly suggest you start your project by buying Corky Bells "Supercharged" book and start reading. It is a wealth of info and formulas.

Todd

Interesting, i'll check that book out, thanks

Second that! "Supercharged!" has all the equations you need for computing pulley sizes, estimated hp, etc. etc. Very easy read, and when you're done, you actually have a pretty good clue.

I've read a few other books, and none of them are nearly as useful as Corky Bell's book.

- Karl