Can someone backup my math
Turbo Mini Forums

Trying to work out the ratio needed for the eaton supercharger on my friends 998. Spec below, boost pressure required will be 10psi at the carb. I've done the calcs myself, and had a friend back them up but we have differing results, concidering the difficulty in changing the ratio i dont want to get it wrong.

Spec,

1042cc
Morspeed ph2 cam (0-6500rpm)
940 head
m45 charger
rs type intercooler into a blowthrough metro turbo setup

Could someone who knows the calcs well run them through and let me know the ratio of crank to charger and what pressure drops you assume for the system (accross intercooler).

Edited by andeh on 5th Nov, 2006.

I've seen the future and tbh its Pie

Hi there

Ive got a supercharger calculator in the turbo section here -

http://uk.briefcase.yahoo.com/twin_charged

I think its pretty self explanatry, you will need the bore and stroke of the engine, its currently set up for an eaton M45. Just change what you need to in the blue boxes.

Cheers

J

Edited by blown_imp on 5th Nov, 2006.

I came up with spinning it at 0.87 times engine speed

J

I used an m45 on a 1310 mini using the mpi pulley which is 12 cm diam , don't remind the charger pulley diam, but it gave us 7 psi so it should give you 1310/1042*7=8.9 psi
fab

The calculator says - the crank pulley would have also been about 12cm!

J