Blower pulley???

[siebersblack89SC]

I just bought a MARCH blower pulley and was wondering
how to tell what percentage it is.

Thanks.

[David Neibert]

Measure the outside diameter (top of ribs). I think a stock pulley for your car is 3.125. Divide 3.125 by the measurement you get for the answer.

If the pulley measured 3.000. (3.125/3.000)=1.0416666 or 4% smaller.

David

[curse]

the march pulley i got said it was a 10% when i first bought my car i was getting 9 psi of boost vac leak then i put the march pulley on got 12 psi

[Dave Neibert]

Correction, the stock pulley diameter for an 89-93 is 3.135 not 3.125.

David

[fastsc92]

i'd say if you have a choice.....go with an ESM pulley. They are aluminum....not steel and have a 5% and a 10% for $65. They are over 60% lighter than the stock pulley...and have a nice polished look. I got a 5% for mine, and i was getting about 11psi with the stock one. after...i went to the track and the gauge was past 15psi. I have a CAI, no cats...and a free flow exhaust...so it wasn't reading the wrong backpressure. Visit their site at http://www.embreemachine.com/. I was very very happy with them.