996r916sps

Does anyone know the formula for calculating boost? I think I've heard of one that you must know pulley sizes (crank&blower) and rpm.

Thanks!

996r916sps

Use the formula:

((14.7+Boost) / 14.7) x (engine liters / 2)) / Supercharger Size liters = Theoretical Pully Ratio*

*Assuming "0" inlet losses and 6.5" crank pulley.

For 6 psi boost with a 1.5L supercharger on a 5.0 engine: ((14.7-6) / 14.7) x (5.0/2))/ 1.5= 2.34 ratio

Then divide the pulley ratio(2.34) into the crankshaft pulley size (6.5") to determine supercharger pulley size (2.77").

6.5/2.34 =2.77" supercharger pulley size. Note: We stock pulleys in 1/8" or 1/4" incriments from 2"-4-1/8". Typically, 1/8" in size equals 1 psi boost.