so i hear if u throw on a bigger crank pulley it will add more boost, is this true?

 

i will just change the revolution ratio between the crank and the supercharger, making it spin faster. You would be better off changing the supercharger pulley itself. My buddy has a supercharged jag, and he wanted to spen $400 on a crank pulley, when i told him the Smoothflow would machine him a pulley for less than $100.

 

yes you will get more boost because your are spinning the belt faster, but you will see less gains with a larger crank pulley than you will with a smaller supercharger pulley. Reason being the larger crank pulley doesnt just spin the supercharger faster, it spins everything faster, requiring more energy. So 1 PSI of boost from a smaller supercharger pulley might net 10HP, 1 PSI of boost from a larger crank pulley might only net 7HP because of all the other things it has to spin faster.

 

un, i think youd want a Smaller crank pulley, a bigger one would spin less.

 

No, it spins at the same speed, but the outer diameter is greater, making the belt travel further per rotation, which spins the blower pully more each rotation of the crank.

Overdrive crank pullies on these cars are very limited, as there is a large casting in the timing cover that doesn't allow the pulley to be more than maybe 5% larger.

As far as accessory drag, there isn't anything but the a/c and alternator on the belt. The alternator only puts as much resistance as it needs to maintain the power draw, and if you are racing you should have your a/c off anyway, it does shut off when you reach 98% or so throttle regardless. There isn't anything else to drag on the crank pulley, so the increase in parasitic loss is very small.

 

you are right, i couldnt grasp the concept, it took a min and a few drawings to realize you are right.