Need explanation about pulley for whipple supercharger

[zachman]

I called Whipple today and asked what size pulley would I need to run to make approx. 12lbs. of boost on my 2.3 whipple. They said 2.75 with a 4 lb. lower pulley to prevent belt wrap. What and where is the 4lb. lower pulley located?

 

[wazslow]

I called Whipple today and asked what size pulley would I need to run to make approx. 12lbs. of boost on my 2.3 whipple. They said 2.75 with a 4 lb. lower pulley to prevent belt wrap. What and where is the 4lb. lower pulley located?

Its the crank pulley.

 

[r.barn]

You make the crank pulley bigger and blower pulley smaller, like on a bicycle. Otherwise the blower pulley would keep getting so small it would look like an alternator pulley on there and have all kinds of belt slip issues.

 

[BruceH]

I called Whipple today and asked what size pulley would I need to run to make approx. 12lbs. of boost on my 2.3 whipple. They said 2.75 with a 4 lb. lower pulley to prevent belt wrap. What and where is the 4lb. lower pulley located?

Sounds like they were talking about a cobra or lightning.

 

[stkjock]

Sounds like they were talking about a cobra or lightning.

/\ agreed

It's a 10% overdrive crank pulley by Innovators West

 

[rayS197]

Sounds like they were talking about a cobra or lightning.

/\ agreed

It's a 10% overdrive crank pulley by Innovators West

Agreed. the 3.125 should put you there depending on what Gen you have. Gen 1 would be the 3.125, Gen 2 with that size might be a little more than 12 psi

 

[zachman]

Will adding the 10% overdrive pulley shorten the the life of the alternator?
I have been told an overdrive pulley makes the alternator spin faster and shortens its life. Don't know if that is true.

 

[stkjock]

to some degree it likely would