I've read combos that members have that state they are using a 1/2/3# upper pulley in conjunction with a lower pulley 2/4/6#ers. My question is since the upper pulleys are rated to give its advertised boost with the stock lower pulley, how much more boost do they produce when the larger lower pulleys are used? I would think that a 2# upper would yield closer to 3#s when used with a 4# lower and probably 3plus #'s when used with a 6#er. Anyone got any data on this?

 

This will help.

 

Most claim the pulleys won't give you the amount of boost they sell them as. I don't know if I agree or not. "But" I happen to have a 2lb upper 2.80 "and" a 4lb Lower 8.50. On the upper the MFG has shown many L with 3lb increases. As far as boost, I have plenty, probaly 15-17 at WOT, but more noticable is the instant 10 lbs I have at like 1/4 throttle, as I get into it, it climbs instantly off the scale way past 10, and then continues to climb all the way into the tach area of the dash board. Got to get a picture of that one day

Lower Pulley Sizes

2# ~ 7.90"
3# ~ 8.17"
4# ~ 8.50"
5# ~ 8.75"
6# ~ 9.00"


Upper Pulley Sizes

Stock ~ 2.93
2# ~ 2.80

I have a spread sheet on the hp gains and torque, but it won't show right here. We showed it once somehow, if I can find the old post.

 

it won't work

 

Ok now I have some data to crunch. I didn't see any formula's that took the circumference of the pulleys into account. That is the tell tale dimension. I'll crunch the numbers and get back to you guys. Maybe I overlooked something as it is 4am. Later and thanks.

 

The diameters that are posted are correct. They are measured where the belt rides not the the actual outside diameter of the pulley. There is at least .250 lip on most pulleys...

 

AHHHH Wendy...Imagine our Garage if we were married..LOL

 

Is your combo for a quick change at the track? How do you like the setup? Slippage?

 

If you have Excell installed you will see the spreadsheet that does blower RPM here

http://www.svtlightnings.com/svt/how-to/blowerrpm.htm

If not you can dload the spreadsheet and open it in your application...

Doug

 

Thanks Doug for the link

AND

Thanks Andy for the foot work

 

LOL. Thats pretty good!!! It would be the envy of many thats fer sure.