whipple belt

does anyone use a 8mm belt on a a980 whipple or is ita PSI only thing.

 

Belt

I'd Use Whatever Pullies You May Already Have
8,14, Or 13.9 Would Work Fine

 

I've used 8mm with a whipple. Allows you to change overdrive in smaller increments.

 

we plan to run 55-60% od,how much did you have?how many runs/belt?

 

Belt

I Ran 55 Over Most Times, On A 14 Mm Belt Ran For Like 3 Years On One Belt. Never Broke One.they Real Easy On Belts

 

Most belt failures are from detonation.
When a competitor breaks a belt its awfully easy to beat them. I geuss thats where the saying "You must first finish the run in order to win".

I run 65mm wide belts (narrow) and put about 60-90 runs on before changing them, while staying competitive on the track. But I have my detonation minimized.

 

what are things you can do to prevent detonation

 

thank's for all the answers.here comes another one :woudn´t it be better to run the belt on the other side of the idler pulley? looked at some old dragster pics from the 60´s and everyone seemed to run the belt that way.you get a little more area or teeth in "grip".

 

Bill
The biggest thing that causes detonation on blown alky motors is too lean of an air/fuel mixture. The trick is to have a good A/F ratio throughout the RPM band. For instance, we've had motors in the past where we would detonate hard enough at 4500 RPM where we would knock the porcelain out of the spark plug, but at 7000 was filthy rich. The bearings and head gaskets wouldn't last and we thought this is because we're making sooooo much power. Later we adjusted our fuel curve, made more power and parts last much much longer.
Ignition timing is another.
Sharp edges in the combustion chamber(sand roll these away).
Hot air won't help but run as much alky thru the blower as possible while keeping your port nozzles small for the purpose of keeping distribution even.
ta455
Think about when the idler pulley is touching the inside of the belt (the teeth). When the motor has a load and the RPM are up the blower will be pulling hard. At this time, the belt is stretching on the tight side and barely even touching on the idler.
Now imagine if the idler were on the other side, the belt is trying to fly out but its forced back by the idler. This is hard on the belt.
Many also run the belt too tight. Check the tension after everything is warm, especially when running aluminum block.
This is what I've learned and it works well for me.

 

Whipple

If You Run A Regular 13.9 Or 14 Mm You Will Not Need To Switch The Idler, Its Not Going To Jump Teeth, I Even Ran A Mismatched Combo 13.9 And 14 Pullies And Never Had An Issue
I Was Wondering Why Some Run A 65 Width Instead Of 75 Width?
The 75 Would Have To Be Stronger Right???

 

Yes the 75 mm wide are stronger. I believe the 65 wide was the "original" and thats just what everyone got started using.

14mm on a 13.9 pulley,, hmmmm. Actually I'm contemplating trying a few things on the dyno and it forced me to use a 14mm belt for length availability reasons. But I didn't want to buy pulleys.

Are their people out their running 14mm belts on 13.9mm pulleys while in competition?

John Knox of Sassy Racing Engines told me this once but...

 

Belt

I Wouldnt Try It On A Roots... The Whipple Didnt Care Though. It Was A 65 Mm Width Also, 55- Over And 9,000 Rpms