8mm belt brakeage question

is there a relationship between size of top pulley and belt brakeage?
what I am asking should largest possible pully be use or is smallest pulley just as reliable

 

Do you run a roots or PSI? I run a 43 and it is about as small as you can go on a roots. I see tiny screw blower pulleys and the belts last numerous runs. (10-15)

 

Belt Breakage Cure

Rickey, The biggest secret to keeping a belt from breaking is to run it super tight, there are no other substitutions. People that buy the double and triple pulley systems out there are just wasting there money along with adding extra weight to there car. We have a top alcohol dragster and we used to break a belt every 1 to 3 runs for 6 years, it was the most frustrating problem we had. I spent $3,200.00 a year on 20 belts. I looked at a double idler system and just didn't want to spend $3,200 when some of the people that had the system were still having problems. Some racers told us we didn't want to tighten our belt to tight as it would take out the bearings on the blower snout. That is an absolute false statment. We decided to take a 14 inch chanel lock and pry together from the stationary handgrip to the end of the slider allmost as tight as we can get it after the motor is warmed up and have run it that way for almost 2 years and havn't broken a belt since. think about the force that is applied to the blower snout when you get on the throttle it is way more than than you will ever get on it tightening the belt to tight. I guarantee you this will fix a belt breaking problem. I have told several people that had the same problem I did and they have all thanked me and said they have had the same results. One person in chicago 2 years ago said he had never made a full pass down the track untill he did what we told him and his belt never broke the rest of the week end. I have told some of the people that sell belts to pass this info on to there customers but they do not as they would not sell very many belts if people did this. I can not tell you how many runs to put on a belt but we keep putting on more and more runs. I bought 10 belts 2 years ago and still have 5 new ones left out of the ten and am still running the original 5 belts. As they get a ton of runs on them we run the higher pass belts only in qualifying and the others in eliminations. I hope this is of some help to you or some of the other readers out there and if anyone has any questions just call or e-mail me. A lot of racers out there will not tell you how to fix a problem as they would rather you have problems at the track so they can beat you, but I am not that way. Racing is way to expensive, and I can not sit back and say nothing if I think I can help a person with a problem. Sorry for being so long winded. "Good Luck" Richard Putz phone 563-875-7528 or shirleyputz@yahoo.com

 

A year ago I went thru the problem of breaking 8mm belts every couple of passes on my roots blown car and it cost me a few races.
I even tried different idlers and tightening the belt like a banjo string and I kept breaking belts.... then this spring I switched over to 14mm belts and pulleys and ran the same belt all year long.

 

thanks for the info

PSI has told us that we needed to run 8mm as it was better for the blower

that is our reason to switch to 8mm

 

Rickey, I would agree with the 8mm set up if this is an easy to turn screw blower but not if its a big dual gear PSI roots.


I ran the 8mm belts with my 8-71 Kobelco and only broke 2 belts. When I switched to my 14-71 PSI I broke a bunch of belts and I tried a bunch of different things including RCDs "PS"/(problem solver) belts and nothing changed the outcome.
Then I spoke with a well known championship IHRA (PSI roots) funnycar crew chief and he told me to go to the 14mm set up and my problems ended.

Keep in mind that PSI makes and sells 8mm stuff