I threw my first belt 8 months after i put the ASP pulley on last week ,the 2nd came tonight. I know it cant be the ASP pulley or could it. What Idler would be doing the throwing. When the belt came off the first time it wasnt even under full throttle it was early in morning and i was at like 2k rpms. What gives

 

ive heard that with the asp pulley you need a katech tensioner. but i have the slp one so ive never had that happen to me

 

if youe tensioner is weak and you put an ASP pulley on it will throw the belt. you can either get a Katech tensioner (like i did), buy a smaller belt or a new stock tensioner.
Iwould try the smaller belt first since its the cheapest option. if it still throws the belt use that smaller belt and a new tensioner.

 

i threw a 770k4 and a 760k4. is it the tensioner top left or near alt and powersteering

 

Change out the tensioner - top left.

Another thing you can do is change out the wheel which runs on the top left tensioner. I used one off a stock supercharged 3800 V6 which has the same dimensions except the wheel has a ridge on one side which helps retain the belt.

 

Yes it could be the tensioner, but also check to make sure the ASP is still fully seated and it hasn't started to walk up the snout of the crank due to a loose bolt. This happened to me about 3 months ago.

 

I don't think it's your tensioner. I still have my stock one and have been running the ASP pulley for about 2 1/2 years. I threw my belt a couple of times right when I put on the pulley. Reason I found was b/c it wasn't seated all the way. Take it back off, re-install it and see if that cures your problem.

 

Try reinstalling it, sounds like its not seated good !

 

I've got 3 years on my ASP pulley never had a belt problem and i've spun mine to 6800 rpm a few times.
Hawk

 

Well i am getting the head and cam swap next month or so I really wanna try to hold off. It is weird it would start around 8 months after install..if it wasnt on properly it would of lost it at the time of install and dyno and the drive home and maybe weeks after but it didnt. hmmm

 

I started 'almost' tossing belts with my twin setup on decel after hard passes. The Katech tensioner solved my problem.

 

I had the same problem a few months ago. Started looking around to see what the problem was, and found that my crank pulley bolt had backed out so much that I could turn it with my fingers. If it's not the tensioner, and is the crank pulley bolt then use some red loc-tite on it and tighten it down to the factory specs.

 

X2 When your throwing belts 95% of the time it's b/c of a inproperly seated ASP pulley.

 

Good outcome was I gained 25HP for those remaining feet

 

Is that a scientific number?

Most of the time I've seen a belt throwing problem, a new tensioner solved it.

I suggest going for a Katech unit and forget about it.

 

I've had at least 3 local Fbody owners complain of throwing belts. Upon checking their setups we found their crank pulleys not fully seated and would throw the belt. A bad tensioner would do it also but i've only seen one bad one. It was on my 94 Taurus beater w 128K miles.

 

Well i might have a fix..i went to peep boys and got a pulley for a SC Regal the one that mounts too SC. then i compared it too the vette/firebird and it was an inch or so larger and has a better lip on it. the original one i took of didnt have much of anything ..thanks for the replys...So when you buy a ATI or ASP undrive get a SC pulley from a regal

 

Do a search on here. It's a VERY common problem with F-bodies