: Upper pulley and Belt Slip



Blackdevil77
04-16-11, 12:49 PM
I've heard many people talk about belt slip when going with a smaller super charger pulley, and I've also heard of a lot of people say they never had a problem with belt slip with the smaller upper pulley. I just have a few question. What size is the stock upper pulley and what sizes does the aftermarket offer? I have only seen one size for the upper pulley available and that was the 2.6 inch (I believe, might be 2.55). Also, The LSA has 8 rib pulleys and belts. I was wondering if it is possible to use the LS9's 11 rib pulleys on the LSA to reduce the chances of belt slip. Would doing that help to decrease the chances of belt slip, if it is possible to do? And how much would it coast to run all 11 rib pulleys with 11 rib belt?

Ross L
04-16-11, 03:50 PM
Belt slip is usually talked about by those who *don't have* the upper pulley as a reason to run the lower pulley. I've never read about, or talked to, anyone experiencing slip with the upper. Mine was pressed on, looks stock, never slips. Don't know about 11 rib belt. Good luck!
Ross

newcadman
04-16-11, 06:45 PM
Belt slip is usually talked about by those who *don't have* the upper pulley as a reason to run the lower pulley. I've never read about, or talked to, anyone experiencing slip with the upper. Mine was pressed on, looks stock, never slips. Don't know about 11 rib belt. Good luck!
Ross



Ross-- with your upper pulley looking "stock" would be curious to know which vendor you bought from and who pressed it on ?

Ross L
04-16-11, 07:42 PM
W4m pulley. Friend helped w pressing it on. It's black, no pin

newcadman
04-16-11, 08:01 PM
W4m pulley. Friend helped w pressing it on. It's black, no pin


Thanks. Good info to know.

Domsz06
04-16-11, 11:33 PM
I've heard many people talk about belt slip when going with a smaller super charger pulley, and I've also heard of a lot of people say they never had a problem with belt slip with the smaller upper pulley. I just have a few question. What size is the stock upper pulley and what sizes does the aftermarket offer? I have only seen one size for the upper pulley available and that was the 2.6 inch (I believe, might be 2.55). Also, The LSA has 8 rib pulleys and belts. I was wondering if it is possible to use the LS9's 11 rib pulleys on the LSA to reduce the chances of belt slip. Would doing that help to decrease the chances of belt slip, if it is possible to do? And how much would it coast to run all 11 rib pulleys with 11 rib belt?

the big issue with the upper really doesn't apply to our s/c's. With the v1 the maggie lots of people would put a smaller pulley and have lots of slippage. the big issue with the stock one is a few thinks.

1) you can't put it on or take it off with out removing the snout and having it pressed on or off
2) if the shop pressing does it wrong you have to get a whole new snout
3) most of the uppers do not look stock so it's a dead give away to the gm dealership your not stock (void warranty)
4) if you do go to a higher hp in the end, you are more likely to slip....

to convert all the other pulleys to 11 rib you might as well just put the lower one on. Once you pull your stock lower pulley off and put the new dampener and pulley you can change pulleys in about 15 min. It takes me all of about 4 hrs to go from stock to a 9.5, so IMO i'd rather do the work myself and use the lower. There will never be any slip with a bigger lower.

good luck with what ever you do, there are lots of happy members running smaller uppers and larger lowers. Just have to decide what you want.

shade
04-16-11, 11:59 PM
Dom has good points -
1 point to make with the upper is you can run a larger idler pulley which will also keep belt slip at bay. Using a larger idler as well will prevent belt slip when you go into higher horsepower applications.
I have a 255 no issues and I did opt to get a larger idler pulley

PremierJosh
04-17-11, 12:24 PM
I had zero problems with my 2.55 upper. Now I have added a 8.6 lower along with
it. I had the wrong belt on it originally and had slip now no problem at all. 16psi and smiles.