Thread: 8 rib conversion with stock crank pulley

Basically am wondering if this can be done and done safely without the belt slipping at high rpm's. At the moment, I have the oversized 3.5" Tensioner pulley with stock 663 belt with a 3.4 pulley. It doesn't seem to slip at all and doesn't have an on again off again squeal like I had with the stock tensioner and 658 belt, but I really like the way an 8 ribbed belt looks and it seems it would have the most pull on the supercharger pulley since it's 8 ribbed anyway. If I can't or not recommended to go for the 8 ribbed conversion, what's the largest pulley I can run with the stock belt and oversized tensioner? Trying to combat some knock issues. Thanks for the input.

Get a regular tensioner pulley to make up the size difference of a larger pulley?

The crank pulley is only 6 rib so how are you going to run an 8 rib belt on a 6 rib drive pulley. You can run a 6 rib all day long but an 8 rib conversion, it is not.

Jeff

Just so you guy's don't think I'm idiotic for asking, I did do some research before asking about this. I read this and post and it got me thinking. http://www.grandprixforums.net/threa...et-a-belt-wrap I just wanted to hear some more opinions.

you can do it. the belt gets f'd up at the valley between the 6th and 7th ribs....

but to fix that all you have to do is jack up the car, remove the sc belt. start engine and hit outer shoulder of balancer with 4 1/2" grinder at about a 70* angle for a second or two and it will allow the belt to ride all the way down and keep you from separating the 8 rib belt into a 6 & 2 rib.

i havent done it in forever, the SFI balancer is far nicer and safer

Ahh I see. Well in that case I would probably just save up for the 8 rib balancer or put my money towards something else.

Refer to my email but... Ive been doing this for a while with no issues. I may eventually put the OD on but then again maybe not...

Unless you are going sub 3" pulley then you shouldn't ever need an 8 rib setup. The more free flowing your exhaust the less stress there is on the blower, that is why people see a drop in boost with when they have better exhaust. They aren't seeing a drop in power the are seeing the engine working more efficiently and making more power. Boost is nothing more than a measure of back pressure in the manifold. The more air you can put through the engine the more power you can make.

Jeff

I don't get it ? Why are we using an 8 rib belt on a stock 6 rib crank?

I think he was a little confused.

Jeff