so i was running a 4060395 gatorback on my 4.25" pulley (7psi on AP1). outta nowhere, my belt snapped and disappeared from my engine bay somewhere on the road. i'm getting a bunch of stuff done to my car right now and i gave my mechanic the 39.5" belt to put on there. he said he wants to put a 40" belt on there because he thinks that because he has to put so much force on it to get it on the pulley, it is putting too much stress on the bearings in both the crank and the supercharger. he says i should use a 40" belt and set the tension higher on the SC tensioner. opinions?

 

What are you asking? Is it okay to use a 40" belt...?

Was that gator belt new? If so, it sounds like it was TOO DAMN TIGHT, especially if it snapped. 20 lbs of force is all Comptech requires, and that isn't all that much.

I had a gatorback belt, and I thought it was a total POS! In between the ridges on the underside of the belt cracked so quickley because the area is so thin.

I purchased a regular ribbed belt, and have had much better luck- I can't remember the size though.

 

the gatorback was new. i checked for proper tension, too. i' basically asking if it's ok to use a 40" belt instead of a 39.5" (as recommended by Sideways' sticky at the top of the FI forum). my mechanic urged me to use a 40" belt instead and just adjust the tensioner a bit more, because he said with how hard it was to try to get the 39.5" on there, it is probably putting undue stress on the bearings in the crankshaft and in the supercharger.

 

Thats BS.

If it doesn't fit, then unbolt the SC and put the belt on then bolt the SC back up.

 

he refuses to put the belt on for me if it's the 39.5" lol
i guess he doesn't want to be the one responsible if his theory is right. but wouldn't it be ok to use a 40" if i just set the tensioner accordingly?

 

Go with the larger belt. That thread can be updated it the information is wrong.

 

sweet, thanks for the reply. i guess he might have been right!

 

I used a larger belt for my SC. That's why we have a tensioner in the first place...to take up slack. If it won't fit then it won't fit...

 

i could have sworn you were local to the DC Metro area last year...

 

he was sucker moved to the other side of the country