Belt Slip on H.O. Alternator w/overdrive pulley

[TazMan]

Hey everyone. I bought a 200 Amp alternator not too long ago for my 03 Grand Am GT and because of the different power curve on this alternator I have to use an overdrive pulley to get it to charge at idle. The problem is, I guess because the pulley is smaller, the belt doesn't seem to get enough bite on it and it squeals alot. I tried using a belt a 1/2" shorter, but it was too short. I tried shimming the alternator up as much as possible before the belt would rub, but it didn't help much. The tensioner and the belts were new. The belts I'm using are Goodyear Gator belts. If I go back to the slightly bigger pulley, the belt stops squealing, but it doesn't charge at Idle. Does anybody have any suggestions as to how I can get this pulley to grab better? Thanks

[RedBird]

how's your tensioner? might have lost some of it's tensioning ability if it's older....

[TazMan]

how's your tensioner? might have lost some of it's tensioning ability if it's older....

I replaced the tensioner and the belt with a gator belt when I put in the new pulley.

[geoffinbc]

How many degrees of wrap do you have on the pulley?

[TazMan]

How many degrees of wrap do you have on the pulley?

I can definitely tell by eye that the belt wraps around alot more of the bigger pulley then it does the smaller one but I can't get an exact measurement because the bigger pulley's on there right now. I was trying to think of a way to get more wrap on that pulley but couldn't figure anything out.

[geoffinbc]

The only way your going to increase wrap is to add an idler to change the angle. But that is not always easy. More tension is always an option but that puts strain on everything in the system. What about a larger crank pulley? It would suck up a bit of power because everything would be driven faster unless you get different pulleys for everything but the alternator. Then you could go back to the stock alt pulley.

[TazMan]

The only way your going to increase wrap is to add an idler to change the angle. But that is not always easy. More tension is always an option but that puts strain on everything in the system. What about a larger crank pulley? It would suck up a bit of power because everything would be driven faster unless you get different pulleys for everything but the alternator. Then you could go back to the stock alt pulley.

If I could move the idler pulley over that would definitely give me more wrap, but I don't see any way of doing so. I tried adding more tension by shimming up the alternator but it didn't help much. The belt was really tight too when I did this. I had thought about a larger crank pulley but was concerned about the loss in power. I can feel a slight difference in power just from changing the alternator pulley. It's not much, but I figured if I was overdriving all the pulleys, then I'd lose alot more. I thought about changing all the pulleys but the alternator, but I was really hoping to avoid all that. Any idea where I would get custom pulleys like that and how I would figure out how much smaller I'd have to make the other pulleys?

[RedBird]

Hmm.... how big is the pulley on your tensioner? and is there any way you can get a bigger one on it? might give you more wrap and a bit more tension at the same time.......

[TazMan]

Hmm.... how big is the pulley on your tensioner? and is there any way you can get a bigger one on it? might give you more wrap and a bit more tension at the same time.......

Where the tensioner is, if I put a bigger pulley on it, it would actually give it less wrap. A bigger idler pulley would probably give me a little more, but its very close to the top of the tensioner so i can only make it a little bigger.

[RedBird]

hmm. maybe smaller tensioner pulley and bigger idler?

[PCGUY112887]

Idle at a higher RPM? Do you have any kind of tuning capability?