Stillen supercharger belt slipage
 

I've been trying to figure this problem slowly out for a few months now... my belt slips at high rpm. I tried different belts (same length) then tried the extra pulley for grip with the longer belt. Same thing.

I sprayed CRC, didn't help even though I could tell belt became sticky.

I replaced my belt tensioner with a new one, no difference.

I feel like I am out of options.

I am running stock pulley sizes, stock impeller that came from stillen. Nothing modified there.


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Check out Topgunz Air-to-Air thread, there is a lot of discussion on belt slip and some pretty good solutions.

Should I add also that both belt tensioners show that each belt I tried is too loose.


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I did. I followed all of them I think. Thanks though


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Have you tried the "high traction" pulleys from Vortech?

I'm using the "high traction" pulleys on the SC and the serp side but not the jackshaft pulley, but using a larger jackshaft idler pulley (due to smaller 3.0" SC pulley). I'm also using the extra idler pulley for more wrap on the serp side. I don't believe I'm getting any slippage. :driving:

Also I've read that CRC will make things worse in the end.

I have not tried those pulleys. I'll consider it.

Do you know if it's possible to adjust the tension of the short belt on the supercharger side without taking the whole supercharger out? I have a hard time seeing wrench size needed because it's kind of tight there


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Gates has new green series belts out now. Supposeded to be really good.

Yes from underneath. Two long 3/8 extensions, a wobble and a 14mm shallow socket. The bolt on the idler itself should be a 19mm wrench. Back it off just a little and then go beneath and increase the tension a little. Tighten the pulley back up.

Keep an eye on the pulley as the adjuster setup puts all the tension on the inside and the pulley can ride askew, potentially causing belt to ride off the rib or put lateral pressure on the bearings. I used a larger, thicker washer behind that 19mm nut so it will sit true when tightened back up.

Don't try and tighten the tensioner from below too much at once. It is really easy to over tighten. Better doing it a couple times instead of getting aggressive with it from the start.

There is a possibility the main bracket itself is flexing under load which will cause slack on the sc belt and slip. However, with the light load setup you have on there it is more unlikely to happen. Unless for some reason you have a bracket that has been weakened somehow.

The price that guy is charging for those brackets is rediculous. I had mine made for $100 and it is way better than that.

Stillen supercharger belt slipage
 

I put on another Gates brand new belt and this one even though "same size" even comparing outside of the engine was a tad bit shorter. The belt tensioner shows the belt properly tensioned now. BUT I still get belt slip just as bad.

And when I compared by hand, the tension on that belt to the SC side belt. The SC side belt was looser. I will tighten that and if it doesn't work, I might take off the supercharger cause I'm done dealing with this hahaha

Topgunz- Yeah, I have the lowest power setup on the stillen. I shouldn't be getting any movement.

And I agree that bracket is way too expensive.


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You can also access it from above with a crow's foot and a ~8" extension. Which way to turn it, gets confusing since it's all upside down, but just keep track of the turns and see if you're going in the right direction. It sounds silly, but it's easy to lose track of it all when you have to keep removing and re-seating the wrench every 1/3 turn. It's clunky, but you only have to do it once.

I'm curious about why you think the belt is slipping. Low boost? Rubber dust coming off the belt? Noise? What are the symptoms?

I found out that I had a belt slip issue by using a IR heat detector and measuring the SC pulleys. They should all be about the same temperature unless they are slipping and then you will see a higher temperature.

IR heat guns are around $25 and are quite handy to have around when chasing any heat problem. https://www.amazon.com/Etekcity-Lase...rmometer&psc=1

Some things I've learned about industrial belt-drive systems over the years. Should apply to SC drives. Hopefully, it will help. Maybe not.

The belt itself is seldom the problem. (Assuming what you are using is reasonably close to original specs and it's not worn out.)

Pulley material/construction is just as important as with the belt. If the pulley doesn't provide some grip for the belt, you're going to have slippage. Get a belt/pulley combo with sufficient stiction and you can get a little sloppy in other areas.

Everything else being the same, pulley contact area will have the greatest effect. Contact area can be increased by having the belt wrap around more of the pulley. Contact area will be decreased if the belt doesn't run flat on the pulley.

Flexing of brackets and other mounting hardware should be kept to a minimum. Flexing causes loss of tension and misalignment of the belt and pulley. This was the cause of many problems I ran into.

Belts will naturally vibrate but if they start to flop, you need more tension or an idler.

Tension is important, but y'all already knew that. :)

I get a loud belt squeal along with loss in boost exactly when the squeal happens. Only at high rpm.

Also, my belt tensioner reads that every single one of the 3 brand new belts I tried is not tight enough.

I tightened the SC side little belt and it didn't help.


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You may need my added idler pulley kit. It gives a lot of wrap around the jackshaft pulley.