[tamathumper]

Just curious how much "dust" or "chuff" other people's SC belts are generating. I have had what I would estimate to be "low" tension on my SC belt since installation, and here are two pictures of the dust that builds up on the unit, after about 2,000 miles of operation.

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[ds968]

Wow, did not notice anything of the sort ( yet ) .

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[flash]

yeah - something is tearing up the belt more than it should. i would look closely at belt alignment, and to see that you used the correct lower idler pulley spacer (the one down by the alternator), and that your belt is in the center 6 grooves of the SC. then check to make sure the belt is not hitting the belt guard (adjust as necessary to clear)

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[tamathumper]

Belt is definitely in the center of the SC. I did check and re-check during installation that I had the proper spacer - because wouldn't you know it I put the wrong one in the first time and had to back that bolt out again. !#$@



I am definitely still hitting the upper belt guard, because the tension is so low. I keep taking it up a tiny bit at a time, and then a week later it's "tinging" again.

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[KRAG50]

I just did a two day DE, It was spotless before, I'll look tonight to see how much dust I see and let you know.

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[DaveN]

I definitely don't get that much dust. I get the odd bit of black rubber spittle scattered around the area after a week or 2.

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[KRAG50]

Checked mine last night, about 1400 miles on a new belt and two DE's, really no sitgn of much dust, in fact to only belt dust I could find in on the underside of the hood, and minor at that.

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[DaveN]

Yeah, I often have a little tiny black dust line there as well.

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[MB968]

Just some food for thought. Only a couple of reasons why you'd have to re-tension the belt that often:

- too low initial tension leading to wear which effectively lengthens the belt

- a bad belt that keeps stretching

- something moving in the geometry of the setup that is causing loss of belt tension

- belt wear from improper alignment of some of the members in the train

- an external member rubbing on the belt causing it to wear



On my s/c install on my Mazda/Probe, I initially had black dust as you show. It turned out to be inadequate tension. It took me a few tries to get to the right level. Once I found out how high I had to set it, the belt wear went away. I was surprised at how high it had to be/how much I had to stretch the belt to get it to function without slip. But ultimately that made sense. Under max. boost conditions, I could be pulling upwards of 40hp through the belt. More than from the normal accessory.

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[Lear35A]

[quote name='MB968' timestamp='1379441552' post='149490']

Just some food for thought. Only a couple of reasons why you'd have to re-tension the belt that often:

- too low initial tension leading to wear which effectively lengthens the belt

- a bad belt that keeps stretching

- something moving in the geometry of the setup that is causing loss of belt tension

- belt wear from improper alignment of some of the members in the train

- an external member rubbing on the belt causing it to wear



On my s/c install on my Mazda/Probe, I initially had black dust as you show. It turned out to be inadequate tension. It took me a few tries to get to the right level. Once I found out how high I had to set it, the belt wear went away. I was surprised at how high it had to be/how much I had to stretch the belt to get it to function without slip. But ultimately that made sense. Under max. boost conditions, I could be pulling upwards of 40hp through the belt. More than from the normal accessory.

[/quote]

But too high a tension will cause the idler pulleys on the SC to fail. This has happened to a number of us.

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[MB968]

I didn't have any idlers in my Mazda/Probe setup. And, since I designed the s/c system on my car, I was able to increase the tension while staying well below the capability of the installed bearings.



Just a thought on the idlers on your system. Many of the idlers that are widely available are not designed for more tension than is required to support xxx amount of torque/hp through the belt. This is due to the fact that a lot of the accessories do not pull that much HP. If the zone of enough belt tension to pull the hp while not overtaxing the idler is too narrow, it may pay to look at alternative idlers that are designed to support higher hp/torque and thus belt tension.

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[flash]

the idler pulley problem has currently only affected about 15% of the kits. not horrible, but not great either. the idler chosen has a large bearing, and should not be a problem, as long as it is not over-tensioned. it is designed to handle all of the load of a large V8 and its entire drive system. it's not that narrow of a window. the issue has been me failing to find a way to adequately describe how tight to adjust it, without also forcing people to go buy an expensive tool.

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[MB968]

I am not qualified to comment on how narrow the window is or isn't. My comments are for anyone who would like a bigger window of acceptable belt tension.



It's not really the size of the engine, or how much hp it makes. It is the amount of torque that the biggest draw accessory requires. For most engines this is the a/c compressor. The pulley on that by design is a fairly large diameter. Since torque is force times diameter, that keeps the force (belt tension) required to drive the a/c without slip low enough, only requiring normal belt tension. Most s/c's will require as much or more to drive than the a/c. But, typically their pulley size is small to get the rpms required. This leads to a situation not normally found on cars of any size or hp engine where a lot or torque is required for the size of the pulley. Increasing the number of grooves is a common way to help this as the amount of torque that the belt/pulley/tension combination can transmit is roughly proportional to the number of grooves, i.e. 8 grooves will transmit roughly twice what a 4 groove pulley will transmit. And, the same is true for the amount of wrap.



This could be another one of the things that others disagree with me on. But, for any of you engineers out there you'll find this basic info in your power transmission textbooks.

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[flash]

understood. as background, i conferred with arguably the most knowledgable guy in the country about this, who spends their entire day working on supercharger system design, as well as dayco themselves, before choosing this pulley. i was assured by both that the application was correct, assuming reasonable tension.



the belt is another story. because it is a double sided belt, it is softer in composition than other belts. this is to allow it to flex, because it is also twice as thick. this means that, like any soft material, any heat or abrasion will cause it to wear. high tension creates heat, and hence increases wear. once the belt has started to wear like that, it won't stop. the belt must then be replaced. this particular belt also does not like to be tensioned, slacked, and retensioned. each time it accelerates the wear. get it set. keep it set. if you have to remove it, it is best to replace it.

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[tamathumper]

Mine has, as previously stated, definitely been on the "low side" because I've been nervous about the idlers failing. I have every iteration of belt tension tool from the Krickit, the ArnnWorx, and the P9201, so if there's a spec I should be able to achieve it.

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[flash]

there is no spec as yet. i'm not planning to come up with one either, as i don't plan to use a tool, nor require anybody else to get one. i don't have the problem you seem to have. it's probably a "hands on" thing. it's just not that bloody hard to get it set right. the "window" is pretty wide. i don't really spend that much time tensioning the belt, and they all come out right.



remove the danged belt guard and watch the belt as you rev it. if it is dancing a lot, it needs more tension. if it is only dancing a bit, it's fine. there is over 200 degrees of wrap on the SC. it doesn't take that much tension to prevent slip. beyond that it only needs to be tight enough to sit still and not whack things.



at this point though, you may need a new belt.

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[TheDude]

Flash,



Perhaps a dumb question, where can I get such a belt? What make and model number?



Thanks.



MN

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[flash]

Gates DK060674



any decent parts store, amazon, yada yada

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[TheDude]

Thanks.



MN

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