my84-944

I just broke mine so if cost=value than I am so in it is silly!
Keeping in mind that they will need to show significent improvement over the standard belts if there is a price increase.

spedracer18

id be in for a few. Im a biomaterials emphasis (Biomed major) and we have studied the differences between natural polymers (natural rubber) and synthetic polymers (Teflon) extensively. The synthetic teflon will have a greater tensile strength and less of a tendency to break down. The properties such as elasticity and brittleness would change depending upon the machining procedure. But in the long haul Teflon will be stronger, and more durable. Teflon also has a smaller average MW than that of a normal rubber but it follows a normal distribution rather than rubber having a distinct molecular weight. This is all assuming that the Conti belts are made of natural rubber. I guess i dont really know though...

SD Porsche Fan

I would be willing to pay more for proven reliability. As our cars age it only seems natural to upgrade to more current technology if it can improve longevity and reliability.

my84-944

YAH What he said.....

Mike C.

Where would the data come from regarding proper belt tensioning? I don't think I'd be willing to experiment with that. Maybe it would be more tolerant to over tensioning (but not rollers & water pump) but I think undertensioning would result in the same problems. I find it hard to imagine switching to a new belt without very convincing data since the exisitng belt does the job quite well (and inexpensively) as long as you tension them properly. The balance shaft belt is more expensive but I still doubt it would be worth the effort to tool up for the relatively small number of 944's out there....

technicolor

Forgive my ignorance, as I'm new to this, but why couldn't you just bring it to the same tension as you would a normal belt? Being kevlar shouldn't affect that, it should only reduce how often it needs to be retensioned.

That said, as long as noone thinks there is a real risk in this, I'd be willing to buy one (assuming the price is reasonable).

ClassJ

Might sound good on paper but consider this:

PCNA spent countless hours of testing, spent thousands of dollars, and applied years of engineering to determine the proper belt setup for a 944. If they could have made it last 100K miles they more than likley would have at that time.

Throwing on a new type of belt could throw a big wrench into the works. Kevlar could be great, could be bad. But usually, when you take a car apart for belts the water pump, rollers, and all the other usual stuff need changing (as noted above). Unless you can increase the life of those other parts, where are the advantages?

Maybe I would buy one, but let someone else run one through a life cycle first on their motor.

When someone offers a kit that lasts twice as long for about 50% more money and proves their claim with extensive testing, data, and matirials science that will perk my ears up.

Swagger93

Well, are teflon and kevlar the same thing? I didn't realize this (thought it was created from an experimental refridgerant that precipitated onto the side of a tank). I guess it also does depend heavily on whether the current rubber is synthetic or not, though I'd assume it is? I don't necessarily believe that enough stress is applied to a belt at any point while running to cause it to break; the only thing I could see breaking any belt (aside from age) would be something such as water pump failure, in which case the sudden stress exerted would most likely be great enough to reach the yield point of any flexible material one is using for the cam belt. If tension is a concern then that is an end-user problem, since they are responsible for making sure the tension is within a specified tolerance.

Furthermore, the quality control of a small company producing belts could actually be worse to the point that the benefit of a stronger material is negated. Right now the rubber belts are being produced in large numbers, so that may have some bearing on the consistency (or as some claim, the lack thereof) of the belts manufactured.

It's all about economics. I can't possibly see it being economical for someone to start producing 944 belts out of a totally new material at this stage of the game. I'm not sure what initial cost will be, but this is certainly far from a high-volume market.

That said, if there was sufficient test data to prove to me that the belt was superior and precisely manufactured...sure, I'd be in!

hosrom_951

How much longer does the Kevlar belt last, compared with the stock Conti belt?

What about the balance shaft belt?

BruceWard

I am interested in one for the 968 assuming the change interval is longer.

K27

All good points guys, thanks.

Tensioning would be the same, there is no reason to change tension, otherwise you effect timing and bearing life.

As kevlar belts exhibit virtually no stretch, retensioning would not be necessary.
These belts will easily go to twice the stock interval and some. Your water pump will also go to this interval. The rule of thumb has been to change the pump while you are there, not because of imminent failure.

Cost would be between $100-$150 which is in line with other similar products.

Some suppliers are quoting very long life expectancy for this type of product, it is however difficult to predict as it is very dependant on enviroment and driving style.
I think this is a moot point as the other components will probably fail long before the belt.
I will have more technical info and costs as I get it from the Mfg. and will keep you posted.

Thanks
Lance

theedge

I might me interested for my next belt change, since im about to do my belts now. This is assuming it does last longer.

Now a thought, if it doesnt stretch at all, or hardly at all, isnt that going to be far harder on the various bearings? Especially the waterpump?

K27

It will maintain the set tension far better, which should be to factory spec.
This would not cause any premature wear.

Mark944na86

The "rational" economic equation is not so much concerned the incremental cost of the belt, but rather the time between belt changes. A belt change is expensive because of the labour involved (yours, mine or the workshop), not the cost of the belts. If you can make a belt that can save you doing every second belt job, that's worth a lot - theoretically. According to this theory, you could add a hundred or even two hundred dollars onto the price of the belt, and all except the most time rich/cash poor would see it as great deal. Unfortunately, marketing realities, with price points, etc., make things more complicated -- people (markets) rarely behave precisely as economic rationalist models predict.

-Mark

Uranium-235

Teflon(tm) and Kevlar are not the same material. Teflon(tm) is polytetrafluoroethylene, PTFE, with a monomer of -(CF2)-, while Kevlar is an aramid, poly(p-phenyleneterephthalamide), PPT, the monomer has H, N, O, C and either benezene or phenol rings, I am not sure which.

I, personally, would consider paying $100-$150 for a belt that has been proven, and accepted, to last 100,000 miles. I don't mind retensioning and replacing belts, but why do it more often than necessary?

On the other hand, having to open your covers every 15,000 miles lets you see potential problems before they become too big. We drive 20+ year old foriegn sports cars, they need more attention than a Camry. And I am happy to attend my ladies.