944 auto rubber disc alternative

[porschke911]

I have come up with an alternative to replacing broken rubber drive coupler with a used clutch. I have an aluminum disc that is welded in place. I should have it operational in a couple of weeks. I just have to get the disc welded in place and then balanced. Disc weighs .5 pound so this greatly reduces rotating mass. This means more power.

[dgcantrell]

I'm interested in seeing how it takes the flexing that will occur. Keep us posted on how it works out.

[Jfrahm]

I'd rather see somehow bolting in a spring-centered clutch disk so it had some shock management, or at least bolt in the spring hub from one.

[porschke911]

There should not be any flexing as the drive shafts has a pilot bearing to keep it centered. The flywheel should be true so I don't forsee any flex. There also shouldn't be any need for shock absorbing as no other auto car has any shock management. All bolt to a steel plate

[dgcantrell]

I'm talking about the flexing from the torque... This is why most clutches have spring centered (or rubber) bosses to absorb the shock of engagement. A solid plate will offer no cushion to absorb the shock and will flex if the torque is great enough. How thick is the metal plate you're using?

[Jfrahm]

I do not know if the stock rubber disc was for just for NVH? There should be a flexplate out back. The 928 auto does not have a rubber mount for the front of the driveshaft but does have a flexible-ish triangular drive plate bolted to the flywheel:
http://billsworkshop.com/P928S4/endplay/endplay08.jpg

What does the old-school 924 use?

-Joel.

[flash968]

sure wish this would work on the 968. unfortunately, it requires damping. the manual trans car has the dual mass flywheel, which provides damping. the tiptronic has the rubber disk, which provides some damping, but not as much as the DMF, which is why all tiptronic cars vibrate.

i played around with clutch disks for the 968, when i was messing with the solid flywheel, and without damping, it was horrible.

hope it turns out better for the 944

[porschke911]

I don't see a problem with installing a spring centered hub from a clutch disk if it turns out that I need dampening

[dgcantrell]

On second though, being an automatic, the torque converter may provide enough dampening that you may not need to.. Very interesting. How thick is the aluminum disc?

[porschke911]

I'm using a 3mm aluminum alloy. My thought was that it is strong enough to take the power yet flexible enough if there is the need to flex. I have the same thought about the auto, that the tc should provide any needed dampening. I am still keeping options open as this is my first prototype.

[dgcantrell]

I'd keep an eye on it and inspect it for cracking every so often. Definitely keep us posted on this. I don't own any automatic 944's. I don't plan on it either but you never know, I've been known to do things I said I wouldn't. I've seen me do it... LOL

[jeffrsmith]

I would certainly want some damping at the flywheel end, even with a good damper disk in the front the torque converter mount plate has been known to have an issue with cracking.

[Arizona_928]

hmm and i was expecting a chevy truck disc.

[Jfrahm]

Hmm I dunno. I'd hog out the middle and bolt in a Ford Ranger clutch disk.
You can feel the difference in NVH between a rubber and spring center clutch in a 944, this plate is likely to transmit more NVH than a spring disc and that NVH can't be good for the torque tube, rear main, main bearings, thrust bearing, etc.

[flash968]

based only on experience with the 968 setup, i know that one of the problems of a lack of damping is that all of the bolts come loose. it was pretty scary.

[Rasta Monsta]

Originally Posted by porschke911

There also shouldn't be any need for shock absorbing as no other auto car has any shock management.

That sure isn't the case. Look under any BMW.

[zedsn]

I have seen threads where people run a 5 speed 944 flywheel and clutch and bypass the auto rubber dampener that way.

[porschke911]

Sorry for the delay in updating everyone. The tranny went in my half-ton truck so I had to rebuild it. I also couldn't find a shop to balance the drive plate so I made my own balancer. I got the car back together yesterday. The drive plate works great. Totally smooth. I'm going to take the car to our local race track once it opens for a good test.

[porschke911]

Originally Posted by zedsn

I have seen threads where people run a 5 speed 944 flywheel and clutch and bypass the auto rubber dampener that way.

I was going to go this route but found the increase in rotating was going to be great and these cars are not fast to start with. My fix decreases the weight so it increases the performance

[dgcantrell]

Cool.. But the real test will be over time. I'd keep an eye on it and inspect it periodically to make sure the plate isn't developing cracks due to any flexing that might be taking place. Definitely keep us posted on how it does..

Got any pics of the final product before you installed it?