Light Weight Pressure Plate Use

[toms930]

I plan to install a new Clutch and Pressure Plate on my 88 930.
Can anyone offer advice on the Pro's and Con's of using the light weight Aluminum Pressure plate with adapter ring vs. the stock
steel PP? The car is street driven, occasional DE use and is stock except for cat bypass pipe and one bar boost spring.


Thanks,

Tom

[David]

You'll probably notice a little better acceleration in 1st gear. Of course it's also a bit harder to get off the line. I went with a Patrick Motorsports steel lightweight flywheel due to the added heat in a turbo clutch. So far so good.

[Lukesportsman]

David:

More heat, from more horsepower? Were you thinking heat sink or cautious of Al for other reasons?

Tom:

You were asking pressure plate, though correct? I am also curious and am in early stages of this research. Many seem to be quite happy with KEP Stage I.

[David]

I know my OEM flywheel was toast when I removed it and I've seen other 930's in the same condition. I've never seen a NA flywheel look as bad.

EDIT: opps, I was thinking flywheel not pressure plate as mentioned in the original post. Yes I've got an aluminum pressure plate and a steel flywheel.

[Lukesportsman]

Do you think the tall 1st gear is part suspect in this? Is this with the stock disk and pp? I'm just thinking out loud about what/where the problem lies. There are certainly other high torque cars with Al flywheels. The friction surface is steel and I'm thinking Al may have less capacity for heat but yet radiates heat quite quickly (faster, I think than steel).

I'm just more suspect of clamping forces and pad/material design of factory rubber hubbed clutch. Any thoughts?

[David]

I think there's so much power under hard acceleration that it's a fine line between spinning the tires and slipping the clutch. An aluminum flywheel would dissipate heat faster but I think the thin steel insert would overheat before the heat could be dissipated.

A tall first gear and a light clutch/flywheel doesn't help either. I left a stoplight while breaking in my engine, gave it just a hair too much throttle with the clutch pushing in a little too much, and wham... the engine spun up like it was in neutral.

[Lukesportsman]

Good point, David. Just the fact that there is a dissimilar metal interface is going to complicate issues. I'm running Al flywheel on NA app but may certainly rethink this for turbo app. So the question of weak point probably comes down to the durability/thickness of the steel working surface. I wonder what kind of mechanical contact the two materials have, though I suspect its just two machined smooth surfaces that are attached with fastners.

I wonder if one increased the surface areas and maximized the contact....