Is there a dual disk clutch setup for aircooled 930’s?

[Speedy Squirrel]

I’m talking two disks and one floating plate. Seems like the long bellhousing ‘78 and later 930 trans would be a natural for that. High torque, low pedal force, good for high RPM launch.

[matsuzaka]

I think smaller diam multiplate clutch are for racing, if that’s why you’re asking it makes sense.
I think for street it’s a bad idea.
Try driving a m/t 928 or 1st gen NSX or Carrera GT.
They have multi plate small diam clutches, once under way everything is great but taking off is where difficulties arise. They’re reluctant to slip and small diam reduces leverage to get car going.

[Tippy]

Originally Posted by Speedy Squirrel

I’m talking two disks and one floating plate. Seems like the long bellhousing ‘78 and later 930 trans would be a natural for that. High torque, low pedal force, good for high RPM launch.

KEP makes them.

I'd love to ditch my stage II pressure plate and only use a stock or stage I for lighter pedal pressure but still get great torque handling capability.

[kamaro]

Originally Posted by matsuzaka

I think smaller diam multiplate clutch are for racing, if that’s why you’re asking it makes sense.
I think for street it’s a bad idea.
Try driving a m/t 928 or 1st gen NSX or Carrera GT.
They have multi plate small diam clutches, once under way everything is great but taking off is where difficulties arise. They’re reluctant to slip and small diam reduces leverage to get car going.

The dual disc technology has solved the compromise between clamping force and the stiffness of the clutch pedal, with dual discs you get twice the friction area without increasing the clamping force, so you get more torque rating with a light pedal feel. In all my american muscle cars I NEVER use anything other than dual discs. I have always wondered why dual discs has never been popular in the porsche world, although the large bellhousing area for the later 930 and the G50 transaxles would be very encouraging to design a good dual disc system.

[David]

I like the light clutch idea but looking on the KEP website, they look heavy.

[Matt at Pelican Parts]

Pelican carries the SPEC brand and it looks like the stage 3 is a twin disk setup.
https://www.pelicanparts.com/More_Info/SPCSP043.htm?pn=SPC-SP043&bt=Y&fs=0&SVSVSI=784
But as others have stated with a higher stages comes a stiffer clutch.

[racing97]

I appears the spec is a push clutch and the 76 and 930 is a pull

reagards

[T77911S]

i have an 8inch triple disk in my race car.
was trying to turn it around in the drive way one day and it did not like the constant clutching i had to do. started to smell it.
yes great once under way but not a street driver.
yes very small and light.
i hate the size and weight of the 930 clutch. dont know what they were thinking on this one.

[Speedy Squirrel]

Yep, there are two ways to go. Small and lightweight with quite a bit of disengagement force, or normal sized with low pedal force.

[Speedy Squirrel]

Except that nobody seems to make a normal sized one.

[TurboKraft]

AASCO can likely make you a setup using Tilton parts and a custom flywheel.

[Porsche 935]

I called Tilton when my 934 style clutch would no longer hold the power and they wouldn't even talk to me.

[racing97]

Tilton only deals with their Dealers and more than likely for this they would send you to Aasco

regards

[Ollies930]

I always wondered if the 934/935 Sachs clutches for long bellhousings could be converted to a dual disc setup. If you look at the pressure plate inside the clutch, it has a long lip to push it towards the flywheel. If one were to remove that lip and thereby moving the pressure plate closer to the clutch spring, there might be enough room for another disc and an intermediate steel. The only question then would be if there is enough travel for complete disengagement.

[TurboKraft]

They can be.
The only downside is it is a heavy assembly, lots of rotating mass.
And it rattles and chatters in neutral or with the pedal pushed in.

[kamaro]

Originally Posted by TurboKraft

They can be.
The only downside is it is a heavy assembly, lots of rotating mass.
And it rattles and chatters in neutral or with the pedal pushed in.

Noisy dual clutches are long gone after they came up with the spring preloaded center plate, I've never saw a noisy/clattery dual disc clutch in the past 10 years or so.

[stownsen914]

Originally Posted by T77911S

i have an 8inch triple disk in my race car.
was trying to turn it around in the drive way one day and it did not like the constant clutching i had to do. started to smell it.
yes great once under way but not a street driver.

^ This. Tilton makes excellent clutches for racing. Use one on the street and you're asking for trouble. They overheat easily when getting the car rolling. Solid disks are a bit harsh too when getting the car moving in first gear. It would be an unpleasant experience overall using one on the street.

The one pictured above seems to have sprung disks, possibly a better option.

[TurboKraft]

Originally Posted by kamaro

Noisy dual clutches are long gone after they came up with the spring preloaded center plate, I've never saw a noisy/clattery dual disc clutch in the past 10 years or so.

I have, but those are in high power imports (Toyotas, Mitsus) and are probably race clutches or not top-of-the-line.
For the more streetable domestic stuff, like the Centerforce's DYAD and the McCleod RXT, I agree they are as silent as the stock clutch with very low pedal effort.

[Ollies930]

I talked to AASCO yesterday and the only Tilton clutches available are push types. Consequently, if you want a Tilton clutch, the clutch pedal will need to be changed from cable to hydraulic.
Spec has a stage 5 clutch for a 930, rated at 980 ftlbs, I am very curious about how stiff that pedal would be and how often the clutch cable would need to be adjusted/replaced and how hard that would be on throw out bearings?