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Bockscar · Joined: 16 Nov 2010 Posts: 392 Location: Sandy, Oregon

What exactly is the difference between the clutches on the pre-1982 924 Turbo and Non-Turbo? I know the spline count changes, the pressure plate is slightly different, and the throw out bearing is slightly different.
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Brian
'79 924 - Restoration In Progress
'81 924 Turbo w/EFI - Scrapped

!tom · Posted: Wed Nov 14, 2012 2:13 pm Post subject:

The short answer is everything.

Different bell housing, different release mechanism, different starter, flywheel, pressure plate.
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78 924 NA
5-lug

fiat22turbo · Joined: 18 Jan 2006 Posts: 4040 Location: Portland, OR

Exactly. Completely different.

Look at the parts diagrams for both styles and you'll see the differences.
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

Bockscar · Joined: 16 Nov 2010 Posts: 392 Location: Sandy, Oregon

Allow me to correct myself and answer my own question!

They are indeed completely different. Not compatible at all. In a nutshell, the clutch assembly on the NA models is a "push" style as in the clutch fork pushes the throwout bearing onto the pressure plate. For the turbo models, the operation is the exact opposite; the fork actually pulls the throwout bearing. I'm not a clutch or transmission guy so please feel free to correct me.

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Brian
'79 924 - Restoration In Progress
'81 924 Turbo w/EFI - Scrapped

fiat22turbo · Joined: 18 Jan 2006 Posts: 4040 Location: Portland, OR

Yup. The 911's used the same system (there is some part crossover apparently)

The 931 could be made to use a push type clutch assembly, but you'd need a new slave cylinder, flywheel, clutch and pressure plate. Likely be able to adapt a flywheel/clutch from an Audi of the same period. With that said, not likely to result in any gain whether monetary or performance, etc and the added headache of trying to get all of the various parts sourced and confirmed to work could be an absolute headache in the making.
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI

Not sure what led you to ask the question, but here is one thing to consider...

...you can interchange the Turbo clutch disc into an NA setup (or the cheaper Bronco II disc), which will allow you to convert over to the larger diameter torque tube, which in turn allows you to run a 931 or 944 gearbox in the NA. There are at least a couple of people who have done this conversion.
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erstwhile owner of just about every 924 variant ever made