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Clutch Replacement

Old 07-20-2001, 04:43 PM
Roland Kunz
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Sorry but sometimes the page didnīt load, or this site was not accesible. Following my mailbox, I wasnīt alone.

1. Since the 1989 C4s are all using a single mass (solid) unit, are the early C4s having premature engine failure because they don't use the dual mass flywheel?

The early C4 had the torsion damper siting on the friction disc. Those units had a failure rate too ( ask Turbo drivers ). However since they went into the first 930 they where constructet to the final stage but Porsche planed pushing over that limit. The damper was to large for the coming 6 speed and to small for the coming engines. On the C4 with some 250 HP and 1700 kg wight they had been far from their constructet limit ( 320 HP turbo )

Porsche had to jump over that as the next engine generation was on the way and had close to 300 HP plus the 965 360+ HP. ( the original 380 HP AWD biturbo layout that came later in the 993 was stoped by Bez due to many resons, one was the clutch )

The Twin mass unit seem to be ( and is the ) soulution and Porsche was leading on that development only searching for partnerships. AFIR BMW, Audi, Mercedes, Freudenberg, Continantal, LUK and some others joined that pool and this startet way back in the 80īs as the 930 pushed the limit the 928 had trouble. BMW needed someting for there new V8īs and the V12. everyone had interessts and Porsche was some kind ahead off the crowd as Porsche is a small company where the engenieerers donīt have to ask a bank clerk if they need a new pencil ( and you get a sharpener plus extension ) and many things where done without documentation. Other companys go step by step but Porsche engenieering is simultanously or say parallel not seriel.

The Freudenberg units are not a engenieering flaw. The problem was the tooling and production from that design when it went into mass production and Porsche didnīt had been say aware off the problems that ocured with those items on the long run. The quality control just couldnīt detect the later failuring units. This is maybe today still not possible for the high tourqe demanding units and so Porsche donīt used them. But on smaller engines from other companys they work very well and BMW still uses them. They are much lower priced the the LUK units.

A typical US manufactorer will not need a DMF as they have heavy construction ( or say solid state ) and people drive an other way. Shake, rattle and roll is normal for a muscle car and if people donīt get that they will be disapointet.

The typical Porsche costumer will not like to buy just an other muscle car they like to buy a Porsche witch refelcts an own philosphy in the car world. An own caracter and having caracter is needed to own & drive the car.

2. Is there some type of difference engine-wise between the 1989 C4s and all the following model years (for example, different crankshafts and bearings) that would allow the early C4 engines to hold up better with a "solid" than later C4s would?

There had been some slight upgrades over the years but mostly reacting to occuring problems or integrating üpdates.

The 993 engines where on there way.

The LUK unit was constructet for the new 360 HP turbo and used on the later lightwight 3,8 turbo too. 993 TT has the same unit maybe too.
They boast someting close to 550 NM tourqe compared to the 310 Nm from the NA 3,6.

Thats enough reserves and I never had seen a failed LUK unit, the failure was most a exploded clutch or a darkblue colored surface

The 89 engines have a slight other DME wireloom slight other P&C and no gasket in the head.
Those items where shown and explained in the annualy Kundendienstinformationen.

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Old 07-21-2001, 04:05 AM
Bill Wagner
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I have a Freudenberg in my car right now (21K miles) and my own, limited statistics imply this will likely fail sometime in the next few years if not sooner (I'll likely put between 6K and 7.5K on the car annually). I've also read stories of complete success and complete disaster regarding light weight flywheel/chip combinations.

My conclusion (for myself) is as follows: If my Freudenberg fails, it will be replaced by a LUK. I don't want to take the risk of installing a chip/light weight flywheel because it may not work on my car AND there is some evidence that the combination may could lead to some premature engine failure.

That isn't to knock the light weight flywheel/chip combination, I'm just aware of the risks that this may not work on my car. This is a risk I'm not willing to take, for what it's worth.

Thanks to everyone!

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Old 07-21-2001, 02:12 PM
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Can anyone point me to a place to buy the andial unit and read more about it?
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Old 07-21-2001, 02:19 PM
Randall G.
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Hi Boris,

You can start here:

I just perused the site briefly, and only found the part listed--no detailed description. But, you can always send them an e-mail asking for more info. They seem to be pretty responsive.
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