Hi Everyone, the most recent talking on this topic I could find starts a long time back so I just wanted to get the most up to date opinion. For anyone who remembers I bought a car which had been stored for 20 years and now the independent shop who are excellent (Boxerwerk in Munich) are doing a massive service for the TüV inspection. The flywheel is knackered. Totally. Porsche don't make them anymore but they managed to find an original part for €1K. But then I thought is this not an opportunity to replace it with a lightened version to increase driving pleasure?

So, the question I have is will it? Is a lightened version an improvement? Does it changes the driving much (its a manual gearbox of course)? If I get one do the guys need to make any other changes? As ever I highly value your varied opinions.

 

IMO, the 928 manual flywheel is not that heavy, and making it lighter wouldn't make much sense unless you're also lightening the other rotational-mass items.

Just go stock, and you'll never have to worry about it again, unlike some aftermarket parts which haven't been adequately tested and vetted.

 

I agree completely.

Can't really speak to the other models but I always thought the flywheel on mine, if anything, seems to be on the lighter side.

 

These guys are right. The factory flywheels on all models really don't have much mass. On the later cars, it's that monster pressure plate in the clutch assembly that is the boat anker.

If you are trying to save weight, you can look at a twin disc swap, or some of the aftermarket options that do not use the GTS/S4 clutch assembly.

 

Indeed. This is the reason why a friend of mine made a lightweight pressure plate. But it was too expensive and I don't think that he will produce another one.

 

Our flywheel for our single disc and dual disc replacement clutches is actually heavier than the stock flywheel. (However, our flywheel incorporates the starter ring gear, where the stock set-up has the ring gear on the pressure plate.)
Of course, our pressure plate is significantly lighter (aluminum) than the stock pressure plate, so the total weight of the two is about the same as the stock pieces with our dual disc set-up.

Our single disc assembly (made for relatively stock 928 applications) is much lighter than the stock late model 928 assembly, due to the removal of the 7 pound intermediate plate and the 3 pound additional clutch disc used in our dual disc set-up.
You can definitely tell the difference when "free reving" the 928 engine between our single disc clutch assembly and the stock 928 clutch assembly.
That 10 pounds really does make a big difference.

Keep in mind, however, that the 928 crankshaft weighs right at 60 pounds.
Add in the heavy stock connecting rods and the heavy pistons and that's a whole bunch of mass to accelerate, regardless of the flywheel and clutch assembly.
A 928 is never going to rev like a high compression 2 liter 911 engine.....

 

Once upon a time 928 Motorsports made an aluminum flywheel. You can read about that here. 928MS is no longer making it, but it looks like you can still buy one here. You can order one from https://specclutch.com/ as well. I seem to remember they were making them for 928MS but don't hold me to that. They may require a timing ring from an automatic.

If you are interested in a dual disc setup for your GT, PM me, I have a new setup and the custom flywheel needed.

 

The gearing is realllly not going to make a light flywheel any different than a stock one..it's not a quick revving drivetrain.

 

The flywheel and drive plates are available from Porsche, for a combo of about $1500. The flywheel was superseded to CX

 

Hi,
the flywheel is 399,20€ and available.
A service-Kit for the clutch is also available for 1599€
Where is the problem?
May be your Boxerwerk is not that good working on a 928
Always remember: a Specialist on 911 is not a Specialist on 928
Berlina

 

Thanks great offer. Ive sent you a PM.

 

Bonjour,
I found in a post somewhere in this forum that the flywheel of the S4 manual, new (same as GT) weight 5,22Kg (11,5 LBS).
When I examined my flywheel during rework, it had a deep groove made by the clutch disc and big cracks...
So I made it machined. After machining the thickness 1 of the flywheel, see WSM page 13-10b, is 27,8mm so very close to the 27,5mm limit defined by Porsche. After rework the flywheel weight 4,464kg (9,8LBS). I kept this flywheel as a spare for next engine rework.
I had an other used spare flywheel that I asked to be machined too and balanced with the crankshaft. After machining the flywheel had a dimension 1 of 28,5mm and the weight is 4,738Kg (10,4LBS). It is the one I used on my reworked engine.

So if you rework your flywheel to minimum thickness, you will win about 0,8Kg (1,7LBS), the weight of 1 piston!
Cheers,
Raphaël

 

Hi All - based on the high valued opinions here I decided to go stock and the workshop managed to find a Porsche original part in an orange finish.