300guy

I’m in the process of rebuilding the engine from my 1994 968.

I’m considering using a light-weight flywheel. I have done the research, and I understand that a lot of people that are using the Fidanza aluminum 968 flywheel experience a vibration at a certain RPM.

What are people opinions?

Here are my options, as I see it:

1. Use the stock flywheel
2. Use a Fidanza aluminum flywheel
3. Use a Fidanza aluminum flywheel and have the rotating/reciprocating assembly balanced (dynamic)
4. Switch to a 944 turbo or S2 flywheel and clutch setup

For option 4 I understand that there are additional implications such as: torque tube needs to be swapped, DME sensors may be affected.

The 968 flywheel is 30lbs! I reduced the flywheel weight on my 944 n/a by 2lbs and noticed a difference.

Opinions / relevant experience?

Thanks guys!

Damian in NJ

I think 9M in the UK offers a copy of the Porsche Motorsport lightweight flywheel?

cooz

pete from RS Barn will have a lightweight flywheel (approx 17lbs) available within the next 2 months. i believe it too is a copy of porsche motorsport flywheel

norm mandell

sasilverbullet

My opinion - If you don't track the car, use the original DMF and clutch setup. I've got 160,000 miles on my original DMF and clutch...you can to!

300guy

My engine has over 200,000 miles.

I understand that there are lightweight 968 flywheels out there. But they are still about 3X the weight of a 944 turbo aluminum flywheel! (18lbs vs. 6 lbs)

Is an S2 flywheel compatible with a 968 flywheel from an engine sensor perspective? (I realize that the torque tube and clutch/PP would have to be used from an S2).

RajDatta

300guy, yes that is correct. We used this setup when we turbocharged a 968. Went with an S2 flywheel setup using 968 trigger.
Raj

Jason Judd

Why would the lightweight 944 T flywheel be so much lighter than a lightweight 968 flywheel?

Are you saying that the lightweight 944 T flywheels are only 6lbs and the lightweight 968 flywheels are 18lbs?

Seems odd to me.

Jason

flash968

6 lbs does seem awfully light - even the superlightweight aluminum one i had for the mgb was 7 lbs

the fidanza aluminum one i have for the 968 is just over 12lbs

i believe the S2 flywheel is between 15 and 16 lbs - it is my understanding that it is a rather involved conversion

ehall

6 to 8 lbs is fairly normal for a lightened 951 FW.

Jason Judd

So why then is it that a lightened 968 FW is so much heavier?

Shouldn't we be able to get a 968 FW for something closer to the 951's weight?

Jason

ehall

Keep in mind that one of the problems 951 guys have is losing TOO much weight. Some go with lightened/knife edged cranks and others go with lightened FW/PP combos. Both will cause a significant issue with stalling at lights and easily over-revving the engine. (atleast slamming into the rev limiter anyway) Now these are 2.5 turbos and you guys are running a full 1/2 ltr more volume, but without the forced induction. I can only speculate that inline 4's @ 3.0 ltr are pushing the limits of harmonic balancing, thus a stout FW is necessary to prevent dangerous harmonic vibrations that would be felt in the cockpit as well as causing various issues with engine mounts, fasteners, gasket seals etc.

Jason Judd

Can you only imagine what it's like for the few of us who have 3.0 ltr turbos...

You should feel sorry for us...

Yep, our woes are bigger than yours.

Actually, it might not be a pretty picture for the track prepped 968 turbo...too much harmonic vibrations are probably not a good thing.

Jason

ehall

Yeah. I feel real damned sorry for you guys!

FRporscheman

When I need to work on my clutch, i want to at least try a lightweight FW to see how I like it. Thankfully a 968 allows the trial of a flywheel with little investment of effort.

ehall

Perhaps I should be a tad more clear. Folks ran into problems when they BOTH lightened FW/PP AND lightened the crank together. Those who have done one, or the other, seem to be happy with the modifications.