Its clutch time on my car (throwout bearing is making its expensive sound so im going to do the whole thing). Im thinking of a Fidenza along with a Spec Stage 2 from LR.

What im wondering is wether or not the Fidenza would increase or decrease the spool and lag on my car? Ive read posts on here going either way, and im thinking the heavier stock units would be better for spool and lag since theres a bit more load on the engine? Or am I looking at this the wrong way? I know it helps with the low down power (driven an MR2 Turbo with a lightweight flywheel, it was a blast) but im really wondering about the affect on the turbo.

Also, what about warpage? I keep reading people saying the Fidenza (or aluminum flws in general) warp with the heat, then I see that special tool and rage2 are running them with their big HP numbers, and I know rage2 tracks his car... Is the warpage only a worry in full out race cars that spend tons of time on the track?

 

Warpage is only a problem for guys who haven't tried them yet.
- and machinists who want to charge you to cut the steel ones

I never got any data on my car before the Fidanza, so I don't know about that one. Good question. I think the car accelerates faster, but not necessarily boost/RPM - the whole engine in general accel and deccel is faster.

 

That was the feeling I got about the warpage, I dont remember seeing any posts saying "Well my Fidenza warped... IM MAD" type thing

 

I've been driving around for about 4 months.
So, far so good but the decel is too fast for
my liking. Like you, I love to drive on the mountain
roads just across to where I live. You will find
that it's quite difficult to match rpm especially
when down shifting to second gear. For track
not a problem but for country or mountain
roads, I feel that it's too light.

 

Lightened flywheel really doesn't do much for power or for lag/spoolup, etc. It does a little for power, but very little. What a lightened flywheel does is increase the deceleration rate of engine speed when clutch is engaged. This allows you to shift faster while matching revs for smooth quick shifts. It also makes launching harder, as there's less stored energy when revving up, so you would need more revs than before to launch the car smoothly.

 

No shizzle! I am busting out 2.4-2.5 60ft times with either a bog or wheelspin at the moment... should have more luck this weekend.

 

Didnt you get your stock one machined down? Thats the other option im thinking of...

 

Machining the stock whywheel down is the direction I'd go. When I did my clutch job, we took the flywheel to a nearby machine shop and they turned it for $30. They only removed 0.006" from the surface, which could not have been more than an ounce or two, but I've read of others taking 5 POUNDS off the stock flywheel.

BTW, Brian, who's doing your clutch job? I'm happy with a guy who did mine right before the Hell's Gate gtg last August, for 9 hours labor and installing the new parts that I brought to him.

 

I am actually Im doing a whole pile of stuff in the same go, new turbo, new motor/transaxle mounts, Tial wastegate, ceramic coating the exhaust and maybe the intake manifold, SMT6 and Zeitronix are getting installed, replacing all the coolant hoses and the various fluid tanks, new brake pads/rotors, brake bias valve, the sport seats will be going in, front wheel bearings... And of course the clutch, which im happy about. I was ready to kiss my car for the throwout bearing grinding BEFORE I did everything else

I might just machine the stock one down. Ive read a bunch of posts of people getting it down to 8-10 pounds, and the MR2 I got to drive had a flywheel in that weight range and that thing was absolutly WICKED fun.

So tough to decide

 

Yes I did. Down to 8.5lbs from SFR.

Its certainly harder to get a good 1/4 type launch, but its not of concern to 99% of 951 owners!

 

Other things to consider: The individual combustions at lower rpm’s will be felt more with a lighter flywheel. It will also increase the peak load on the gearwheels (less smoothing of the torsional peaks). The ideal flywheel would have decreasing inertia as a function of rpm, but that’s a little difficult (= costly) to make.

Laust

 

Got any preinstall pics of it by any chance? I might just get my stock one machined down to about that weight. Harder 1/4 mile type launches dont worry me too much Knowing my luck id bugger it up anyway and be on here looking for a transaxle

 

So basically slightly more vibration? That I dont mind either Thanks for the technical stuff tho!

 

I just took pics of the KEP PP and cup disk, sorry...

 

Its ok. IIRC you mentioned that they got it down to that weight by taking off the inertia ring?