Fidenza flywheels....Q's

[rickharrison]

So this discussion on NA improvements has me wondering...when I eventually do a clutch again, what are the performance benefits of something like a Fidenza lightened flywheel anyway?

[flash968]

reducing the rotating mass at the flywheel does TREMENDOUS things for acceleration - how much of an effect it has on a particular car can be calculated, depending on the car's weight, horsepower, tire diameter, existing 0-60 times, etc

it will be far more effective in lower gears than higher ones

it will require re-learning how to take off and shift - it will have a tendency to stall if you don't get it right when launching, and will require learning to speed match the gears on downshift - it will also require much quicker shifting if you want the shifts to be smooth - the car might also actually "feel" slower out of the hole, but you will in fact be quicker - the lack of mass fakes you out, but the tach will tell you the truth

i have one on one of my 968s - the effective weight loss was like taking nearly 400lbs out of the car in 1st gear, down to very little in 6th

lots of fun in a weekend toy, but NOT a good idea for a commuter car - very hard in traffic

also, due to the nature of the reduced mass and resultant resultant speed differential, you will shorten the life of your clutch disk by at least half - do not expect to get more than 40k miles out if it

[ScoobySteve]

Originally Posted by flash968

i have one on one of my 968s

How many do you have?

OP:

I don't have any experience with 944 lightened flywheels, specifically, but I do in other cars.

Every car and every driver is different in terms of drivability. If you are used to vehicles that require a bit more dexterity to start off in anyway (vehicles with more sporting clutches, AWD, no low-end torque, etc) I don't imagine you'd find a lightened flywheel in the 944 to be too difficult, even as a daily driver, if you don't commute with a lot of stop-and-go driving.

With that said, there's also the huge psychological improvement. Out of gear the motor will seem 100x more rev-happy. That alone will make it seem...happier and more eager to go driving.

I would see if you can find anyone near you who has one and try it out as it's very much a personal preference. What might be fine for me may be unacceptable to you.

[flash968]

i have 2

the 944 is very soft in launch, and doesn't have a lot of torque to begin with - the lightened flywheel will make for very free revving, which can be both good and bad, depending on your pedial dexterity

i've been running light flywheels for 30 years, so i'm used to it - other people may find it to be too much - it's a very subjective thing - my wife won't drive the car because of it - she keeps stalling it and her shifting is herky jerky - it's not because she can't drive a stick either - that's all she drives, and her daily driver is an E46 M3

i would highly recommend driving one first

[Techno Duck]

If you are worried the Fidanza will be 'too' light, you can have a stock flywheel turned down between 8-9lbs. I had my stock 951 flywheel which is 15lbs about (n/a is the same) to 8.5lbs locally for about $100.

The difference is very noticeable and i like it alot. Rev matches are much easier (i rev match, heel toe every downshift even on the street), shifting is also crisper as the revs come down much quicker. Not any harder to drive in traffic or get the car going uphill. I was originally going to do a Fidanza (About 6-7lbs) but decided against it as i get stuck in traffic often going to and from the track.

If you go with the Fidanza, make sure the crank trigger depth is set correctly and you loctite the stud. Also MAKE SURE you have the flywheel balanced. A few grams at 6k rpm translates into a major imbalance. Another thing is to make sure the crank trigger is in the correct spot, a local track buddy of mine had problems with his car attributed to the crank trigger being in the wrong spot!

[rickharrison]

I think doing a grind is probably the best of both worlds for a street driven car then.

thanks!

[mistertate]

From the Fidanza application guide:

944 NT 81-88 2.5L Except S & S2 199001 6 229001

The S flywheel has a toothed crank trigger ring so unless you're going to get your crank signal somewhere else the NA or turbo flywheel won't work.