I've also thought about a lightweight flywheel. I already have the Sachs Power clutch, but I've never attended to a lighter flywheel. The one Pelican sells for my style 915 box is 41% lighter.

So some questions:

1) On hills, I imagine I'll be slipping the clutch more and reving the engine higher to get going, correct?

2) How complicated is it to replace the flywheel? I've never personally replaced my clutch, but I'm assuming both the clutch and flywheel are in close proximity, and with that, figure the engine and trans has to be dropped.

3) Does anyone have any experience with the Pelican Parts lightened flywheel?

Thanks everyone.


SmileWavy

1. Lots of better things to spend the $$ on.

2. No performance benefit, really -- unless your lap times are seriously impacted by the time it takes you to shift.

3. It's fun!

Add it up...

Randy - thanks for the advice. As is, I have a short throw in a short-geared 915 (7.31), which tools around town fine, but keeps the revs up well on the track - so good advice, indeed. I guess the only thing left would be lower profile tires in the rear (45 vs 50-series).

Jeez...it seems I'm running out of things to spend money on. :(

I can help with your first question. The PO replaced the FW and clutch at the same time prior to my purchase so I can't answer the second.

I don't have any problems with my LWF on hills. You can feather it the same as with the stock flywheel. However, on steep hills or any hill where I have to remain stationary for anything over a second or two, I always use my handbrake and put my car in neutral. That seems to help reduce the wear. On my SC, I got 101k miles on my first clutch and the current one has 109k miles on it, although I think the time to replace it may be coming up.

I've had two separate Porsche mechanics drive my 993 and confirm it is very quick as compared to a stock 993. How much of that can be attributed to the LWF and how much to the fact that I have RS gears is uncertain. The combination however works well together. If you were in my area, I'd let you try driving mine. I think driving a similar model car with similar options you now have except for the LWF is the best way to confirm what the feel is like for yourself.

I don't think I would replace a perfectly good FW just to get the LWF. But if I was in changing my clutch, going to a LWF has drivability benefits. The car revs much quicker. I have only driven a 993 with the LWF so I would recommend driving a car similar to yours with the LWF and judge for yourself.

I just removed mine last week.
here is a 10lb version that is now out:

http://forums.pelicanparts.com/uploa...1152714245.jpg

Okay, thanks guys.

The Patrick MS LW flywheel for a G50 looks like this

http://i14.photobucket.com/albums/a3...ernau/LWFW.jpg

It may not be representative for 915s but the amount of material removed is not that much. As Souk suggested above, I went for an Aluminium pressure plate and a 930S clutch on my G50. Its substantially lighter and everything spins up faster. I also rebuilt to a spec producing 40hp more so its hard to say if the clutch/PP change has made a lot of difference.

Kennedy Engineering also makes a light weight PP with a high clamping force.

There is a heck of a lot more rotating mass in the pressure plate than the flywheel folks. Ask yourself when you want the engine to make power? When it's coupled to the tranny? Or when it's free spinning?

I have no doubt that there is a performance benefit to a lighter flywheel, but is it a practical solution to your desired operating conditions? Some of the points needed to make that decision has been posted on the thread.

With the light PP (and stock flywheel), your engine will behave just like it always has....but when it's coupled to the tranny it will have to do less work. INERTIA....less of it.....

911-32: which alum. PP did you get for your G50?

What is that FW for?

I'm telling you...call Tyson at Wevo..they have a great setup..and he's a straight shooter.

Honestly, it's not a good investment from a performance per dollar point of view. And, for an older transmission, like a 915, it's probably better to have a stock flywheel, as your shifts will be slower and better for the transmission.

Maybe search the classified/ebay to help with the performance per dollar ratio?

The flywheel is part of the rotating mass like anything in the drivetrain, up to and including the drive wheels and tires. It's the same effect as having lighter pistons, con rods and crankshaft. Less rotating mass means there's less resistance (momentum) to change speed which results in faster response from the throttle. All good for a track car that spends minimal time starting from 0 mph.

As stated, a lightened flywheel in a street car can make starting from a stop more sensitive due to the reduced inertia provided by the lightened mass. A light pressure plate provides the same effect, but unlike a lightened flywheel, you have to replace it with another expensive unit when it wears out (or else have it rebuilt).

Sherwood

1967 2.0 S motor.
(it went along with an aluminum PP and 69 clutch disk)

old weight was 20lbs for the entire combo- including flywheel bolts.

replacement part was tilton 5.5inch... 14lbs including bolts and all disks

brant

new set up
6lb flywheel, 8lb clutch
Net is 6lbs savings:

http://forums.pelicanparts.com/uploa...1152724270.jpg

Thanks Brant. I saw the 2.0S in your signasture, but didn't want to assume it was for that drivetrain.

Sherwood: a worn lighter flywheel has to be replaced too (or shaved...eventually to the point that it must be replaced) ;) As you mentioned a PP can be refurb'd.

I think it's all a moot point unless someone is willing to spend a lot of money for the small gain. By small, I mean that it is small relative to the HP/$ gain from internal engine work. The thread starter has a hot rodded engine already. Someone looking for performance gain simply by installing a LW flywheel and/or PP....is probably better off spending the money on something else. BUT! If money and its gain/cost ratio is no issue, by all means, shed all the mass you want. That includes anything that moves.....which is the whole car :D

I'm not trying to be contrary to any of the posts. Just wanted to point out where the lower cost (time, money, convenience and operating efficiency) gains are to be had.

I can agree with this statement.
and I can admit to hijacking the thread also...
racing is always about working within confinements.
(otherwise we would all have 22Liter engines right?)

Lightened flywheels are kinda fun to drive, but perhaps not the most cost effective upgrade.

the most cost effecive upgrade would be a larger motor'd car or else, racing tires.

brant

when it's coupled to the tranny [there will not be any significant reduction in] INERTIA....b/c the inertial forces will be dominated by the tires and the ton or more of car they are trying to move...

You are buying fun. That's pretty much it.

And there is nothing wrong with that...

I'd go for the lighter PP first, BTW.

By that reasoning, the LW flywheel and anything that is LW between the wheel and the top of the pistons would not worth changing for mass reduction. :)

Yes and no. Gear reduction ensures the flywheel/clutch has to accelerate up to much higher RPM than everything behind the transaxle. Therefor each pound of flywheel introduces more rotational inertia than each pound of tire/wheel etc.

The ratio depends on the gear selected, but consider the flywheel might need to spin up 10x faster in lower gears than the wheels.

Who wants to do the math?

Good pt. Chuck.

But I'll leave that math to someone else...

Math? Don't look at me! :p