Yet another LWFW thread.....
Yearly I place about 2000 track and roughly the same street miles on my 2005 997s(Very early model)
Due to various issues, the clutch is back out and the flywheel needs to be replaced.
I’ve read a lot of negative posts about the LWFW (Light Weight ‘Single’ Mass Flywheel) presumably causing catastrophic failures with these engines. The negatives seem to originate from one presumably knowledgeable source + a Porsche TSB. On the flip side, I’ve also read about quite a few DMFW (Dual Mass Flywheel) failures, although not as catastrophic, still very problematic and annoying.
There seems to be some question if the 997s might have a front/pulley based balancer of some sort that may minimize balance issues due to a LWFW, thus minimizing the danger. If anyone can comment on this aspect, please do.

My goal is to have the car as reliable as possible for track use. I hate losing track time due to mechanical issues. (That’s why I left Corvette… So far for me this has been a very bad decision)

Lots of sub questions……
1) Does the LWFW help normal driving 1-2 shift from jerking around.
2) Do most people (Especially mechanics) believe in the LWFW=cracked crank relationship? There seems to be so little data that statistically I’m not sure… I’d hate to imagine the engine is also that unbalanced and delicate.
3) Anyone know if the 997s has some sort of front pulley based Harmonic Balancer? If so does this in anyway elevate the concern of crank shaft failure?
4) Is there possibly less shaft rattle from a 997s with a DMFW vs a 996?
5) Do other people view the DMFW as a reliable issue?
6) Who out there actually has a 997s with a LWFW and tracks their car regularly?

 

I am not a mechanic, although I am told by various people including Alex @ Sharkwerks that the M96/M97 engines have a different pulley system and don't have the harmonic issues thy the GT1 blocks do. I have seen the M96 engine that has presummably failed do to the LWFW, but in any manufacturing situation you will always find a failure in some way.

I do track my car, a lot, and love how the LWFW has helped. It gets to the higher engine speeds sooner, smooths out shifting (up and down) and has done so without failure. My DME scan would make almost everyone run from this car, but it is wickedly fast, and has been on my car for over a year and a half.

If you want more technical info, contact Alex at Sharkwerks, he knows his stuff.

I would buy it again if it makes a difference.

 

NorthVan, How many track miles do you think you put on your car each year?
Also do you get much in the way of rattle?

 

There is a little bit of extra noise, however I hardly notice it over exhaust sound.

As for track milage, last year it was about 3000 miles on the track, and I run it very hard, I was going through OEM rotors in 2-3 track days (spider cracks).

 

NorthVan - I had troubles with idle when the LWFW was installed in my 964, to the point where I could not run my A/C. I liked it enough that I kept it, and when it failed, replaced it with another.
Are there any idle issues with the 997 and your LWFW?

 

I don't have any idle issues, and from what I am told if it did change the effects of the cars idle, the ECU is able to adjust for it and keep your car running smoothly. The only side effects that I have is a little rattling noise (more mechanical sounding, like a GT3RS), and quicker acceleration. This has been my favorite mod, it has changed the way the car reacts.

 

What brand of LWFW did you choose?
Did you get a sprung or unsprung clutch?
Do you have any issues starting from a stop, (Say in stop an go traffic)
Do you think it will have a negative effect on resale value?

 

I have an Aasco LWFW. I am running an OEM clutch, it handles the power very well.

The LWFW and OEM clutch is easy to drive in city traffic, I actually find it easier to drive in the city.

 

I also have the Aasco flywheel and stock clutch...installed by TPC. There is a little rattle at idle, but big improvement in how freely the engine revs. There is also a better response when blipping the throttle during down shifts.