I have been researching my upcoming clutch job as pertains to the clutch job and had a few thoughts. It seems alot of people complain about the noise associated with the LWFWs available. All of these flywheels are aluminum. Has anybody ever thought of making a single mass steel flywheel to act as a good compromise between the anoying rattle and the sluggish revs of the DMFWs? It would be slightly heavier than aluminum, but still lighter than the DMFW. Any thoughts or input?

 

The 964 rs flywheel is single mass and still makes the rattle. It is the same wheel that UMW uses and the 997gt3RS. I have one and can weigh it tomorrow. The reason for the rattle is the rotating mass is not enough to smoothly rotate the motor at idle. every 120 degrees of rotation is a compression stroke and the mass of the dual mass wheel is high enough that it does not allow the crankshaft to slowed down. By not slowing the gears do not get to backlash, thats the rattle noise. Please forgive me if you know this already.

 

Tim, the 964 102 239 31 flywheel is 12.8 lbs.

 

Interestingly, the 964 flywheel causes significantly more rattle when applied to the 996TT and GT2 compared to the GT3RS...or even 997TT when it is converted.

On the 997TT conversion, when you push the "sports" button, several engine parameters change....what little rattle is present at warm up becomes even less so when the clutch is out at idle.

 

That is odd as the compression is higher and the crank, rods, and valve train are so much lighter on the gt3rs. Is the idle higher?

 

No. I know that many 996TT setups require a reflashed idle RPM to prevent stalling...I have yet to see a 997TT require the same. In a completely stock car, even the exhaust tone will change when you engage the sport button. Timing, boost request, and and the throttle map are altered...but I can't explain why the rattle would disappear at idle.

 

Can a lwfw cause any damage? Or is it just annoying rattle. Someone told me it rattles like a dry clutch on a ducatti.

 

i would like to say following... lwfw under race conditions is better for engine and transmission, but under daily drive conditions transmission dont like it real and at idle with ac on engine and transmission dont like it.. in other words above 2000rpm lwfw, but under 2000rpm nothing better than a dualmassflywheel... both a the same time isnt possible

but i dont hear from any issues from a lwfw


with a lwfw in low gears your car feels like much more hp, if it revs much better, but you pay the price with sound of a racecar

 

My 964 flywheel weighed about 13lbs. You will almost definitely get used to the "rattle", and not even care after a while, when you see how much quicker you seem to rev. Your engine will also be happier not spinning the stock ~34lb flywheel. I opted to never run an aluminum flywheel on my 996tt.

 

i have tried following:

hot transmission ac on at 1100rpm idle and no rattle

hot transmission ac off at 1030rpm idle and no rattle

cold transmission no rattle at 750rpm/that is the situation i am dreaming with lwfw...i tried 75w-140 oil but it helps only a little

i am told at a porsche ecu idle can only adjusted to 1000rpm...a little compromise but it helps

next problem is hard load under 2000rpm it rattles again/sprung clutch doesnt prevent from that rattle and is very recommend if you drive on street

this is only experience on gt2 / on a 996tt it is a little better situation

 

I tried a lot of things too. Shockproof oil seemed best to me. Windows down with a car next to you at a light is when you really hear it though.

 

Is the 964rs fw steel or aluminum? The weight differences between the two materials are substantial.

 

i agree 100% with you , oil is the only medicine against the rattle...but what oil is the best

 

I don't find the rattle any big deal. It doesn't seem that bad to me. If anything, it just advertises that you have a light-weight flywheel mod.

 

agreed. someone would really need to know what it is to hear it. All the talk about making the car sound "broken" is BS (at least with the setup i run).

Kinda like IMS noise really...