Flywheel question?? Single, Dual??
Thread Starter
Racer
Joined: Jan 2003
Posts: 270
Likes: 0
From: Erie pa
Flywheel question?? Single, Dual??
I love the C4 tech thread. I learned a ton! I have a question about switching to a single mass flywheel like the post said. Are there any downsides? I was told the vibration can be really bad.
I am rebuilding my LT4 and am putting in a new clutch, and I was unsure if switching to a different flywheel was a good idea. My car has 92000 miles on it.
Can anyone chime in and give some real world pros/cons on it. I would really appreciate it.
Thanks
I am rebuilding my LT4 and am putting in a new clutch, and I was unsure if switching to a different flywheel was a good idea. My car has 92000 miles on it.
Can anyone chime in and give some real world pros/cons on it. I would really appreciate it.
Thanks
Safety Car
Joined: Dec 2002
Posts: 3,655
Likes: 24
From: Charleston SC
The single mass is fine but the alum Fidenza like I have is a huge PITA. If I had to do it all over again i would go with a steel FW. The alum FW chatters like crazy in reverse and is graby anyway. IMHO if your motor is fairly stock or even a mild cam such as the HC I would stay with the DM for everyday driving. I have a stage three clutch so it is a bit of on/off switch and my motor needs the extra grabing power but I still wish I had went with the steel SM. One other note is the single mass withthe ZF6 will make noise with the trany in neutral.
Drifting
Joined: Feb 2004
Posts: 1,485
Likes: 2
From: Champaign, IL
St. Jude Donor '05
I really like my Fidanza - it lets the engine rev a lot faster and makes a big difference. There is some noise with the clutch out at an idle but changing to a heavier trans fluid is supposed to take care of it. What's a little rattle .... I'm not driving a caddy this is my race car! 
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
the key is balance... you have to have the flywheels match balanced, no matter which way you go, steel vs. aluminum.
I have a fidenza and my only problem is the balance... I was too constrained for time, and didn't get it matched balanced, stupid me. I don't find it, using a stage 1 clutch, to be too grabby.
The issue is this: the dual mass flywheel is factory balanced as part of the rotating masses balance. You see, the crank is internally balanced in the front, and externally in the rear. The flywheel is both an engine balance, the springs in the pressure plate and a way of killing noise in the 6spd.
The technique is called "match balancing". The idea is that the new flywheel is balanced to match the percentage correction used on the factory dual mass.
The other solution, which since you are rebuilding the engine, is have the internals balanced. Do it right, and your engine will love you for it.
I have a fidenza and my only problem is the balance... I was too constrained for time, and didn't get it matched balanced, stupid me. I don't find it, using a stage 1 clutch, to be too grabby.
The issue is this: the dual mass flywheel is factory balanced as part of the rotating masses balance. You see, the crank is internally balanced in the front, and externally in the rear. The flywheel is both an engine balance, the springs in the pressure plate and a way of killing noise in the 6spd.
The technique is called "match balancing". The idea is that the new flywheel is balanced to match the percentage correction used on the factory dual mass.
The other solution, which since you are rebuilding the engine, is have the internals balanced. Do it right, and your engine will love you for it.
Safety Car
Joined: Dec 2002
Posts: 3,655
Likes: 24
From: Charleston SC
My rotating assembly was ballanced with the fidanza so ballancing is not an isue and I have no vibration what so ever once the thing is rolling it just chatters like mad trying to back up. It does seem to be geting better but If I where to replace the FW I would go steel
Thread Starter
Racer
Joined: Jan 2003
Posts: 270
Likes: 0
From: Erie pa
Thanks for the advice. My motor is going to be a 383 stroker with forged parts, hopefully shooting for close to 500 hp at the crank. I think the shop is having the flywheel balanced with the rotating assembly, whether it is a single or dual mass.
I spoke with ZFdoc and he said the single mass may vibrate in nuetral, but cuase no damage to the tranny. He seemed to think that the dual mass I have with 92000 miles on it should work OK. I guess I still am not sure what to do. I definitely want to do it right the first time!
I spoke with ZFdoc and he said the single mass may vibrate in nuetral, but cuase no damage to the tranny. He seemed to think that the dual mass I have with 92000 miles on it should work OK. I guess I still am not sure what to do. I definitely want to do it right the first time!
Safety Car
Joined: Dec 2002
Posts: 3,655
Likes: 24
From: Charleston SC
Originally Posted by spinedoc
I spoke with ZFdoc and he said the single mass may vibrate in nuetral, but cuase no damage to the tranny. He seemed to think that the dual mass I have with 92000 miles on it should work OK. I guess I still am not sure what to do. I definitely want to do it right the first time!
ZF doc is the man when it comes to the ZF-6 but there is no way in hell I would reuse a 92000 mile dual mass FW, been there done that. I reused my DM on my last motor and it was making a horible racket with in 1500 miles and I belive bogas may have had a similar problem. Over the last couple of days the alm Fidanza has been getting better about reverse, so I guess the clutch is getting better. You should get a hold of carolina clutch and talk to them if you want it done right the first time.
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