Flywheels 101 - Single mass/dual mass - what's the diff?
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Flywheels 101 - Single mass/dual mass - what's the diff?
Just reading in Oct C&D about the 911 gts rs (not coming to these shores). They talk about the standard dual mass vs. high perf single mass & it got me to wondering about my LT4.
Is the flywheel in the LT4 single or dual mass? Why? What does dual mass do for you?
Thanks for any answers to this admittedly basic question. :crazy:
[Modified by froggy47, 6:43 PM 9/4/2003]
Is the flywheel in the LT4 single or dual mass? Why? What does dual mass do for you?
Thanks for any answers to this admittedly basic question. :crazy:
[Modified by froggy47, 6:43 PM 9/4/2003]
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Re: Flywheels 101 - Single mass/dual mass - what's the diff? (froggy47)
I don't know too much about it, but the LT4 has a dual mass, as do all ZF6 Vettes. It is supposed to keep it from being too noisy.
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Re: Flywheels 101 - Single mass/dual mass - what's the diff? (LT4 2 Fast)
the alum single mass flywheel weighs about 12-13 lbs. It is much lighter.
Robin
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Robin
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Re: Flywheels 101 - Single mass/dual mass - what's the diff? (froggy47)
Here's a pic of a single(camaro in this case)left and a DM right.
What I think is the main thing is cost of the DM. ALOT more than anything else when time comes to replace it. They can be resurfaced(my old one was twice) but stand a good chance of ruining the thing internally. Also as noted, the DM weighs like 45 lbs.! I installed the single above and yeah, it sounds like a box of rattling rocks at idle in nuetral. I don't care. Launches at the strip w/ the single are also alittle more challenging than with a DM. Also lack of clutch disc replacement options. Notice the single is recessed in the middle. This allows sprung center hub clutch discs. The DM won't. It has it's own springs inside. Us L98 guys have to contend with the balance issue thing also:
Now that I can use sprung hub discs, I tried the SPEC III carbon fiber with slicks at the track. It did very well, but it wore out in approx a year. I just got a McLeod disc recently(kevlar) and I'll so that does pretty soon here.
I'm not too familiar with that other car ya mention, but maybe sounds like it has a tranny made by ZF?
[Modified by 89 Paul in Cal, 7:21 PM 9/4/2003]
What I think is the main thing is cost of the DM. ALOT more than anything else when time comes to replace it. They can be resurfaced(my old one was twice) but stand a good chance of ruining the thing internally. Also as noted, the DM weighs like 45 lbs.! I installed the single above and yeah, it sounds like a box of rattling rocks at idle in nuetral. I don't care. Launches at the strip w/ the single are also alittle more challenging than with a DM. Also lack of clutch disc replacement options. Notice the single is recessed in the middle. This allows sprung center hub clutch discs. The DM won't. It has it's own springs inside. Us L98 guys have to contend with the balance issue thing also:
Now that I can use sprung hub discs, I tried the SPEC III carbon fiber with slicks at the track. It did very well, but it wore out in approx a year. I just got a McLeod disc recently(kevlar) and I'll so that does pretty soon here.I'm not too familiar with that other car ya mention, but maybe sounds like it has a tranny made by ZF?
[Modified by 89 Paul in Cal, 7:21 PM 9/4/2003]
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Re: Flywheels 101 - Single mass/dual mass - what's the diff? (89 Paul in Cal)
Paul, Porsches have been using dual masses as well for at least as long as Corvettes have. Porsches dual masses have the same problems with eventually breaking down and rattling too...
[Modified by Red 90 L98 Coupe, 12:45 AM 9/6/2003]
[Modified by Red 90 L98 Coupe, 12:45 AM 9/6/2003]
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Re: Flywheels 101 - Single mass/dual mass - what's the diff? (89 Paul in Cal)
Absolutely great pics! So why DM? Does it smooth out the launch/idle? Provide more torque (more mass spinning? Now that I can see what it is & the differences, the ques is what does it provide in advantages/disadvantages. One dis already stated is it costs more. Second is it weighs more. Must be some reason gm puts them in our cars.Thanks!
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Re: Flywheels 101 - Single mass/dual mass - what's the diff? (froggy47)
It is called a dual mass because it is actaully 2 pieces.
These 2 pieces can move about 1/4 an inch of eachother. this is what eats up the noise in the tranny. without the dual mass you get a rock crushing sounds with the clutch out at idle. each trans is different.
I feel this is GM's number 1 reason to go with the dual mass, to get rid of the tranny gear noise.
As a side effect, the DM it will ease launching.
My dual mass weighs ~35 pounds, my single mass weighs 15.
I think the supra TT has a dual mass as well.
These 2 pieces can move about 1/4 an inch of eachother. this is what eats up the noise in the tranny. without the dual mass you get a rock crushing sounds with the clutch out at idle. each trans is different.
I feel this is GM's number 1 reason to go with the dual mass, to get rid of the tranny gear noise.
As a side effect, the DM it will ease launching.
My dual mass weighs ~35 pounds, my single mass weighs 15.
I think the supra TT has a dual mass as well.
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Re: Flywheels 101 - Single mass/dual mass - what's the diff? (bill mcdonald)
Thanks for the post. The more I explore this single vs dual question, the more questions I have!
So, the dm quiets down the tranny & the sm tends to be loud (rocks crushing).
I've owned several cars with std tranny, some low perf. & some higher (1984 Toy Supra - 5 speed - if I recall)
Is the single mass on a Vette loud because it has so much hp/torque? Those older cars I had with regular flywheel did not seem loud at all.
Maybe the 84 Supra was a dm, I have no idea. It was very quiet & smooth in operation.
Thanks.
So, the dm quiets down the tranny & the sm tends to be loud (rocks crushing).
I've owned several cars with std tranny, some low perf. & some higher (1984 Toy Supra - 5 speed - if I recall)
Is the single mass on a Vette loud because it has so much hp/torque? Those older cars I had with regular flywheel did not seem loud at all.
Maybe the 84 Supra was a dm, I have no idea. It was very quiet & smooth in operation.
Thanks.
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Re: Flywheels 101 - Single mass/dual mass - what's the diff? (froggy47)
froggy,
The single mass is loud because it doesn't damp out the irregular power pulses from the engine the way the DM does (think of a harmonic damper).
The ZF is designed in such a way that it is noisy when it's idling in neutral and "hooked up" (clutch engaged) to the engine. The firing impulses from the engine make the gears in the ZF rattle. The DM quells these impulses and reduces the gearbox noise.
Yes, it does make launching a no-brainer, but it hurts acceleration after the initial launch since the engine cannot gain (or lose) revs as quickly.
It's another GM concession to the GT personality of the C4.
Larry
code5coupe
:seeya
The single mass is loud because it doesn't damp out the irregular power pulses from the engine the way the DM does (think of a harmonic damper).
The ZF is designed in such a way that it is noisy when it's idling in neutral and "hooked up" (clutch engaged) to the engine. The firing impulses from the engine make the gears in the ZF rattle. The DM quells these impulses and reduces the gearbox noise.
Yes, it does make launching a no-brainer, but it hurts acceleration after the initial launch since the engine cannot gain (or lose) revs as quickly.
It's another GM concession to the GT personality of the C4.
Larry
code5coupe
:seeya
Melting Slicks
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From: Lockport NY
Re: Flywheels 101 - Single mass/dual mass - what's the diff? (zrracer)
the alum single mass flywheel weighs about 12-13 lbs...
The cheap way to get a new flywheel is to use a Camaro flywheel machined down .090" and use the Vette friction plate with the Camaro pressure plate assembly.
There are pics, part numbers, detailed instructions, and success stories in the Archives...(hint: Search!)... :D
