Dual Mass vs. Single Mass Flywheels, Advantages/Disadvantages??????????

[alnukem]

I've been driving my 90 LPE 475 Package car for 5 years now. , now, for the last few days I've been driving a couple of cars with Cams & Single Mass Flywheels........Don't know if I like it. What are the Advantages/Disadvantages of each. Are there limitations on the dual mass & running cams?

[KILLSHOTS]

The heavy dual mass was used to enhance balance and quiet the rattle that's inherent in the ZF6, which is basically a bulletproof truck transmission adapted to work in our cars. If you remove it and move to a lighter single mass, the advantage is that the car will rev much more quickly and will basically mimic an increase in HP. The disadvantage is that the transmission will most likely sound like it's about to fall out of the car. It won't; it will just sound that way. Not ALWAYS...some guys manage to get theirs balanced pretty well and I hear that increasing the idle speed helps somewhat. But my understanding is that MOST ZF6s with lighter single mass flywheels rattle like hell.

[efnfast]

Originally Posted by alnukem

I've been driving my 90 LPE 475 Package car for 5 years now. , now, for the last few days I've been driving a couple of cars with Cams & Single Mass Flywheels........Don't know if I like it. What are the Advantages/Disadvantages of each. Are there limitations on the dual mass & running cams?

No experiance, but lots of reading.
Single mass is lighter = better acceleration.
Dual mass quiets the gear rattle in the tranny. Rumor has it this rattle does no damage, but at idle, sounds like a bucket of bolts.
I'm on the fence on going to a push throw out, and single mass flywheel.

[Demps]

Jerry has an intermediate solution with a heavier-than-Fidanza single mass. If/when I ever change again it will be with one of Jerrysgaskets products.

HPDE car loves the light Fidanza.

Getting off of the line at the strip is "tricky" with the light Fidanza. Street starting and stopping isn't really fun...plus the rattle. BUT, ah, the quick revs.

To me, the Fidanza was a great mod. Now, I think Jerry has the ultimate solution.
Ted

[Paul Workman]

I have the 13# Fidanza with essentially stock cams, NO secondaries, with some custom phasing. The idle was run up to 850, and with the new Accel injectors, it is hardly noticeable.

See what you think...

http://www.youtube.com/watch?v=y1YFa8ruh8A

13# aluminum Fidanza:

It is a little trickier to launch at the drag strip, whereas the dual mass stores sooo much energy it is easier to launch, and smoother between gears (does more damping)
inertia dyno indicates the equiv. of approx 15 rwhp when comparing results. (However, the effective rwhp might be significantly higher than that due to the fact the 15 hp value is the effect in 4th gear. The equiv. may be significantly higher than 15 in low gears where the rate of rotational acceleration speed is significantly higher! Just sayin.)

The dual mass:

the dual mass is 46# (vs. 13# for the Fidanza) and makes for a smooth shifting between gears
little or no transmission rattle with stock cams, and much reduced rattle with big cams.

The best of both worlds might be a steel single mass weighing in at around 22-25#. That might be a compromise, especially for LT5s with cams with aggressive phasing.

With good injectors, plugs, and idle at about 850 on a stock cam motor, I don't think there is much to complain about. I like the extra seat of the pants snap, especially in the lower gears!

Your mileage may vary!

[A26B]

Originally Posted by Paul Workman

.........The best of both worlds might be a steel single mass weighing in at around 22-25#. That might be a compromise, especially for LT5s with cams with aggressive phasing..........!

Paul,

I had 2 different, custom weight ALUMINUM billet flywheels made, 18lb & 22lb, to cover the spread between the uber-light 13# & the uber-heavy, stock dual mass. Now, energy conservation can be matched to gearing and desired purpose, i.e. street driving, drag, autocross and road course.

Both new flywheels are dimensionally identical to the stock dual mass to preserve the same clutch geometry with the stock, pull-release clutch. Both flywheels can also benefit from the installation of a push-release clutch with the RAM style Hydraulic Release Bearing.

[alnukem]

Originally Posted by A26B

Paul,

I had 2 different, custom weight ALUMINUM billet flywheels made, 18lb & 22lb, to cover the spread between the uber-light 13# & the uber-heavy, stock dual mass. Now, energy conservation can be matched to gearing and desired purpose, i.e. street driving, drag, autocross and road course.

Both new flywheels are dimensionally identical to the stock dual mass to preserve the same clutch geometry with the stock, pull-release clutch. Both flywheels can also benefit from the installation of a push-release clutch with the RAM style Hydraulic Release Bearing.

Sounds good.....have you had any seat time behind them yet?

P.S. Jerry, thanks for your contributions to the LT5 world & helping to keep our cars running!

[tf95ZR1]

What about us top end (Mile) guys?
I have heard a heavier flywheel has
more momentum/inertia available at
high RPM that acts like more torque.

What would be the difference between a
single mass & dual mass of the same weight?
I think dual mass just dampens the vibration more?

[WB9MCW]

"But my understanding is that MOST ZF6s with lighter single mass flywheels rattle like hell."

I have the F 13# and it does rattle a lot at low RPM in 1st and 2nd when you are lugging the motor.

At a stop as well but only when the clutch is not depressed in.

With my ceramic clutch the combo is great IMO and worth the PITA noise.

I kept my DM so I could always convert back if I wanted to.

Along with my secret supplier ECM chip I get some extra spank from the LT-5.

All else is stock on my Z.

I got my set up from Carolina Clutch but this was long b4 Jerry had his offerings = no doubt I would go with Jerry if I were to do it today.

Someday I may go with headers and an exhaust system for more bang but I figure I am on borrowed time with my stock injectors and vacuum system.

So far the "corn squeeze" has not got to my injectors - I do fire up the motor every 30 days all through the winter(s) and use seafoam as well.

62K now and I put about 500 miles on a season. I am a go fast boat guy first and a fair weather Sunday ZR-1 owner 2nd.






THE FOX RIVER IN MY BACK YARD
READY TO GO AT AN INSTANT

[LGAFF]

With a sprung clutch disc from an LT-1 Camaro no rattle.....I went to a normal LT-5 Disc and rattles with clutch in

Honestly I think the perceived issue of driving with the 13# flywheel is overplayed, I have had no issues at all