clutches and flywheels

[ADAM]

so i ordered my new ACT 6 puck race clutch today...it holds a minimum of 342ftlbs torque....since my centerforce which is rated at 267ftlbs is now slipping with the 300ftlbs i am laying down....(ahhh torque..the hammer that will beat down the hondas)

now....what about racing flywheels? are they worth it...who is using one...and where can i get one for my car?

[Shaman]

I put one in my car. The main advantages are less engine braking, more power at high RPMs and quicker spin-up for downshifts.

[ADAM]

so i ordered this nasty little flywheel....it only weighs 11lbs from the 21lb stock one...i am on the quest for total honda destruction next season :) i hope this with the 6puck race clutch won't be too difficult to start off the line :)


http://www.aluminumflywheels.com/flywheels.html

[turboawd]

A lighter flywheel gives you more engine braking because less mass means less inertia means the engine winds down faster when off the throttle. Thats why flywheels are so heavy, to keep inertia up for better driveability.

It does make the engine rev easier, more hp but you need to learn how to launch the car from a stop again.

[Shaman]

Uhm, no. Lighter flywheels mean less braking - why? Because the engine doesn't resist maintaining its RPM or changing RPMs quickly as much. The lighter the rotating mass of the engine, the more true this becomes. Ultimately you have a point, but in practice it's usually the downshift under braking that causes you the problems, because if you mismatch the revs slightly, the flywheel won't let the engine spin up a little (as quickly).

Lighter flywheels help preserve bearings and the like inside the engine, too - so the theory goes. There's slightly less stress on the rotating assembly.

[ctheo]

Because the engine doesn't resist maintaining its RPM or changing RPMs quickly as much.

It doesn't get any clearer than that!

This link explains it rather well...

http://www.inexpro.com/legend_temple/faq/faq08.html#8.4


The flywheel is used to store energy specifically for the purpose of
evening out the the rather lumpy power output from a reciproacting engine.
(Like one push every 180 degrees of crank rotation for a four banger.)

Heavy flywheels require more energy to change their speed. Light
flywheels require less.

Advantages of the heavy flywheel: engine rotation, particularly at
low rpms is smoother. Less gentle or skilled drivers are less likely
to stall from standing start. If one is dumb enough to want to use
the engine for braking (ie downshifting to reduce speed rather than
use the brakes) the heavy flywheel is more effective because it requires
oh so much more energy to increase its angular momentum.

Advantages of the light flywheel: #1, it's lighter. there's no such
thing as good weight. More accurately, there is no such thing as good
mass. Period. #2 because it has less mass, less energy is required to
change its angular momentum (less mass, less angular momentum) thus the
motor will rev freer.

[GR8 Ride]

On the flipside, there *are* potentially some drawbacks to lightweight flywheels.

The mass of the stock flywheel and the crank pulley are designed to counter balance the forces affecting the crankshaft of a reciprocating engine.

On a V8 / V6 / V4, this is less of an issue, as the crankshaft is relatively short. On inline 6 engines however, the flywheel becomes an integral part of balancing the crankshaft. Without harmonic balance, it's possible for the crankshaft to shear.

Generally on an inline 6, the crank pulley and flywheel provide MORE than enough harmonic balance to the crankshaft. So it's not an issue to change one or the other. Changing both is generally not a solid idea though.

A few things to consider with lightweight flywheels. One, you're likely to experience a loss of low end torque. Depending upon your engine, this may be significant. However, a lightweight flywheel will generally more than make up for it in higher RPM operation.

Secondly, most aftermarket lightweight flywheels will tend to rattle a little at idle. A lot of this depends on the design of the original transmission, but it's relatively common. If you don't mind some rattle at idle, the benefits of a lightweight flywheel (particularly at the track) are good.


Pat

[Shaman]

Originally posted by GR8 Ride
A few things to consider with lightweight flywheels. One, you're likely to experience a loss of low end torque.

What if you have more than you can use anyway... a lot of V8 guys are in that boat. That's actually part of why I went in the direction of a lighter flywheel.

Secondly, most aftermarket lightweight flywheels will tend to rattle a little at idle.

Great. More noise.

Had a long nap after that last posting, and I think I'm due for another. I'm surprised I was coherent at all. :)

[ADAM]

hmmm....well some noise at idle is not an issue...since my fuel pump noise will probably drown out any flywheel noise easy.... :)

as far as a loss of low end torque...well i could spare some of that...what i really want is peak power...i have a stump puller right now......

yeah i will probably have to relearn how to launch the car.....a few stalls here and there i am sure are in the future :)