Thread: Flywheels Aluminum vs. Chromoly

As I sat in bed, I thought this exact thing. The application really determines what one would want.

I need to hear this.

So what application would determin if you used an aluminum flywheel vs a Chromoly flywheel.

Last I checked a flywheel did 2 things.

1. Transfers power from engine to transmission
2. helps to start car.

Being that both have ring gears and they start the car we are left with one. If bot the flywheels have the same weight then...........

Ask Clekkie, I have to go to work. Wouldn't your opine be bias since you are a JWT dealer that sells JWT Aluminum flywheels?

to me its really neither here nor there, ppl use both chromoly and aluminum, im not sure the benifit of the aluminum out weighs the benifit of the chromoly meaning, the chromoly needs to be turned after use,l and the aluminum needs a new pad which is probably near the cost of turning thechromoly.

the chromoly is stronger though, how much does the jwt weigh?

IMHO, applications such as heavy track/strip use, or just street use would determine whether you'd want one or the other. Aluminum transfers heat better than chromoly, but is more prone to warping if extreme heat is applied for a longer duration. Take a piping hot piece of aluminum and then grab a heavier metal and hit it, and you'll surely damage the aluminum before the chromoly. Think starter trying to turn the flywheel after a hot lapping session.

I see a ton more aluminum flywheels damaged from this than I do chromoly flywheels.

I call BS on the aluminum is more prone to warping in extreme heat. You are able to have more aluminum mass for the same weight flywheel. Also the inserts are steel taking most of the heat then dissipate it to flywheel. If the flywheel were designed completely flat then yes it would have a warpage issue, but they aren't. They have steps cut in the negate this problem.

If heat were really an issue on a flywheel you can cut heatsink grooves to increase the surface area and increase the dissipation rate... I haven't seen that on any designs. If you think it is an issue get with me and I'll do the flywheel design.

I know of MANY applications where aluminum is used in extreme heat scenarios and many of them I can't discuss. Now I'm not argueing you can't have a poorly designed flywheel that has issues, but I've seen more steel ones fail due to that than anything (making things too thin).

+1 There are no downsides to properly designed aluminum flywheels, unless we are comparing a poorly designed aluminum flywheel vs a well designed steel flywheel (which would be retarded).

^I agree. Aluminum all the way.

Mike K. goes into it a little bit in his recent article: Clutch Tech Part 3, Exotic Clutches, Flywheels and Trouble Shooting

For him the main difference is the sound they make. Aluminum is going to be mostly silent. Chromemolly for the same weight will be thinner and are prone to making noise (he likens the tendency to make noise to a bell).

3. evens out pulses from the engine
4. makes clutching in from a dead stop a little easier, IE the car will not instantly die if you're at the wrong throttle% / rpm