Steel or aluminum?

[ws6drbob]

I am going to replace my flywheel within the next few weeks and was wondering what the advantages/disadvantages were between aluminum or steel. I remember reading in a thread a few months back that steel was better because or the inertia it creates and that an aluminum flywheel can cause some small loss of power at certain RPM's. Anybody that can explain to me what the pro's and cons are for both? I was kinda leanin towards the SLP billet steel.

Thanks

[Injuneer]

Its sort of a mixed bag... a steel flywheel obviously weighs more, so it takes more work (= HP) to accelerate it to high RPM. You will have less HP at the rear wheels with a steel flywheel. On the other hand, it does "store" energy when you bring it up to high speed. Sitting on the starting line, with the engine at 5,000rpm stores a lot of energy in the flywheel, and dumping the clutch transfers some of that energy to the rear wheels. With an aluminum flywheel, you might even notice it is harder to get the car started smoothly from a standstill with a manual tranny. I think the road race and Auto-X people like the aluminum flywheel. Drag racers like the steel.

[Jeff_in_Atl]

Do the aluminum flywheels have a steel teeth for the starter?

[Injuneer]

Yes, there is a steel ring gear with the teeth for the starter.

[dochidalgo]

Another questions then...
The stock flywheel is steel or aluminium?
Which one is better for a car with auto tranny?
Thanks for your reply
Dochidalgo

[Jeff_in_Atl]

Another questions then...
The stock flywheel is steel or aluminium?
Which one is better for a car with auto tranny?
Thanks for your reply
Dochidalgo

Stock flywheel is steel.
Automatics don't have flywheels. They have flex plates.

[DeWynter]

Another questions then...
The stock flywheel is steel or aluminium?
Which one is better for a car with auto tranny?
Thanks for your reply
Dochidalgo

on a auto I doubt you would gain much of anything from going to an aluminium flex plate. The weight difference would be minimal as the flex plate would have to be quite beefy to take the load.

[Jeff_in_Atl]

I know a guy with a stock 92 Chevy 1500 Silverado that his stock steel flex plate ripped in half through 2 of the mounting holes. I think it was a factory defective plate but they do take all of the load of the engine. I don't think an aluminum plate would last 1000 miles at the same thickness. Especially if you had sticky tires. It would have to get a lot thicker. I'm not sure if there is room for it or not. I have never seen an aluminum flexplate. That doesn't mean they don't exist though.

[DeWynter]

I broke my flex plate on my 68 GMC truck in two spots between the big holes cut in the plate. Now that was a hell of a racket!

[raroZ28]

alum., the only way to go if you have the funds! I think the fidanza has a replaceable surface, so you don't have to get a new one everytime you do your clutch.

[fastTa]

Like Fred said, a steel flywheel will store more inertial energy and will thus be more favorable for drag racing (specifically launching). An aluminum flywheel allows the motor to rev much more quickly and allows more power to the wheels. This makes the aluminum flywheel more favorable for road race and Auto-Xing.

I have never heard of a aluminum flexplate. Like Jeff mentioned, to use an aluminum flexplate it would take a significantly thicker flexplate to withstand the force applied to the flexplate/converter bolts. They do make carbon fiber and titanium flexplates but they are pricey and a non-defective steel flexplate will usually do the job on a street/strip vehicle.

[Injuneer]

Speaking of flex-plates (and possible hijacking the thread), has anyone looked at/bought the new Meziere "billet" flex plate? Any idea what it costs? Any idea what advantage it would hold over your basic $89 SFI-rated plate, which seem to hold up to 1,500HP or so?

[fastTa]

I should have been a little more specific. I've never heard of a cast aluminum flexplate. I would imagine that the billet aluminum flexplates would work well. They can also be coupled with custom inertia rings to suit the specific application.

I've heard that the billet Meziere flexplate is good. But I have also heard that the billet aluminum flexplate made by Reactor Products is much better.

[dochidalgo]

Gee, no doubt about it....I do learn a new issues each day.....I did not know my car's auto tranny has flex plates instead flywheels...

Thanks guys...you're my teachers!!!

Dochidalgo

[NJSPEEDER]

personal opinion about aluminum flywheels.
i believe that the gain down track is more than worth any possible sacrifice off the line. although the intial hit is a little softer, you can compensate by adjusting your launch rpm or clutch release to couter act at least 90% of teh difference. the reduction in mass will show itself the most once you get into high gear, so don't expect a huge drop in your 1/8th times.
i know many people over teh years that have played with light weight fly's have stock gears, i think this is a big no-no. although you can adjust to compensate for the way the car will launch, the lack of torque multiplication from the lame ass stock gears gm gave us all makes it difficult at best to find the correct way to compensate. less multiplication = more sensitive to inconsistance launches.


later
tim