At what point should one use an Aluminum flywheel

As I get more things together for the LeMans, this question comes to mind. Assuming 550hp LQ9 (6.0L truck LS) and T56 is the combo in question, at what point would an aluminum flywheel be a bad idea. I had an S10 beater with an LS1 and T56 that had a Spec aluminum flywheel and it had zero drawbacks with drivability. Of course, it was a 2500-lb truck with 4.10s and a big V8.

I still have the aluminum flywheel and was thinking about it for the LeMans... but its a much heavier vehicle... probably in the 3300 lb range with driver.

Subscribed, as I have been having similar thoughts about the duster at 3400lbs and 425 rwhp. 3.55 gears and a tko600. So the answer you receive should be able to be applied to my situation.

My Supercoupe was in the 3400s or 3500s when the aluminum flywheel went in. I've had zero problems with it.

I had a 24 lb flywheel/clutch setup (flywheel itself was 12 lbs) in my 67 El Camino with a Richmond 5-speed. That was not too bad on the street, but it was noticeable. I would go a bit heavier than that.

I have a Spec aluminum flywheel in a 4300lb crown vic, with 3.55's. I can notice the lightness, but it is fun to drive... I as well had the flywheel so it was used.

Thanks Ross

If you have it, might as well. Not like dropping the trans out of a A body is a big deal if you don't like it.

What's the planned rear end gear?

4.10 rear, but that gets swallowed up very quickly with 2.66:1 first and a 0.50:1 OD.

If you do the maths, 4.10s with a T56 is about equivalent to 3.08s with a 700r4, just to put it in perspective.

Any time you have the engine or trans out is when you should put an aluminum flywheel in. The only exception is if you're in some form of motorsports and your chosen class doesn't allow it.

100% upsides 0% downsides.

Knurled wrote: Any time you have the engine or trans out is when you should put an aluminum flywheel in. The only exception is if you're in some form of motorsports and your chosen class doesn't allow it. 100% upsides 0% downsides.

Well I have been in some that were annoying. Not enough inertia to match the weight of the vehicle and starting from a stop gets annoying. That is my main concern.

Of course I've also been in some that were the opposite; too much inertia to mask low torque, like every 4-cyl toyota truck ever made.

That may be a driver thing. When I drive a manual trans, I accelerate into the clutch engagement, I don't rely on engine inertia to sag into the clutch. So I don't notice a drivability difference. If anything the lightweight flywheel needs less throttle because it takes less effort to accelerate the engine.

And of course, no matter how you engage the clutch, once the clutch is fully engaged, vehicle acceleration WILL be quicker with an aluminum flywheel. It's MORE noticable in an engine with poor low RPM torque because the engine needs to spend less of its oh-too-small abilities in merely accelerating itself.

My RX-7 is a grunt monster everywhere on the tach... except below 2000rpm. Just kicking the fan on can drop the idle speed by 400rpm. But it's still perfectly fine despite the 9lb flywheel.

People claim it kills drivability, but most of them never used one......the ti got a 7lb unit to replace the nearly 40lb dual mass fly and its so much better.

When one wants a 6lb clutch/flywheel combo.

If you had a BMW S52/S54 with a ZF 5 speed this box of sweetness could be yours for $1000. It mounts the button flywheel on an aluminum starter flex plate, with twin disk rally clutches and adapts it to a hydraulic TO bearing.

In reply to G. P. Snorklewacker:

Ugh, I want one of those....my ti has the peasantesque lightweight fly with an m clutch...

In reply to G. P. Snorklewacker:

thas car pron there

It's worth noting that the question is really "at what point should one use a lightweight flywheel". The material is irrelevant.

^^^ true dat