About clutch: Aluminum flywheel question

[Christian]

I will probably have to do somework with the clutch of my 1971 LS5. I am wondering about the benefit of an 13.5 pound aluminum flywheel versus the drawbacks.
Anyone have experience with that? What vendor to go with?

 

[ShakeRattleRoll]

A Spinning Question

I would not go with that light flywheel. Stay with the stock weight or right at it. If you intend on replaceing the flywheel then get a good steel Hays or one by Ram would be the way to go.

 

[ernie d]

Just so you know........the really expensive supercars......Aston Martin V12 Vanquish and Ferrari, for example........use aluminum flywheels. They are good at carrying the heat, but most importantly, they reduce the inertia load that the engine must accelerate. Makes the motor more lively!

 

[Robin7TFour]

GREETINGS,yes a lighter flywheel will make the engine rev faster and feel livelier. however, you will have to spin the motor faster to get power. less weight means less bottom torque. also if you're running a manual tranny there will be less compression braking since the engine is running easier,hence brakes better be real good shape.
just a few random thoughts

best wishes to all

ROBIN

 

[drags1998]

Stay with the stock flywheel weight, you will be much happier in the long run. ernie says imports use um, robin says less braking ? Im not sure I agree with either of them!!!!! I wont attack there reasoning, I just dont agree with them.Another case of been-there done-that, I DID NOT LIKE HAVING TO SLIP THE CLUTCH!!!!! TO GET IT MOVING!!!!!!!

 

[AKRAY4PLAY]

aluminum is great for racing, but sucks on the street. that statement is true for tons of parts, but especially this one. if you don't mind low rpm quarks of easy stalling, slipping the clutch get rolling and rough idle, it works well. aluminum wears rapidly, wears uneven and will need resurfacing every 6000 miles if you do a bunch of stop and go city driving.

 

[ShakeRattleRoll]

Okay I did not think we would get this deep into a discussion about clutches lol. Now I have run aluminum flywheels with steel inserts for the wear portion of the flywheel which is okay. I have run these systems from a single disk to the tiny three disc setups. Now these were on Small Blocks which were all turning above 9000 rpm but there is a BIG tradeoff in doing so. One that has been mentioned is that your idle will be erratic as well as your rpm will also have to increase to leave a light or you have to run some deep rear end gears say 4.88 or 5.14 gears. Now these setups are great for tight road courses along with auto cross where the light flywheel will let your engine rev up quicker and will also increase the deceleration of the engine without using the brakes which can save on those often needed brakes when you need them. But to run such a combo on a Big Block Chevy especially for the street would be to say the least a pain. A stock weight flywheel or very close to it maybe a tad lighter is a very good compromise for overall derivability. Years ago for drag racing there were people that had 60 pound flywheels behind there Big Block Chevy for the inertia of the flywheel at the line. Heck I even got to see a few that even though the engine died at the light they would still almost lift a wheel just because of that heavy flywheel turning. You need to figure out exactly what you want to do with the car and how you want it to feel. And talk to the manufacturer on what they would recommend as to which setup to use for your combo. For the street I was very happy with a Hays Flywheel Steel with a Ram 6 puck metallic disc ( Has metallic pads for real grip and also urethane covered springs on the clutch for semi shock retardant) And the pressure plate was also a Borg and Beck Style with roller bearing assist so I could run more pressure on the plate yet still be able to use the clutch with moderate leg pressure. Now this combo might not be for everyone because as I said it pretty much has 0 slip but they did not explode like all the others that I tried and if I did wear the pucks out you could simply take it to a clutch shop and they can just replace the pucks at a very moderate price. But with this combo you are pretty much assured that you will chirp the tires when you leave a light.

 

[Christian]

Thank you guys for all these tips and valuable info. Given that I have mostly a street use of the car, I think I am not going to go for a lighter flywheel although I would enjoy the benefits. Thanks a lot for your help.