What is the cut off for weight to determine wither to use an aluminum of a steel flywheel? My car with me in it and a half tank of gas weighs in at 3926#. I have run both types of flywheels. The difference in ET and MPH with my set up is minimal. My car is mostly street driven. Street manners with the steel wheel seems better. The aluminum wheel weighs in at around 20# . The steel wheels is around 33#'s.

I think it is up to you on which one you like, especially on a street and strip car
I did a bunch of testing on flywheel diameter, clutches and pressure plates on my old 1970 Cuda Hemi 4 speed car, started off with with the stock 1968 170 tooth flywheel with the 11.0 inch clutch( I think weighed 40 lbs. switch to a 140 tooth flywheel with the 11.0 inch clucth which weighed a little less but I can't remember exactly how much now
Next was a 130 tooth steel with a 10.95 clutch Borg and Beck style and later tried a Long Style 10.95 clutch, the last swap was to a 18 to 20 lbs. 130 tooth Aluminum flywheel with one of the 10.95 clutches. The car would spin the tires with all the steel flywheels and bog with the aluminum leaving at WOT on all of them
I fnally weigh the front and rear axle weigts and quit racing it after that, it had 2180 lbs. on the front tires and 1260 lbs. on the rear tires without me in it racing on a 9 inch wide slick : down:

Sounds like you need to listen to Cale Aronson the the Clutch Burners podcast.

https://youtu.be/oLgQMFNkKCE

Lots of good info concerning clutch and flywheel weight.

I think not just race weight but SLR would be a consideration.

. Good info here. Thanks. Probably leave the steel wheel in.

There's a section on flywheel weight in a drag race scenario here... Clutch Tuning Basics

Grant

My Cuda with a 4.10 rear gear and 28.0 tal slicks would bog the motor at WOT on the starting line,
I switch rear gears to 4.89 and went back to spinning the tires so I put some 29x9x15 slick on it and switch the rear gears to 5.13 to make it RPM through the lights
That was back in 1974 to 1976, no internet and I was a learning rookie making mistakes testing and racing at the same time
Once I weighed that cars front and rear weight I took it apart and sold it as a street car and bought back my old 1963 415 HP M.W. car and started winning bracket races and having fun
My message is if it ain't fun, why do it

I was discussing flywheels with a few of the UMTR guys about aluminum flywheels and one of the opinions had my interest. The idea was that even though the inertia is greater with a steel wheel the aluminum wheel recovers RPM quicker between gear changes. I have a new aluminum wheel that I intend to use if I put the old Hays Mark XII plate back in because that 12 bolt adjustable plate is freakin heavy.

Gus

Interesting. Steel gets you moving better, but aluminum recovers between shifts better

Not always. There are ways to make the lighter flywheel combo get you going like a steel wheel.

I don’t argue about it any more because it’s not worth it. I run an aluminum wheel in everything that is going to see some track time.


Of course, if you don’t have a way to APPLY the clutch then the steel wheel is a bandaid to get the car moving. Clutch application is critical.

Can you point us to the thread where you did agrue it ?

I've help other stick shift racers. years ago, using a early A body 3.09 first gear tranny in a later A body case, taught us that the starting line ratio and. 3rd to 4 th. gear RPM drop can make a lot of difference in a drag only car, especially SB cars
5.57 rear gear with a 3.09 1st gear in a 3000 lb. SB stick shift drag car keeps you pretty busy ( ) the first 300 to 500 ft. depending on the rear tire size

The part about launch rpm vs trap rpm is very interesting. I may reconsider my aluminum wheel.

Yup. At least reconsider it.