Will aluminum flywheel be a disaster?

depends onthe combo, I ran aluminum flywheels on my old LT1 Firehawk and it was night and day better in terms of response and quick shifting. I was also very happy with the aluminum flywheel swap in my 25+ PSI boosted Mitsu Eclipse sleeper.

440's are no slouches on torque and if you have decent compression and the right type of (diaphagm/centrifugal) dual friction clutch it could work well with say a 3.91-4.10 gear (where your total first/pull-away) gear has decent torque multiplication to get you launched. But with a traditional 3 finger (bang-bang) clutch like an OEM mopar I don't think it's a good move at all.

I have had this conversation in the pits at a few UMTR races and some say that an aluminum wheel may lose a little at the hit but it recovers quicker between gears I have a lightened steel unit in my car at only 22# which seems like the best of both worlds.Although my flywheel weighs more than some of the complete assemblies out there from Advanced and Bonifonte custom jobs.
Gus

Kilroy,

Borg & Beck = no centrifugal apply leverage plus the rotating mass is higher than a typical centrifugal clutch/pp set up, I don't think I'd want to bolt a heavy countersprung mass to the aluminum polt holes and try any kind of modulation from a light....A Modern design dual surface friction disc like South Bend would be my choice for something easy to shift fast with high holding force and lighter mass. Higher rotating mass counteracts the reason for going to a light flywheel in the first place.

I haven't switched back to a 4 speed for my 517 yet because I haven't researched enough of the options for clutches, I would consider a light flywheel because I have pretty unholy torque but to my mind you have to have some initial 'give' like a diaphagm clutch would have before the bite.

You have to be careful with centrifugal assists as well (longs can fall into this category too).....during part throttle shifting you could see some slippage because you're not generating ebnough rotating inertia to engage the counterweights.....to me it'd be a tough balancing act to get a 'just right' street strip clutch but there are experts that know a lot more about this than I do....i'm just an expert at shifting


I know what I'm looking for I just don't know if I can get it...but when I'm ready I'll talk to the south bend boyz first!

I am running a all aluminum fly wheel from ram with the steel insert
and the engine is a street /strip 493 Rb with hemi 8 bolt crank ,and 10.8 compression . solid roller cam,Indy Sr heads.
the trans is 18 spline hemi 4 speed in a stock heavy 69 dodge charger
with 4:10 detroit locker
This is been my experiance First the car launches hard on the street with drag radials , never had the car together with a heavy fly wheel
so i have nothing to compare it to .
the clutch is a dual friction center force works great i love the light pedal feel and shifts so smooth that some time i don't think it got the gear because so quick .
the only thing i feel is at very low speeds less than 2000rpm the car seams to have a pulsing feel to the drive train , i have read that this is a side affect of low speed inertia you are talking about .
But all the other benefits seam good, car revs real quick like a small stock car engine .

I ran a Hayes aluminum/steel insert FW with 3400# 3- finger Direct Connection pressure plate in my '68 Charger 440. It was easy enough to drive with 4.10 gears but required much more care with the left leg. With 3.55's I wouldn't want my driving to be 75% traffic. On my new 'touring' build, I went back to an all steel flywheel, centerforce clutch and a 505" motor. If I was racing any more than infrequently, I'd still be using the aluminum wheel.

Everyone THANKS for the info and the real world experience, They have really helped me decide! I also searched UMTRNorth.com and searched for aluminum flywheel in the clutch section and came up with some good info too!

Later this spring (once it gets warmer here in IA and I can drop the trans in the drive to my neighbor horror, that when its funnest) I will update with my result.


Keep it coming if you have more. Im glad this sparks some interest with people.

On our 70 RR I had the flywheel lightened but it was starting at 40 pounds. I felt the improvement was worth it. I notice you stated that the Hays site recommended steel flywheel or steel insert. Well, that is what you will have with the aluminum flywheel with the steel insert, so you are good there.

What type of disc is the 930 series? Is it sintered iron? I tried to find it on the Hays site but they do not admit it exists as far as I could find.

We have a Tim Hyatt built slipper clutch based upon Mcleod components. It is adjustable with a sintered iron clutch so you tighten it up for the street, loosen it for the track. We run a 4.3 rear in our RR so I do not know just how bad the 3.55 will be. If you have to slip a sintered iron disc on a regular basis due to the 3.55 it will not last long from what I have been told by people more informed than me. Go to UMTRnorth and give Tim Hyatt a call, his phone number is on there. He might be able to set you up for less than you think, even if it is just the disc. You might be able to get a Mcleod disc through him for the cost of the RAM. The Mcleod I believe are considerably thicker so last longer.

Another thought, you have not mentioned what you have for a pressure plate. That is another part of the equation. Wound up for the street our clutch hits hard but the street tires will always slip to save the rest of the drivetrain. What I like about it is that the clutch will be there at the end of the night, it is tough.

UMTRnorth.com is a great resource.

Was your clutch slipping?

RAM stuff is kinda hard to bring up on jeg/summit pages. The 930 is a dual friction type disk with organic/metallic compounds. A hybrid of their 900 series and told them the same story as below. I email RAM tech told them my situation they suggested 900 series and said the 900 would be good for 650 HP using their BB plate which specs like mine. and yes the insert in the aluminum wheel will be the fixer for the steel part of it.

I originally tried a diaphragm clutch (2400#lbs) with a 6 paddle disk. It was very chattery which could be lived but it did not hold the power in any gear (even high and not completely even in low), and just to head off speculation yes on both clutches I double and triple check clearancse (disk and t/o bearing) and oil leaks.

Now Im running Hayes BB w/ 2750#lbs static with a 850#lbs @ 6k rpm assists. They supplied an organic disk that has been very tame to say the least. No longer slipping in high or low but when I am really hard on in second or try to heat the tires in a second gear burnout it wont hold then. Otherwise its adequate. This is the reason for the switch