madwolf

What are they?
This is on a street car, Spec stage III and the car will see some road racing.
Thanks.

brain

From all tests I've seen done, the ONLY downside to an aluminum flywheel is that it is not factory, and therefore costs money. The only other issue is launching. A heavier steel flywheel will make low rpm launches a bit easier, but if you can get the launch down, the aluminum will outshine the steel everywhere else. I think the gain is worth the effort.

GreenDemon

An aluminum flywheel will make clutch engagement a little trickier. But other people run them, so it must be something you can get used to. Also, aluminum is softer, so I would imagine the clutch disk will eat into it a little faster, that and it's more prone to warpage, so no riding the clutch and be careful who you let drive your car.

Pro Built Automatics

Most aluminum flywheels (if not all) have bronze or steel inserts to eliminate warpage.

unvc92camarors

how low of a weight would you guys reccommend then?
reason i ask is that my stock clutch may not hold up for much longer and i'd consider getting an aluminum

markinkc69z

I would recommend not going to aluminum if you are planning on drag racing a full bodied car. Better 60' times can translate into nearly 1.5 times the improvement in the 1320. An aluminum flywheel on a heavy car can murder your 60'. Finding a launch rpm that doesn't kill the motor and doesn't fry the clutch can be tricky. Driving on the street can be a chore too because the engine rpm drops quicker on the shift and doesn't carry any momentum leading to a kind of bucking feeling until you get good at it. Driving away from a stop requires more effort too due to the lack of inertia. Hey, its just my opinion and I still have an aluminum wheel in my '69 but next time I'm in the bellhousing I'm putting a 30 pounder back in it.
For road racing it might be a viable option.

brain

I agree with mark on the launch aspect of it being a bit more difficult, but as far as driving on the street, I haven't had a single problem mentioned. Even with my cam its as easy to drive as my honda accord. No bucking, or extra effort needed.

markinkc69z

huh, it might just be me.

magnumv8

Ive allways heard that the Alluminum ones are better for road racing and the steel are better for drag racing. I went with the steel one with my Street Twin.

madwolf

Well, I have a steel and an aluminum one coming my way. I'll have to decide when I have all the parts here and ready to put it in.
Thanks for the help guys.

teke184

i don't drag race...and i have a Fidanza alum FW on order.

even if it's trickier to get the shifts down, i think the 1/3 of the weight will really alow the engine to rev up.

if an alum driveshaft (into an LT1) can free up 5-8#s of torque..imagine what a flywheel would do!!

bluecmaro96

so if a billet steel fw weighs 12.5 lbs how much does the aluminum one weigh?

teke184

most of the billet steel fws i've seen are around 25Lbs

my fidanza alum fw weighs in at 13lbs

got it all installed with the new Spec 4 yesterday. put about 10 miles on it so i'm still breaking in the clutch. but pulling out from a stop doesn't seem to be any harder than it was before...mostly due to the touchy low rpms with my 233 cam.

i'll give more info when i break it in

there seems to be a bit more vibration, but i think that is the clutch breaking in.

Heatmaker

I must of got the luck of the draw... my SPEC Billet fly wheel is acutally heavier than my stock flywheel. I mean 3lbs heaver.

teke184

well i've basically broken in the clutch.

the engine revs SCARY fast! a light blip of the throttle and it jumps 2k rpms.

i did pick up a little added high frequency vibration. this could be the clutch also i suppose.
but realize that with the lighter flywheel there is less mass to soak up vibration in the engine (specially with a big cam) and i also have poly motor mounts, trans mount and torque arm mounts. so i could just be feeling the vibration alot more than stock bushings would allow.

i'm happy