Street twin + 8lbs = What flywheel?

Ok guys I have a quick question. I am getting a good deal on a street twin and I need to know which flywheel I should get, steel or aluminum.

I am going with the street twin because I am planning on getting a intercooled procharger in about a year. Need to buy good stuff, and from what I can tell from this board, the street twin is the only way to go.

My car isn't a dailey driver but can be at times. I don't race much, just the occasional red light to red light, maybe 1 trip to the track per year. I mostly just drive it when I want to have a little fun. I am thinking that I may want to go with the aluminum.

What is my best choice?

Thanks guys

I am not sure. When I had the T56 in I used the ST with the Al flywheel. The car was hard to launch at the track, it really wanted to either bog or spin. So for the track, I think the steel flywheel would have helped. OTOH, you don't go to the track much. In that case, the aluminum flywheel is probably the best choice on the general principle that it's good to decrease the rotating mass, special situations aside. I never had a problem accelerating smoothly from a stop on the street. I think if you had a really wild cam with poor low end torque and responsiveness the steel FW would be helpful, otherwise go Al.

Rich Krause

Hey Rich thanks for the reply. How noticable was the aluminum flywheel?:confused:

Could you tell much of a difference?

Thanks

Originally posted by JWBerk94Z
Hey Rich thanks for the reply. How noticable was the aluminum flywheel?:confused:

Could you tell much of a difference?

Thanks

Like I said, when using slicks it seemed to be hard to get the launch right. There was a fine line between too little revs and bogging and too much with lots of wheel spin. On the street, the faster revving was noticible when the clutch was not engaged.

Rich Krause

I have a CenterForce Dual Friction with the Al flywheel and so far it has held 600rwhp...

I think that its because of the Al flywheel...

I recommend it...

I've got a steel ST in my car. I went with the steel to save money. I have not noticed any ill effects from the weight of the flywheel. I went from stock rear, aluminum driveshaft and stock clutch to a 12 bolt, heavy 3" steel Denny's driveshaft and a steel street twin. The car ran the same MPH at the track with both setups (maybe it would have run higher MPH with the aluminum?), but it was virtually impossible to get drag radials to 60 foot well with the heavy clutch. On the street the car drives great. I expected to feel sluggishness with the added rotating mass, but didn't notice anything.

That all being said, if I had the money I'd get the aluminum flywheel for its theoretical advantage. There was a big article on the effect of flywheel weight at the strip and on the dyno a few issues ago in Muscle Mustangs and Fast Fords. It may still be online somewhere.

Rich

Originally posted by rskrause
I am not sure. When I had the T56 in I used the ST with the Al flywheel. The car was hard to launch at the track, it really wanted to either bog or spin. So for the track, I think the steel flywheel would have helped. OTOH, you don't go to the track much. In that case, the aluminum flywheel is probably the best choice on the general principle that it's good to decrease the rotating mass, special situations aside. I never had a problem accelerating smoothly from a stop on the street. I think if you had a really wild cam with poor low end torque and responsiveness the steel FW would be helpful, otherwise go Al.

Rich Krause

My car is very similar with the Steel FW: bog or spin. I think its an Fbody thing. A buddy of mine has a 97 Mustang that has the smoothest clutch I've ever felt. It was incredibly easy to manipulate.

Ryan

street twins are on/off switches. hence they are hard to launch with, unless you have a LOT of traction(7K clutch dump) etc


get the lighter one. the AL street twin is nearly as heavy as a stock clutch assembly.

Wow, I just got a reply from ACA performance as to how much the flywheels weigh. 33lbs steel 15lbs aluminum

How much does the stock flywheel weigh? Man, 15 seems really light.

Thanks for the replies guys, keep 'em coming.

Some weights for you guys:
Stock (well worn) LT1 assembly that I just ran across in my basement:
Everything + hardware: 41lb 11oz
Flywheel: 20lb 5oz
Clutch disk: 4lb 5oz
Pressure plate: 14lb 7oz

Weighed on a different scale (but accurate as far as I remember):
Street twin, aluminum: 38.5lb
Street twin, steel 51lb

I have an aluminum flywheel ST, and have driven a number of others, aluminum and steel.

The problem with them, the reason why they seem so on/off is that they have unsprung hubs to make room for the 2 clutch disks, so there isn’t much to cushion the engagement. That Al flywheel version is much more harsh then the Fe (steel) one, mostly because the higher mass of the heavier assembly dampens things some, making it much more pleasant to drive.

For me the choice is simple. If it’s a street car, driver, street strip car, then go steel. If it’s a road race or drag race only car then go aluminum (yea, I know, traditionally you go with a heavier flywheel for dragracing, but that’s with big gear splits and narrow powerbands, neither is an issue in f-bodies, aluminum will be faster). If you’re debating (well, I do go to the track a lot…), look at it this way, I’m at the track every Friday, and if I were to do it again I’d go steel. You really have to be a patient person to live with the aluminum one in traffic, and yea, the steel one is that much better to drive, it could be mistaken for a stock clutch, no way the aluminum one could be.

WS6 TA, You just made me feel better about going with the steel flywheel I just put in with a new 385, What you said was what I was thinking when I bought it and have had friends that have had aluminum flywheels on the street and have switched to steel.

I use aluminum.. I had it balanced with my clutch.. My car is neutrally balanced...

I would go with Al.. its lighter.

I thought these things came balanced from McCleod?:confused:

I don't mind the clutch being on/off quick. I don't want a lot of clutch chatter if I let out slowly. Is chatter what I am going to get by going al?

Thanks

I had mine rebalanced also - even after knocking off the weight it was not a good zero balance - I would have your flywheel then your whole assembly spun up, even if only for cheap insurance.


Chris

I had my ST balanced, It was so far out they had to add weights to the Flywheel

Originally posted by JWBerk94Z
I thought these things came balanced from McCleod?:confused:


They come supposedly balanced with the stock counterbalance for a stock motor (which is not neutrally balanced). It may or may not be exactly right. It's cheap insurance to have it balanced to match your stock setup.



I don't mind the clutch being on/off quick. I don't want a lot of clutch chatter if I let out slowly. Is chatter what I am going to get by going al?



The steel and the aluminum both chatter when they are new. Since the clutch material is the same I would imagine that both will smooth out with use.