I had posted up in someones for sale thread where maybe I shouldn't have. Perhaps I was sticking my nose where it didn't belong. He has a flywheel for sale and stated it was only 9 pounds, I figured he just did not weigh it right and perhaps was mistaken? Rimco will not lighten a flywheel lower than 12 pounds anymore, there must be a reason. Back in the 80's when I built my little spinner motor they lightened one to 11 pounds for me and the engine would rev super fast, it sounded like a motorcycle and I loved it, however, I had problems with the front fan spinning off the front of the crank as you could not lighten it and it could not keep up. It eventually ruined the crank and had to be replaced. So my question is, what is the lightest flywheel weight that anyone is running here without any problems?

brando has a 'windowed' flywheel. think gutted and a ring gear just left.....
his must weigh 8 lbs.....


but it dont run yet

you are saying it spun soo fast it sheared the fan bolts? what grade bolts?
how did it ruin the crank? twysting/torque? snap in half?

The keyway gave also, I used the stock bolt that came with the fan the first time, but after it came off the first time, I went and picked up new ones that were grade 8 from Hub auto, they were even the allen head with lock washers. It did it about 4 or 5 times before I could no longer use the crank. It was easy to find when it happened, my alternator light came on and it left a nice trail of oil behind me since the front seal is open when the hub comes off.

I find it hard to believe that a lightened flywheel would do that.

It seems that maybe the thrust was not right, and the crank could move back and forth to much..

Not sure.

Rich

Or maybe the taper on the crank didn't match the taper in the fan hub.

12 lbs. The acceleration and deceleration are great for my kind of driving fun.

I just switched to a 13lb for my 1.7 =
WEVO makes a 5 lb flywheel for the 915
Patrick Motorsports advertises 9 lb flywheels for the 901, race only they say

for a good reason. it would be a pain in the butt to drive if the car was your daily driver ...

you'd be tired of your commute pretty quick!
Andy

Scott,

Like I said in the classified thread, we've run a flywheel just like this for two years. Car is AX and DE only. No problems. Nice to see that Patrick MS sells a 9 pounder also.

No problems here from your concern, As my grandmother used to say: "If I sell it I won't get rich and if I don't I won"t go to the poor house."

All good.

Fred

My flywheel with clutch and pressure plate came in at about 18lbs i think. I don't plan on stomping the pedal too much. If I shear some bolts I might have some dowel pins installed.

If you find someone who can do it, I'm sure they'll make a piece of paper as your flywheel.

hmm...

I won a lightened 9.5 lbs flywheel at last years' MUSR. It is currently on my carbed 1.8L. The car has suffered NO ill effects from this. I drive it daily (almost) in traffic and have no issues with stalling or rpms running off to quick.

The best way I can described the improvement is that the car just feels lighter on acceleration (duh....right?). I know that sound obvious, but the difference was HUGE. It reminds me of when I empty the car for an a/x (no spare, etc).

just my 0.2

I've had the 13 lb flywheel in there for 2 weeks, drove to work with it in stop and go CA commute for 3 days, and just completed 2 days of PCA AX totalling over 18 runs. I could go lighter! Maybe more HP makes the light flywheel too sketchy, but I am hooked on the improved throttle response I got at -4lbs and would almost be willing to drop the engine all over again this weekend if I was offered one at 9 lbs.

youd think there is some sort of "lighter" material that could be used to make a fan with (matching o.e.m. structure design specs). phoenolic plastic or ??

All it takes is cubic dollars... Go Carbon Fiber Trouble is the fans weight is only part fo it's forces, it is supposed to be moving air. Assuming the fan weighs nothing (unreasonable) it is still going to act like it weighs quite a bit (much more @ high RPM).

BJH

um..

I see some more weight to lose there Brant... You're slipping...

BJH

Tilton's earlier version was lighter.
but they had a tendency to blow up also...
so this is the version 2, thats stronger and heavier.

Lightest clutch/flywheel I've seen... No starter ring, just enough aluminum around a steel disc area for the aluminum pp to bolt up. Dunno how much it weight but the car had to be push-started...