Stock or Lightweight flywheel

So . . . I got this M42 and I have this turbo (rather small turbo TD05-12B). Should I stay with the dual mass stocker (~30lbs) or step up to a lightweight flywheel (14.5lbs)? What say ye?

For street use the stock flywheel will be easier to drive. You'll lose a little acceleration, but that extra mass sure does make pulling off the lights easier.

Other than that I have nothing useful.

I have a 9lb. flywheel on the Celica. I expected it to be a bugger to drive, but surprisingly, it's not. Works just fine. And you can really feel the difference. That's the only experience I have with a light flywheel, so it may be different from car to car. But I really like mine!

I've never found I needed more flywheel. It will take an hour and you'll be used to it and never look back.

I put a 8 or 9 lbs flywheel on my awd dsm, no regrets about it. Seems like a reasonable thing to do anytime I am doing a clutch on a car.

I am so silly, I used a series 4 TII rotating assembly in my FD (it's what I had laying around), so my flywheel actually got heavier...

I had a 7 lb flywheel on both my CRXs and loved every minute of it. I agree with the general sentiment that it's not that bad on the street once you get used to it and it really livens the engine up. Also, really makes fast shifting much easier on the drivetrain.

30 pounds is WAY overkill for a flywheel. BMW does build them heavy. You could lose have that weight and inertia and never notice a loss in driveability

I drive an M50 with a lightened flywheel. It's soooo much better when it come to driving the car, downshifts are truly possible and it really wakes the car up. Yes it's harder to drive in traffic and takes a bit more care when engaging the clutch, but if you ever exercise the car it's well worth it, downshifts are worlds better. Get a single mass and have it lightened, if you are good with a clutch you will love it; if you can't truly drive a stick you will hate it.

Every time my car is valet parked, I have to tell it's a really light flywheel or they stall the car.

The claims about the benefits of a heavy flywheel on the street are vastly overblown. Usually crowed by those who have never run a light flywheel on the street. Those who do run light flywheels on the street find hardly any problems with it.

agreed. I think you might stall it once or twice as you get used to it.. but after a week, will never notice it again

Well it's unanimous...I have 7-8-pounders on both my cars and won't go heaver'n that. Totally worth it.

I swapped out a 40 some lb dual mass to a 13 lb single mass on a street car.

Really no driveability issues, honestly probably not noticeable at starting from a stop, don't have to rev or slip the clutch at all.

On the nvh front, swapping from a heavy dull mass to a lw single mass picked up lots of noise. Noisy when lugging or idling in neutral.

I swapped out my dual mass (97 318ti) for a UUC unit about 2 years ago. The only issue is noise. Rattling when idling in neutral when hot and deceleration noise when letting off the gas over about 65.

I swapped in a 9lb flywheel in the Elantra. I hated my life for 32k miles. It warped and started chattering around the 19k mile mark and was a real bitch constantly. Best thing I ever did was swap back to the stocker (24lb).

went from a 23lb to a 9lb on my ford probe GT and loved it, easy to figure out for street driving, im sure i stalled a lil more often but not enough to sway me from getting another one for my speed6 when the time comes.

Bobzilla wrote: I swapped in a 9lb flywheel in the Elantra. I hated my life for 32k miles. It warped and started chattering around the 19k mile mark and was a real bitch constantly. Best thing I ever did was swap back to the stocker (24lb).

Was it a cheap ebay one? If so, you get what you pay for. Also, I don't think I'd personally go with an aluminum one if I could get a slightly heavier steel version.

I put a lightened flywheel in a Saab turbo and found that it increased lag just a bit. I think that, upon revving up, the engine generates more exhaust energy by having to push against the greater mass of the stock flywheel. Downshifting is more fun, though...

a few years ago I was warned before I drove a buddies miata with a lightweight flywheel.....and I didnt even notice it....by that I mean I didnt have any issues taking off from a stop, or stalling the car. felt nice to me.

another friend with a 350z recently had his transmission replaced under warranty, had the dealer install a new clutch and lightweight flywheel at the time, he loves it, he was so glad he didnt just get replacement stock parts again.

when it comes time to do the clutch in my car ill be getting a lightweight flywheel too methinks.

failboat wrote: ...another friend with a 350z recently had his transmission replaced under warranty, had the dealer install a new clutch and lightweight flywheel at the time...

This brings to mind the 370Z and its "auto-blip" feature. I wonder how this and other "automanuals" will cope with lighter flywheels than they were programmed for. I suppose this is something else that will be addressed with a reflash. Or perhaps they're more closed-loop than that and will simply adapt to the quicker response.

HiTempguy wrote:

Bobzilla wrote: I swapped in a 9lb flywheel in the Elantra. I hated my life for 32k miles. It warped and started chattering around the 19k mile mark and was a real bitch constantly. Best thing I ever did was swap back to the stocker (24lb).

Was it a cheap ebay one? If so, you get what you pay for. Also, I don't think I'd personally go with an aluminum one if I could get a slightly heavier steel version.

To be honest I don't even remember the brand it's been too long. I think the thing that annoyed me more than all the issues I had with them was the fact that I lost fuel mileage (~1-2mpg average) and it was .2 slower in the quarter mile. So basically, I had to deal with a lousy clutch feel and got no benefits from the lightweight flywheel.

With that said, the Elantra uses the retarded pull-type clutch. Clutch "feel" is subjective and it sucks everywhere. But at least with the stock flywheel I don't have to worry about keeping higher revs to launch and the chattering in traffic.

this winter when I redo my 318ti.. a lightened flywheel and heavier clutch are in the cards.

has anyone done a light weight flywheel in a ls1 car (camaro, TA, corvette, gto). i want to throw one in my miata but i don't now if it's worth the cash??

Do it. The engine will rev better, and there is really no penalty on the street, other than a possibly rattly gearbox since a lighter flywheel won't dampen the power pulses as much.

BMW saddled the M42 with a rediculously heavy flywheel, lazy tune and restrictive exhaust. Otherwise, it would have been as quick as the 325s that year.

Also, you can go even lighter than 14.5.

A competent machine shop should be able to machine an M20 flywheel into the 11-12lb range, and then you get a beefier clutch as well.

Although, I don't know how much more an M20 clutch weighs compared to an M42.

HiTempguy wrote: Was it a cheap ebay one? If so, you get what you pay for. Also, I don't think I'd personally go with an aluminum one if I could get a slightly heavier steel version.

My Fidanza is aluminum with a steel insert.