Difference of a light weight flywheel?
 

Hi folks,

Sorry if this is a repeat. My search did not turn up much. I am still very much in the planning stages but I know I will need to buy a new clutch and flywheel when I make my swap, since the 5.0L in my '83 Mustang still has the 10" assembly (and a lot of miles on it now). I've read that in heavy cars, a heavier flywheel is an advantage - less bog off the line, etc. But a V8 Miata is far from a heavy car!! I've also read that on a light car, a heavy flywheel can actually limit acceleration. I'm wondering if anyone has gone from a stock (approx 20#) flywheel to a lightweight, and if so, what difference you noted. For my budget, it would be a big-ticket item, but I also only want to buy this once. I'm wondering if I'll see much difference.

Thanks!
Bryan

The lighter wheel will be easier to get moving. Meaning that the engine will accelerate quicker. Nice deal in race car.

The heavier wheel will be slightly slower to accelerate. But you get smoother operation at low rpm's. Less "bucking".

If you're building a predominantly street car, stick with the stock wheel. If it's a track or autocross car, spend for the lighter one.

I have fidanza alum flywheel and spec clutch in my car. Pedal is not too stiff, doesn't bother me, and it's till pretty easy to get going as light weight car and V8 torque. I was all about trying to keep the nose weight down, and the flywheel is very light in comparison to stock.

All very helpful responses. Thanks!

Fly Wheel Discussion
 

I initially planned on and bought an aluminum fly wheel for many of the reasons mentioned in this post, however, after many discussions with my co-workers and though, i came to the conclusion that it really depends on what you want the car to do, what is it built for?

Yes, reducing the rotational inertia of the drive line will typically lead to faster accelerations but not without a price, or trade-off. The driveability will be sacrificed, that is to say that every time you are not launching to win a race, it will be much rougher than if you had a heaver flywheel. the mass helps to smooth out transmissions and feel less jerk and not be so touchy.

I wanted my car to be a mean street car, yet comfortable and enjoyable to drive, so i sold the aluminum fly wheel and went with steel. You can make up Hp and torque in other ways while preserving the smooth start/gear change transitions.

My build finished in December and has just been out of storage for a month and i have learned that it is important to consider your competition when choosing the powertrain. My build is a naturally aspirated 347 big bore stroker ford, it was DYNO'd at 350 Hp & 350 ft-lbs, It's fast by old technology standards, it's hooks up really well and is fun to drive. I know that i cannot win a race against many modern boosted cars, so is it worth sacrificing driveability to be just a little faster, knowing that i will still fall short against a turbo or super charger?

No issues in mine, good torque and low weight car, the aluminum drives just fine.

Thanks for the additional inputs, folks. I'm thinking that my money is going to go toward aluminum heads and a matching cam, rather than an aluminum flywheel. No trade-off that way. :-)

NP. Mine should be on the road in a month or so, and since I am local, if you want to check it out, just let me know.

Thanks, Jason! Yes, I would love to meet up some time pretty soon. Do you do any autocrossing? Since I now have reliable brakes on the Miata, I hope to get it to e-check and the license bureau over the next couple of days. I'd like to be out with the top down! :-)

I haven't autocrossed in a long time, too hard to give up an entire Sunday, too much else to get done. Of course a lot of that has been working on this project, or my other project cars. Good luck getting it out quickly, glad the weather is changing. Just got my Harley up and running last weekend, and need to change the oil in my 500 this weekend to get it out.