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pdexta
05-16-2012, 02:47 PM
Do any of you guys have experience with a lightweight flywheel? I've always run a stock wheel, I think they're right around 18 pounds. Has anyone upgraded to a lighter one? How light did you go and what were your impressions? Changes to driveability?

It really is amazing how much weight kills our cars, I was consistently 0.25 sec and 2 mph slower through the 1/8th mile with a passenger in the car. I can't help but think dropping 6-10 pounds of rotational mass would make a dramatic difference.

minuteman048
05-16-2012, 02:56 PM
I personally don't but know I a guy from the Orlando group who put in a 10 lb flywheel and is happy with it. I did a lot off reading on this and instead of typing it all in here, I'll just provide the product review links and you can draw your own conclusions:

http://www.miata.net/products/perform/flyinclutch.html

http://www.miata.net/products/perform/indigo.html

http://www.miata.net/products/perform/m ... wheel.html (http://www.miata.net/products/perform/max5_flywheel.html)

http://www.miata.net/products/perform/rbflywheel.html

http://www.miata.net/products/perform/todaflywheel.html

This project is definetly on my to do list the next time I have to pull the transmission again.

2001SE
05-16-2012, 03:09 PM
Do any of you guys have experience with a lightweight flywheel? I've always run a stock wheel, I think they're right around 18 pounds. Has anyone upgraded to a lighter one? How light did you go and what were your impressions? Changes to driveability?

It really is amazing how much weight kills our cars, I was consistently 0.25 sec and 2 mph slower through the 1/8th mile with a passenger in the car. I can't help but think dropping 6-10 pounds of rotational mass would make a dramatic difference.

You might want to PM Flynmx5 (Gearhead) he has some experience with lightweight flywheels. In fact he may have a spare somewhere. Not sure, shoot him a text, that's the best way to get a hold of him. I considered it when I had the trans down doing the clutch last month, but decided I would wait till next time. Just being stock (mostly) DD, I could not justify it. You can PM me for his phone number if that helps.
Good luck.

Tristan75
05-16-2012, 06:49 PM
Hi Pdexta,

If it helps... I did change last year my OEM clutch & flywheel for a Spec 2+ clutch & Spec flywheel.

My impressions with the change were very good and worth the change & investment...

I'm sure, you already know that...

Your revolutions will rise much faster (but do not expect to rise faster of revolutions, when you have a gear in and you are pulling 1000kg because the difference will be minimal)... you don't gain more horsepower, let's say you get them before.

The light steering is great for precision shifting, if you're good doing it... because you can match the rpm in a shorter period of time.

If you think that a lightened flywheel will give you more acceleration, you are partially wrong. A clear example, would be the drag racing cars... because they are very good choosing the right weight that the steering wheel must have, they can gain 4-5kg less drag spinning, but may lose it at the time they rise up a gear and they will lack of inertia.

While it is true that having to move less kg... some power is released in the end to the wheels. It is also true, that you can lose that same benefit when making a gear change or start a slope.

I don't know, if my explanation makes sense :oops:

05-16-2012, 07:52 PM
Damn tourists...

Gazornan
05-16-2012, 08:26 PM
I'm in the minority, I know. I changed to a 10 lb. flywheel aboout 2 years ago, and have regretted it non-stop ever since...

First, a little background: I've been racing cars (motorcycles, trucks, whatever) for most of my life. Most of my cars started out as street cars, and eventually progressed to the point of trailer queens, because I always went way to far. Fast? Yes! Obnoxious, rough, smelly, etc. My last project was a 1984 Rabbit GTi - and it kicked ass at autocross, usually winning the index, and battling for FTD. Seriously fast. It was tough to drive to and from events, got about 12mpg, and reeked of gas. I was running dual Weber carbs.... I sold that car, and bought a Miata. I swore I was going to keep the Miata "street-worthy", so I didn;t buy the stiffest/fastest coil-overs, didn't buy the lightest/loudest exhaust, etc.

When I was replacing my clutch last, I installed a lightweight flywheel. I thought it would make rev-matching better (it does, a little), and make the car a little quicker off the line (it's not). Anyway, my flywheel buzzes so badly you can hear it in videos, and I'm embarrassed driving into parking lost because people think my car is a POS. It's awful. I have many times thought of dropping my trans just to get that %#@*ing thing out.

That's my .02. Maybe you will not have that happen - I understand the buzzing problem is really a crapshoot.

05-16-2012, 10:42 PM
That is sooo true, not just about flywheels but anything high performance in a Miata. I know the hardcore track guys snicker at lesser Miatas but the truth is like you stated. The more "high performance" you go, the less comfortable, the more rattly, the stiffer, the smellier they get.

As for lightweight flywheels, you've probably already read the good and bad so not much to add here except that you can have a compromise. The stock flywheel can be turned to be lighter but not too light or you can simply choose a lightweight but not outrageously light flywheel from Flyin Miata for example.

Dave had a 7lb flywheel but ditched it for a 13lb FM one instead. Much happier now. I think he had noise issues with the super light wheel in his 5-speed.

As for fears that you have to learn all over again how to drive a manual, that is false. It takes 5 minutes to get used to a light flywheel.

As for weight savings. Don't get a light flywheel just to save overall weight of the car. You can definitely some weight, not disputing that but there are other things you can do to lose weight on the car or your body. Either that or add power. If I were obssessed about every unneeded gram of weight in the car, I'd eliminate some other things first.

Jester~
05-16-2012, 10:50 PM
I have a lightweight flywheel in my car too. I'm torn, at first I liked it, then the "chatter" the damn thing made drove me crazy.

Then when I had the engine problem, and had it all apart I stared at the lightweight flywheel and debated if i should put it back in, or go back to stock. I ended up putting it back in, and just made the mental decision that I would rather deal with the noise it made in order to enjoy a little faster revving.

If I had to do it over, I wouldn't have bought it in the first place....but since I already paid the money for it, I'm using it! At least I got it used, but in like new condition....so at least it wasn't full price.

User
05-16-2012, 11:10 PM
Thing to remember is not the total weight of the flywheel but where the weight is located.
In my other hobby people would spend $700+ on aluminum flywheels (I still have 2 of them) only to have them shatter few hours later causing thousands in damage.
I found much better results with an OEM flywheel that a friend up in Tampa would machine down in his shop. Key was to remove mass further away from the center and leaving the hub quite thick.

What does that have to do with the Miata ?
I think there are gains in a lighter flywheel but a more compact clutch and pressure plate (twin plate) might be an even bigger gain.

minuteman048
05-17-2012, 06:04 AM
Great thread! lots of info and experience here.

pdexta
05-17-2012, 09:27 AM
Thanks for the replies, especially those with first hand experience. I think I'm slowly coming to the conclusion that it may just be better to leave it alone until my clutch goes out, or at least until I find a cheap used one. Even then, it sounds like something in the 10-13lb range is probably more reasonable than the super light ones.