Snrub

iTrader: (1)

This just occured to me, tell me what you think; I believe the flywheels may be internally balanced because they have a hunk of metal on the back. You may have seen pictures where there's this ridge on the back that goes almost all of the way around. (see file attachment) If one was to grind it off, I think you might have a balanced flywheel. Ideas/thoughs?

j9fd3s

iTrader: (3)

actually the flywheel needs to be perfectly imbalanced, the rotaries need a counter wieght, to balance out the rotors and mazda casts it into the flywheel

mike

Snrub

iTrader: (1)

Okay let me clairfy. I'm proposing to make it balanced like an aftermarket flywheel by grinding the thing off. Make sense?

banzaitoyota

How are you going to counterwieght it for the rotors?

Snrub

iTrader: (1)

Well you could use the auto tranny counterweight just like with an aftermarket flywheel.

My MAIN concern at this point is: Has what I've said make sense - Is the flywheel balanced exclusively by that ring of metal on the back of the flywheel?

Turbonut

iTrader: (1)

Why grind the flywhel, if you then need to add a counterweight?

Snrub

iTrader: (1)

Turbonut: I've got a scheme cooking, if I benifit from it I'll tell everyone about it then. Actually it doesn't take much to figure out what I'm up to. So at the moment let's not worry about my motivation.

banzaitoyota

If you are planning on making a light flywheel by maching the **** out of a stock flywheel and bolting an auto counterweight to it.

DON"T DON"T DO NOT ATTEMPT!!

Very very Dangerous!. The material of the stock flywheel will not be safe! You stand a VERY strong probability of the flywheel exploding. NO SANCTIONING BODY will allow you to run with one.

Turbonut

iTrader: (1)

It's been a long time since I've seen/heard about a flywheel coming up through the floor!

Snrub

iTrader: (1)

Banzitoyota: I would like to remove that balancing ring if possible to make it evenly balanced, I have no intension of removing anything beyond that. In this way the structure would not be compromised. If anything it would have less stress on it. Still think that's a bad idea?

Regardless of the answer I'd still like to know about that ring of metal.

Thanks.

banzaitoyota

From:
http://www.sakatamotorsport.com/faq.html#7

To a certain degree, lightening the original flywheel at your local machine shop would achieve similar results – in essence, you indeed would be reducing the mass of the flywheel itself and making it lighter. But in doing so, you take BIG risks. For one, the amount of material that needs to be removed to achieve the same weight savings of our unit would be EXTREMELY DANGEROUS and impractical, if not impossible. Secondly, materials OEMs use are not the same type of aircraft grade alloys we use, and there needs to be a considerably greater amount of material on the factory unit to maintain the same strength. We absolutely DO NOT recommend lightening any stock flywheel for the risk of it coming apart at high engine speeds or during severe clutch/drive train engagement. It is not worth taking the chance of the flywheel coming apart at high speed (exploding) and having the ring gear exit the transmission case like a circular saw…cutting everything in its path including your feet! And trust us, this does happen…

Snrub

iTrader: (1)

Alright we're going to have to explain this in full. S4 flywheel 28lbs, S5 flywheel 22lbs. The only difference beyond the wieght is that they are balanced to work with their respective reciprocating assemblies. Now if someone was to take a stock S5 flywheel, grind off the balancing and use a S4 auto counterwieght, they'd have a lightned flywheel that seems to me would be safe. Again, this is assuming the ring of metal is the exclusive balance.

In the above case they are assuming that you are taking a flywheel and cutting holes or grinding it to achieve the results.

Thanks for the continued input.

My Junx

dude, if you remove the built-in counterweight of the stock flywheel, you will still need to add on the same mass in the form of an auto counterweight. the trouble to do this is not worth it. And also you would severely harm the structural integrity of the stock flywheel.

Snrub... if you have an S5 flywheel and you grind off the cast-in counterweight, and add on an S4 counterweight, you will then have the wrong mass counterweight for your engine (if it is an S5, but the correct mass counter weight is it is an S4...but a very dangerous and wreckless method of getting it).

j9fd3s

iTrader: (3)

how are you going to bolt the stock flywheel to the counter wieght? and more importantly why, its still not going to be as light as the heavy racing beat flywheel, and for the time and effort?

mike

Snrub

iTrader: (1)

Are you implying that a S4 flywheel with the internal counterweight removed and a S5 flywheel with the internal counterwieght removed are the same weight? The S4 auto external counterweight is 3-4lbs. Thus the math doesn't add up and the non-counterwieghted flywheel should weigh less.

Why would I harm the structural integrity? The internal counterweight doesn't appear to support anything, it's at the outside. The remaining flywheel would have less load to support when it's spinning.

I have a S4. I want to make the stock S5 flywheel have no internal balance so that it is evenly distributed like an aftermarket flywheel. When you put on an aftermarket flywheel you use an auto counterweight for the year of car, hense why I'd use an S4.

I appreciate all the replies, keep them comming. Discussion is good it brings out the issues.

Snrub

iTrader: (1)

Hmmm...You don't think it will?

RotaryWeaponSE7EN

iTrader: (6)

I tried bolting an aftermarket flywheel w/o a counterweight, yeah right. Just use the counter weight off the auto tranny.

My Junx

ok well it's nice at least to know you have an S4 engine, that helps greatly. See, hearing you starting off with an S5 flywheel seems to imply that you might be pulling it off your car and just grinding off the weight, simply to add it back on in the form of a counterweight....but since this is not the case...I understand. So anyway, in the end you would be looking at a weight savings of about....5 pounds or so, (the difference between a4 and 5 wheel).
About teh integrity of the flywheel...it's just not a good idea to machine any cast metal, a billet can be machined more safely because all teh fibers inside the metal are inline and parallel, as contrasted with a cast metal in which the fibers are entangled and twisted. Look at it like this....you can take a solid steel rod and put it on a lathe to turn it thin in some spots and it will loose some strength but still hold up alright, but if you try to do the same on a piece of cable you would destroy it. Now I know these two cases are VASTLY different, but it gives you a dramatic and easy to see image of the integrity issue.

But hell, I say try it if you really have the drive to do it..more power to ya.

Snrub

iTrader: (1)

My Junx: That's a good point. My thinking is that people grind down the surface of the flywheel to resurface them for a new clutch, etc, so I'd tend to think it can be done from that perspective. If I do go ahead with anything I'll check out that angle first. As for the S4 thing, it wasn't my mistake, check my sig.

j9fd3s and everyone:
I've attached a picture of a 12a flywheel. Is this how mine would look? Note the 4 holes instead of 6 and convex surface.

j9fd3s

iTrader: (3)

here is the stock flywheel:


here is the counter wieght:


see how the counterwieght and lightwieght flywheel are 2 seperate parts? see how the center of the stock flywheel and the center of the counter wieght look the same? how would you attach the two?
your basic assumption is also wrong the, engine is externally balanced, thats why there is a counterweight in the stock flywheel.

mike

Snrub

iTrader: (1)

I wish I'd found that picture in the first place, they've also got rear shots on this page. http://www.mazdatrix.com/faq/flywheel.htm

By basic assumption was not wrong at all, I knew that the engine was externally balanced, the flywheel internally balanced. My problem is I forgot about the bolt holes and didn't realize about the concave part on the back. I was never quiet sure about the stock flywheel working with the auto counterweight due to the combined thickness. Seeing the picture now, I think some grinding could make the auto coutenterweight flat on the side that meets with the flywheel and the stock flywheel ground down by the thickness of the auto counterweight.

The killer is that there are also 2 bolt holes on the front, 4 on the back. Thus it doesn't look like there's a way to get the counterweight on, even if you drilled new holes in there. Oh well.

Thanks again for all the replies.