New ACT flywheels.
 

Anyone try these yet? They are incredibly cheap! Chromoly steel with the couter weight included, street light-$349.95 and pro light-$399.95! That's a steal. And such a better design than the new UR flywheel. Any information?

any links?

rotaryperformance.com has them listed.

Can someone explain me what is a flywheels and what does it do?

Please, Im not technical when it comes to mechanical.

Thanks!!!!

Simon.

How would this compare to the Mazdaspeed flywheel that I have heard good things about.

It is a bit lighter and cost nearly less than half the price of the Mazdaspeed unit.

I believe Chromoly is better than aluminum? stronger than aluminum?

Simon,

I'm not sure this includes info on flywheels, but it's a start: http://auto.howstuffworks.com/transmission.htm

The phrase "slight compromise in drivability" kind of worries me since people who have the MS version have said that the drivability was compromised "somewhat". Meaning that they have to pay closer attention to starting in first gear than before. The non pro version seems like the way to go.

All except for someone to install it costing you 6 to 8 hours labor :)

That's what the lift at work is for! :D

Doing a flywheel is a must on our cars. Dont listen to anyone unless you have driven an 8 with it. I did it and wish I did it sooner.

It is absolutely stronger. The problem I have with the UR flywheel however, is not that's it's alluminum, but the design. Where do you want the weight on a flywheel? As close to the inside as possible(in a perfect world of race tracks anyway). The UR flywheel does have the integrated counter balance, and that is really cool. The problem is that it's all the way out on the perimeter of the flywheel. The prolite flywheel however doesn't seem to have much of any metal on the outer edge, aside from that which is needed for the starter ring gear. I could be wrong, but I think the prolite flywheel will rev far quicker than the UR, even if the UR is lighter. This is why I will go with the ACT.

Yeah I'm curious as to what that means as well. I had a Fidanza for my '96 Talon and removed the balance shafts. I noticed if I rev'd it and drove it past 3k rpm and slipped it into neutral real quick, the flywheel couldn't catch the revs and the engine would stall out. Maybe it's something like that?

Does anyone have any dyno or track numbers that show the before/after difference of an aftermarket flywheel on an 8?

I have the MS Flywheel. It takes a little getting used to -- I stalled a couple of times on the first ride out. But since then, no problems.


Actually, you can get the MS Flywheel from Rosenthal Mazda for $522 shipped. Of course, getting it installed is another matter.

Jeff

The ACT is a populoar upgrade on the RX-7. I have plenty of them in stock for $250 if anyone wants one. All you need it the counterweight.

Jason
www.rx8store.com

A flywheel adds rotating weight to the engine. Without a flywheel, several bad things would happen. First, it would be much harder to launch the car - it would stall very easily and you'd have to rev the car and slip the clutch on launch. Second, the revs would fall much quicker between shifts, making it very difficult to get smooth shifting.

It does other very important things as well, like aiding in the dynamic balancing and damping which helps to keep your motor in one piece.

The down side to a flywheel is that it adds rotating weight to the motor, which makes the overall car accelerate slower. Replacing the factory unit with a lighter flywheel makes the car more prone to stalls, but you will generally notice better acceleration, at least in first and second gear. This is a good thing for an '8 given their lack of torque from a stand still

I have one in my Miata and I love it. It was very easy to get used to. I hope to do one in my '8 as well.

Hey guys... wanted to clear one thing up. All RX-7/8 flywheels have a counterweight, including the ACT unit. The counterbalance mass requirement is a fixed amount. The radius at which the weight is placed on the flywheel determines how much actual weight is applied for counterbalancing. The end result has to be the same no matter how you do it. So what this means is weather you put a smaller weight towards the outside of the flywheel (like ours) or a larger one towards the inside (like the ACT and Mazdaspeed unit), the counterbalancing effect is the same. Hope this helps!