team510

Hey, so I was in the process of getting parts to do a clutch job on my ap1. Bought oem everything, and I was going to reuse my fw after I have it resurfaced. My friend who also has a ap1 had a brand new 8lb fidanza aluminum flywheel that he said I can have if I want it. I have done some research and read all about how cromoly should be used and not aluminum when it comes to flywheel. However, I am in the process of building a engine and plan on being done in the next year or so. So worse case scenario I could take the flywheel back out at that time. My question is will the stock pressure plate be okay with a 8lb flywheel, and what exactly goes wrong with aluminum flywheels?

B serious

Yes, the stock plate will be fine with an Al flywheel. The riding surface of the flywheel is steel...the body is Al.

The problem with a 2pc (Al) flywheel is that you're relying on the screws to hold the steel (dissimilar material) friction material in place. You also have an aluminum ring gear to start the car every day :/. As well as using Al as the mounting surface to the crank. So you might get a little indentation or warping at the 92LB-FT torque spec. And Al has a higher chance of splitting or breaking apart. You wouldn't imagine the stresses that your clutch and flywheel are under.

9000RPM is a rotational speed of 150 times per second. You're also using the clutch and flywheel to transfer 240hp to move a 2800lb car.

Chromoly (steel) is just about the perfect flywheel material.

I would keep your stock AP1 flywheel. A 8lb flywheel is going to be annoying as hell to drive around with anyway.

zeroptzero

I'm running the ACT ultra-lite (8.6 lbs) with an oem clutch disc and p.p. setup on my car, it works great IMO. Light flywheels are harder to use with higher force p.p.'s.

Aluminum flywheels have the potential to shatter / self destruct under high shock conditions , in some situations that could be dangerous as flywheels contain a lot of energy as they are spinning. Chances of it happening on an S2000 that is properly driven is low, and Fidanza is a reputable company. We are talking about very rare occurrences and usually on big motor applications, you should be fine using it as you have described. I personally would avoid it as a long term part but since you will be back in there next year you could see how it works and decide if you want to swap it out in a year's time.

MP2k

I've abused a Fidanza flywheel on the s2k and a few other applications. None of them had aluminum ring gears for the starter ring. Never an issue with mounting to the crank. The steel friction insert on one of them stood up to three separate disks being run on it with one of them being a six puck abrasive enough to wear a small groove in it. Yes aluminum has a higher risk of explosion but do you think so many companies would continue to make them if it was that common? I switched mine out for an ACT prolite in search of a lower moment of inertia. Yes the ACT is slightly heavier but the distribution of the weight is centered closer the crank and should be easier to accelerate. In reality there wasn't much difference but the ACT was SFI certified so it wasn't a complete waste. There is no debate about CrMo being a better material. A light flywheel makes the car really come alive and only takes minimal time for a proficient driver to master. It is NOT the light switch everyone makes it out to be. You will get more noise from the drivetrain as the lightweight rotating assembly causes resonance through the transmission and clutch disk springs. Some of the noise can be mitigated by using an unsprung clutch disc. I wouldn't hesitate to use a Fidanza if you can get a good deal on one.

team510

thanks for the input guys, probably going to go ahead and throw in the fidanza flywheel and see how i like it. My biggest concern was that a stock pressure plate would not be a good combo with a 8lb flywheel.

zeroptzero

I think they are easier to drive with an oem pp, so no worries there.