Aluminum flywheels are the hot ticket for road racers and wannabe road racers like me. The idea is to reduce the reciprocating mass so the engine can rev quicker. Keep in mind, it's not going to rev any higher or with any more power, it's just going to do it a lot faster. In other words, aluminum flywheels let you get to the peak of your power curve a lot quicker.
None of this is new. What's new is I wanted to see if a Corvette with an aluminum flywheel could be driven on the street. I've been told for years that if I installed one I could expect improved times at the track, but I would barely be able to move away from the corner stop sign.
My transmission recently had to come out in order to repair the OD, so I figured this was as good a time as any to find out if I could drive a Corvette with a lightweight flywheel on the street. The guys at Fidanza said this wouldn't be a problem. Then, a friend told me an aluminum flywheel wouldn't be a problem if I just spent a little while learning how to drive all over again. That's encouraging.
Now this is a serious clutch....
Now this is a serious clutch. This clutch does not slip. Even better, the hotter it gets the better it grips. The only downside is a little shudder when I leave the pits or a stop sign. This Zoom clutch will hold a lot more horsepower than I'm ever going to have-at least for the next couple of years.
After about 30 seconds of thought, I decided to not only replace the flywheel, but the clutch and pressure plate as well. Fidanza hooked me up with the guys atZoom Clutches, which sells the whole package.
What Does It Really Do?How does this lightweight flywheel work? More importantly, what's it going to do for me? Remember, it doesn't contribute a thing to power output, but it makes you faster. How can that be?
If we measure the power output of an engine with the standard GM flywheel and again with a lightweight aluminum flywheel, there won't be a change in power. This makes it appear the aluminum flywheel did nothing and was a total waste of cash. That's totally wrong. It's money well spent.
Remember, the dyno shows maximum power at constant revolutions. It doesn't demonstrate what happens to an engine's power output in real-life situations, such as vehicle acceleration.
This is my new flywheel. The...
This is my new flywheel. The best part is, I don't have to buy a whole new flywheel if I tear up the face. The metallic center is replaceable: just remove the flywheel, and Fidanza will install a new face.
When you accelerate, the engine not only has to move the total mass of the car, but also the internal components of the engine, which requires a considerable amount of power. Anything you can do to lighten these internal components means more power is available to accelerate the car. When you lighten the mass of the flywheel, less power is required to accelerate this mass, so more power is available to move the car down the track.
Removing a few pounds from the flywheel can make a noticeable difference to a 3,000-pound car's acceleration.
Here are the basics for an aluminum flywheel. There's no horsepower gain at all. You're going to get faster crankshaft acceleration, which in turn means faster acceleration on the track. This means horsepower is deployed faster, even though there is no more peak power. The bottom line-it's a hell of a lot more fun. I'm shifting into the next gear almost 20 yards sooner than I used to with the old steel flywheel.
Here's the old flywheel and...
Here's the old flywheel and clutch. Amazingly, the much smaller Zoom clutch has a whole lot more grip.
In turn, this means I'm going faster down the track as I approach the next corner. Racers call this carrying more speed into the corner. That means you can pass more cars, which is a good thing.
The aluminum flywheel is a good example of using a specialized part for a very specific reason. If all you do is drive on the street, the standard heavy flywheel may work just fine. If, on the other hand, you run a number of track day events, this may be the best thing you can do for your Corvette.
The good news is, my '85 really isn't that much different to drive on the street. I get a little shudder when I pull away from the stoplights around town, but it's nothing I can't manage. Considering what I gained on the track, stalling at a few stoplights is no big deal.