A heavy flywheel has more inertia and it makes it easier to get a heavy car moving from a dead stop. A lighter flywheel will allow the engine to spin up faster and free up more power once the car is moving. It is easier to launch with the heavy flywheel and after that it robs power. What we have found racing the Z is you can launch at a higher RPM and slip slightly more and achieve the same 60 foots with the lighter flywheel as with the heavy flywheel.....Once launched the car goes faster with the lighter flywheel. So yes a light flywheel makes it easier to launch the car, but a skilled driver can go faster with a light flywheel when they learn how to compensate for the lighter flywheel off the line.
