A bad Easter weekend,

[Tool Pants]

A lightweight flywheel does not increase HP. A flywheel does not generate energy.

Throttle response, yes. But have fun in normal street driving.

Or, so I have been told....

[986Jim]

A lightweight flywheel removes rotating mass off the motor. Going from 31lbs to 13 is a huge reduction. The weight the motor no longer has to waste to spin that thing goes directly out in wheel HP. It doens't give additional HP but recovers some lost HP from the drivetrain.

Funny thing about lightened flywheels is they don't carry any inertia. So downshifting to slow the car down is almost pointless and if your one of the people who push the clutch in at 4000rpm while slowing for a stop sign the car will stall as the rpm has too far to fall, too fast with so little weight on the flywheel that the computer can't catch it on its way crashing down and the car stalls.

You can pop out the clutch again to start the car (kinda like bump starting but your already rolling) or you can just gear into 2nd when your coming to a stop and let the car right out almost a stop in gear, this will keep the RPM from crashing down. Really thats what your supposed to do, you shouldn't be pushing in the clutch at 4000rpm and letting it fall as you coast to a set of lights.

[Perfectlap]

I had a Fidanza lightened flywheel on my Miata. After first installing it my reaction was

Completey changed the whole experience. I kicked myself for not doing it sooner until I remembered its a big job that should only be done when the cluthc was replaced. Best bang for the buck from a maintenance job for sure.

But with its greatly reduced weight came ALLOT more noise. I could actually hear it spinning and the car was noisy to begin with! Very visceral, I loved it.
Some people didn't care for all the racket and complained that they felt like they were in a tin can.

Like most mechanical mods I recommed finding soemone with who has the mod already and going for a ride. Otherwise its an expensive roll of the dice. I learned this lesson with suspension mods in a big way.