light flywheel with FI

[aphex301]

just began looking into fywheels. I was thinking about getting a light fywheel, say 8.5 lbs. I have i/h/e now- and if money comes in later i might put together a turbo kit and run low psi.

Now is a ~200 dollar investment in a light flywheel a good one? When changing the clutch, is it a good idea to change it since everything is apart?

Ive read that the gain on having a lightflywheel is higher acceleration/low end power. And that the con is top end loss off power. Would any of these pros/cons change with FI?

[superbluecivicsi]

i have the clutchmaster 8.5lbs flywheel and stage 3 clutch on a jrsc @ 9.5 psi.

sucks in traffic, but great acceleration.

[hundahunta]

on a n/a car a lighter flywheel will give you better acceleration but less torque. The flywheel is part of the engine rotating mass more mass means more rotational weight so when you pop your clutch the rotating mass works against you vehicles dead weight to get is moving.. At the sametime since the flywheel is a rotating weight less rotational weight means faster acceleration....

[aphex301]

ok, so from a dead stop, my car with a lighter flywheel would take off slower than my stock flywheel. But if im already moving a lighter flywheel would be an advantage?

[Miataracer]

not exactly... hundahunta is on the right track with the rotational mass, but changing a flywheel does NOT change the actual torque output of the engine. less rotating weight means that the engine and flywheel will be able to accelerate and decelerate faster. as it takes less energy to spin something light than it does to spin something heavy.


**real life situation** you are driving, and are going to downshift. when you press in the clutch the engine will slow down faster with a lightweight clutch than it will with a heavy stock clutch. this makes rev matching more important as if you are slow and allow the engine speed to decrease you end up really giving the synchros in the tranny a hell of a workout.

as far as launch from a stop. there really isnt much reason why a car with a light weight flywheel would launch slower. you will need possibly a bit more rpm and some feathering to launch well but thats about all