> do they make a lighter flywheel? What about Aluminum?
Fidanza offers an alloy flywheel (with a replaceable steel insert for the
friction surface).
I've been running one for perhaps 15 years now; and I like the overall
effect. Makes the car much more nimble at low speeds (mostly in 1st gear).
However, it did have a very definite effect (for me) on launching the car
(initial acceleration from a standstill); behind two different engines. Not
hard to cope with, but even after all these years I still have to think
about it to avoid killing the engine. And I still occasionally do kill it,
usually when I'm just puttering around and thinking about something else.
Also, it is deliberately a very tight fit on the end of the crankshaft. You
can use the bolts to pull it into place (tightening each bolt a fraction of
a turn at a time, in a criss-cross pattern), but I had to heat the flywheel
(with a propane torch) to get it off.
Joe A. had some lightweight steel flywheels made, but I think he sold them
all and has no plans to make more.
There are instructions in the "Competition Preparation" manual for how to
lighten a stock flywheel. Any decent machine shop should be able to do the
work (but I assume will insist you sign a waiver so they can't be
responsible if the resulting unit breaks in operation).
IIRC, the post-50K flywheel is somewhat lighter than the earlier one. I
don't know how the TR4A flywheel compares to either of the early ones, but
it might be slightly lighter still. The 4A clutch is lighter (I'm also
using a 4A clutch).
It's worth noting, perhaps, that weight distribution is important too; what
we really want to minimize is rotational inertia. So weight near the rim
has much more effect than weight near the center.
You also might want to think about what happens if, for example, you miss a
shift and the flywheel breaks from centrifugal force. Serious racers
install extra shielding to (hopefully) protect them if the worst happens.
-- Randall
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