Again and again and again, it's pretty much a beatup topic
but i dont mind sharing some notes. Do bear in mind im not
a physicist, so dont mind the basic momentum vs torque vs
power vs whatnottodo vs justbuythedamnthing.
What about aluminium flywheels compared to
TODA chrome-moly steel?
Aluminum has a higher strength to weight ratio than steel,
which is why it is used for the lightest applications, serious
racing only. The main disadvantage of aluminum is that it
has a finite fatigue life. You can only stress aluminum so many
times before it breaks, while steel just keeps going. That is why
you never see aluminum springs, always steel (or titanium or
something else). So aluminum has an increased risk of shattering.
Aluminum also tends to break, whereas steel has more of a tendency
to bend.
Flywheel & torque?
The flywheel doesn't 'create' torque, it stores torque. Removing weight
from the rotating parts of the car allows the engine to provide more
power accelerating the car and not the drive train. The flywheel
provides no torque to the engine so the logic that it is the main
source of torque for the four cylinder is flawed. And the flywheel
does 'create' torque and lots of it on a 4cyl. Torque is,
(in simple words) the weight spinning( crank, flywheel mainly) and
gaing momentum helping to turn your engine. And sure you would
accelerate off the line a little faster with a lighter one but you
would have no top end cause you would have no torque.
Flywheel & horsepower?
A light flywheel won't give you any horsepower. But it will take
less time to get the revs up where the power is at. It increases
the transient response of the engine.
High revving?
All the lightened flywheel will help is revving, you would probably
gain a couple hundred rpms up top, and it'll get there quicker,
however this isn't ideal for daily driving as the engine also loses
revs much quicker, its not too much of a nuisence once you get
used to the way it reacts. Especially with Hondas where all the
power is in high revs, a light flywheels can help alot at the meat
of the powerband.
Inertia?
Inertia is what you have to overcome to get it moving, torque
is what is actually measured when you try to stop or load it.
Fat crank = fat torque?
No, if you were to install a heavier crank, you would NOT get
more torque. Installing a crank with a longer stroke will give you
more torque however.
Worth to buy an aftermarket flywheel?
If you want hp per every cent spent, forget about it.
Machining factory flywheel?
There is limitation in doing this. A good way is to skim a bit
and lose some steel weight on your flywheel and make sure
it has been balanced too. Doing it too much either you will
shatter the flywheel and bust your gearbox or u have a
ninja's shuriken going towards your firewall and you.
