[s-cars] Re: Installation of clutch: Help? Also: LIghtened Flywheel vs. OEM Dual-mass ...

Djdawson2 at aol.com Djdawson2 at aol.com
Mon Nov 17 00:13:03 EST 2003

[ Picked text/plain from multipart/alternative ]
In a message dated 11/16/03 8:36:25 PM Mountain Standard Time,
Paul.Park at Colorado.EDU writes:

> I can understand why a lightened flywheel will give you better spool up
> times, but I was thinking today about how heavier flywheels are better
> for highway cruisers like ours.

If smooth highway cruiser is all your after, I would agree that a heavier
flywheel helps achieve that goal.

 I was thinking about inertia and > momentum and the like, and how when you
> get off the throttle for a very short amount of time and get back on, the
> engine has not dropped it's RPMs as significantly as it would if it were equipped
> with a lightened
> flywheel.

The RPM won't drop if you don't disengage the clutch....  When you're moving,
the flywheel on your engine is one of many "flywheels" at work.  Think about
your wheels spinning, brake rotors, driveshafts, etc... all are functioning as
flywheels while you are moving.  Just because you lighten the flywheel on the
end of your crank doesn't mean that engine braking will be dramatically
increased.  As a percentage of all the rotating masses on the car, a 16lb decrease
is quite small.

It's hard to explain, but I think Audi placed heavier > flywheels on our car
> so as to allow for better/smoother responsiveness in highway situations. I
> just think that a lightened flywheel would suck if I were to get off the
> throttle for a short amount of time, and have to get back on it to build up the
> revs.

A heavier flywheel is smoother, but less responsive.  In terms of throttle
response, the engine has to "work" to rebuild the stored energy that a flywheel
provides.  To accomplish that work takes time... more time = less responsive.

> Paul
> -confused: Why are lightened flywheels better than stock flywheels for
> our car?

Well, I won't argue that a light flywheel is better for all situations...
But I will tell you that at least it will hold together.  The dual mass flywheel
is a known point of failure on our cars.  I've opted to replace mine, rather
than risk a future failure.
Dave (not a guru) in CO

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