I was really speaking to your mention of a lighter flywheel not effecting a
change like a few hundred pound lighter car. There is a certain amount of
effect though.
Because a heavier flywheel will take more power to accelerate it then a
lighter one, it will take a larger throttle opening to effect the same
change in speed. If the detonation is being induced by what you suggested,
the added compression time and thus added combustion heat caused by a
greater throttle opening at the same speed, the lighter flywheel will lessen
the effect by requiring less throttle opening to maintain roadspeed versus
the heavy flywheel.
James Nazarian
71 B tourer
71 BGT V8
85 Dodge Ram
----- Original Message -----
From: David Breneman <idcb@airborne.com>
To: <MGs@autox.team.net>
Sent: 04 February, 2003 6:11 PM
Subject: Re: Cylinder pressure and predetonation
> james SEZ -
> > On the contrary, a lightened flywheel is one of the cheapest performance
> > improving mods you can make, since the rotational inertia goes up with
the
> > square of speed, there is a whole lot of energy stored in the rotating
mass
> > of a drivetrain. A change of 5 or 10 pounds of flywheel weight has the
> > effect of hundreds of pounds at engine speeds. Just like lighter
wheels/
> > tires shortens braking distance, a lighter rotating mass in the
drivetrain
> > quickens acceleration. The less weight that is spinning the less energy
to
> > dissipate when braking. There is a tradeoff though, acceleration is
both
> > positive and negative, so the lighter the rotating mass of the
drivetrain
> > the quicker it accelerates and the quicker it decelerates (negative
> > acceleration) this means that you will lose more road speed up a hill in
the
> > same gear.
>
> I agree a heavy flywheel loads the engine more when accellerating, but
> once you have reached a stable speed, how does a heavier flywheel
> significantly burden an engine to the point that it will detonate?
>
> --
> David Breneman | "Before there were CDs there were
> Distributed Systems S/W Analyst | records, and before there were
> Airborne Express, Inc. | records, there were 78s."
> david.breneman@airborne.com | --- Seen on eBay
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