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balancing.Settled?!....



Snip, snip...

> Two cars, going 70, side by side...  One is 2000lbs, the other is
3000lbs...
> You two both approach a hill...  Neither one of you attempts to
accelerate,
> or to maintain the same speed...  Which one will go further up the hill?

"The one with more potential energy stored. (i.e. the 3000 lb car or the
car with the stock flywheel)

But that energy is not free; I think that's what you're not getting here."
I get it...  My argument was around sustained journeys, not in town races,
therefore...

"You've already converted it from stored energy (gasoline) to stored
energy (flywheel). So yes, it may (will) help you go up a hill
->with no throttle<- but no more so than just stepping on the gas and
burning that same amount of fuel would in a car with a light flywheel. And
I don't know anyone who (on a regular basis) lets off the throttle
completely and coasts "up" hills."
I know, that you know that the up hill part was just an illustration for the
greater inertia...  Umm, quit that...  :)


"With a stock flywheel you're shopping at Costco and with a lightened one
you're buying single items. Every time you stop you have to throw away
everything you've bought. So yes, if you don't stop, shopping at Costco
could save you trips to the store. But those trips don't take any
additional time or effort (the engine is already running when you're
driving) so there is really no benefit. You just waste a lot more."
And of course, that stems back to what the car was built for...  And whether
you were true to its design...  In other words, we agree...  Damn, that is
satisfying to say...

> This is the whole of my argument...  More spun weight carries more
inertia,
> which will, under some circumstances, benefit the driver...  Does that one
> make sense?

"Yes, and I agree with it 100%. Under some circumstances more inertia will
benefit the driver (like driving through a brick wall, or mangling a
pedestrian). But your original argument was that more interia would
increase fuel mileage. That's what I disagree with."
I still have not found where I said this...  If I did, then I really did
step in it...  What I was TRYING to say is the decreasing F/W can decrease
mpg...

"Conservation of energy says you can't create energy out of nowhere."
Agreed...

"Okay, lets try a money analogy. It costs $1 to drive up a hill with a
lightened flywheel, and $2 to drive up a hill with a stock flywheel.

It doesn't matter where the money goes (to charity or to McDonalds)... to
wind drag or friction, you already spent it climbing the hill.

Even if, after cresting the hill, the stock flywheel car can coast twice
as far before coming to a stop.. all you have to do is spend another $1
(well, actually less than that since you're not going 'up' anymore) to go
the same distance in the lightened flywheel car."

Now I am losing you again, methinks...

> "Which brings up one more thing-- the fuel dumped in to the engine is
> determined by the air flow plate position, not the throttle position."
> Actually, it is the other way around...  If you take your foot of the
> throttle at 70mph, and decelerate, there is no fuel entering the engine...
> With your statement above, if that were true, then a lot of air would go
> through/around the throttle butterflies, which it cannot do...  If it
could
> it would not do any good to have a butterfly there at all...

[air flow plate shenanigans snipped]

"Okay, now you are misunderstanding *me* :) and I think that's my fault
because of how I said this.

Read the first line again: Fuel dumped in to the engine is determined by
the air flow plate position, not the throttle position.

That is 100% correct. Look at where your fuel distributor is located. On
the throttle body? Didn't think so.. it's above the air flow plate."
But, the AFM does not drive the car, the T/B does...  The T/B is what
affects the AFM, not the other way around...

As far as deceleration, I may have been a bit off. I don't know the exact
dynamics. You state "The airflow plate is not lifted at coast at all...".
I don't know conclusively if this is true or not true.

I do know that when I'm driving in my 16v and get off the throttle to
start to coast, the car responds slightly differently than if I reach down
in to my fusebox and pull the fuel pump relay.
This is true, if you have no fuel flow while on the highway, it will act
differently than if you were coasting with it in gear...  So, we would have
to both agree that there is some fuel flow, perhaps the same amount that
flows when the car is idling?  Or close to the same amount, depending on
relative RPM?


"You may be correct, and this may just be my imagination.. but I have the
opinion I have based on observation and some mild thinking.

My thoughts are -- yes, the TB is closed when you're coasting, but there
is a TB bypass path (this is how the engine gets air when it's at idle).
Furthermore, the amount of vacuum at a motor's intake is proportional to
the rpm the motor is turning at. Therefore I say that at 7000 rpm there is
more vacuum at the intake than at idle. Greater vacuum with the same sized
bypass can pull more air (think of this as one compressed air line at
30psi and one at 90psi.. the one at 90 can move more air through the same
sized hose) and as a result create more vacuum above the air flow plate
than when the engine is at idle. Not -as much- vacuum as with the
butterflies open, but more than at idle. So you're still burning fuel."
Yes, I agree...


Again, this is purely theory and unscientific observation. I may be
wrong, but perhaps not. I'm not going to stick up for this opinion the way
you're sticking to your guns about the flywheel thing because I don't feel
like I can back it up.

Well, if I built the Titanic, I would not have admitted it after it sunk,
but I am slowly getting a sinking feeling here...  I still cannot let it go
just yet, but I feel that there is something I am missing to make it work,
or even to let it go...

The flywheel, OTOH, I'm sure about :)

OTOH?
David

-Toby