On Thu, 07 Apr 2016 12:38:58 +0100, michael adams wrote:

"dennis@home" wrote in message
eb.com...
On 07/04/2016 10:19, michael adams wrote:

Given that torque is the power transmitted via the drive axle which
causes the wheels to rotate, its difficult to see what's wrong with
his claim, quite honestly.

Energy of moving object = mass x velocity squared.

If you want it to go faster you have to input energy.

Yes.


If the energy source has higher output at high revs you have more to
put in.


Yes.

In a car this quite often means changing gear and possible slipping the
clutch and is therefore a dynamic system and not a static one like
having an engine running at one speed at maximum torque.

See its easy to argue.

Only if you choose to deliberately conflate engine torque, which is
presumably measured at the flywheel, with driven axle torque which
actually turns the wheels.

I'm not concerned about the engine.

Yes but Dave was. If you carefully examine his statements in the post he
made 8 days back which I've quoted he

"And you'd get even more force at peak torque in that gear...


You get the best acceleration with the maximum torque *at the wheels*. And
in any given gear, this will be when the engine develops maximum torque."

You'll observe that, strictly speaking, they're actually true! :-)

He can't help it if others want to misinterpret the second statement as
implying best acceleration of a car being achieved by choosing to
maintain the engine speed at or close to peak torque revs rather than
peak power revs by choosing gear ratios to maintain this state. :-)

I suspect Dave was merely trying to 'pep up' the debate, relying on our
human propensity to read into such bare statements their own
interpretation of the 'question' thus posed. Even I failed to observe the
strictness applied to those statements (Damn! Where *is* a "Sheldon
Cooper" when you need one?)


For the wheels to be turning or accelerating fastest -
in the absence of the car being powered by external factors such as the
wind propelling the body, they need to be subject to the maximum
available torque.

More accurately, that last statement would be better paraphrased as,

"they need to be subject to the maximum torque available at that road
speed."


Quite how it got there, is an entirely different question.

Quite! For most of us here, including myself, this is a matter dealt
with by optimal use of the gearbox to operate the engine as close to its
maximum power output revs rather than the, as implied by Dave's
statements, maximum engine torque revs.

--
Johnny B Good