On 31/03/2016 01:22, Dave Plowman (News) wrote:
In article ,
Clive George wrote:
On 31/03/2016 00:43, Dave Plowman (News) wrote:
In article , Clive
George wrote:
We're not talking 0-60 times here. Just the best rate of change of
speed.

Ok. Which is achieved with the gear chosen so the engine at its
maximum power, not maximum torque.

You should join Turnip in some basic mechanical theory lessons.

The weird thing is you've just agreed with my statement in your previous
post.

At a given road speed, the maximum rate of change of road speed will
be achieved at the engine's maximum power point. The necessary gear
ratio to achieve this will be determined by the chosen road speed
and the engine's maximum power speed.

is a longer way of saying what I've just said, and you replied saying
"Yes".

Why agree with one yet disagree with the other?

Sigh. If you measure the time taken for say 5 mph increments in speed in
any one gear, the shortest time will be at peak torque. Not peak BHP.

You decided to choose a road speed where the engine was at peak BHP in
that gear. The only way to get the same road speed at peak torque would be
by using a higher gear, since peak torque is always at lower RPM than peak
BHP.

That doesn't explain why you disagree with what I said yet not with what
Roger said. None of what you've said just there disagrees with what I
said - best rate of change of speed is achieved with the gear chosen so
the engine at its maximum power, not maximum torque.

Or is this entire argument about you saying that the fastest instant
acceleration at all the road speeds between 0 and maximum speed will be
at the road speed where the engine is at peak torque in 1st gear? I
won't disagree with that, but don't think it's terribly useful, because
generally people are concerned with the fastest way of getting between
two road speeds (eg 20-60). And for that, the fastest way is to choose
the gear such that the engine is at or closest to maximum power, not
maximum torque. Ie change up late, not early.