Optimum shifts

[rob hod]

    Hi chaps,

    I haven't been following this one at all closely, but the engines torque
peak is not the most important (or relevant) point.

    What you need to get off down the road as fast as possible and impress
the hell out of everyone around is Power.
    The mass of your car, which has to be shifted, needs kinetic energy
adding as quickly as possible. For the engine that translates into a
requirement for maximum power, which after all is torque X revolutions.

    In the perfect world which we all know is somewhere off the coast of New
Zealand you would have a no-loss infinitely variable transmission which
would allow your engine to stay at the revs that correspond to maximum
power.
    In the real world , which may involved a selection of gears, this
translates to looking at the power curve either side of the peak and at the
gaps between the gears.

    Extreme example 1, - you have an engine with a sharp loss in power after
maximum and a close ratio gearbox - in this situation change up immediately
after hitting maximum revs.

    Extreme example 2, - you have a curve with hardly any power until a
sharp peak, and then a gradual fall off in power as revs increase, you also
have a massive gap between ratio one and two, - in this case keep going well
past peak power before changing up so as to minimise dropping into the
(relative) low power zone below peak.

    Just to recap , don't worry about torque, - the gearbox is a torque
multiplier!, how you utilise the peak power zone is what its all about.

    HTH .

rob
----- Original Message ----- > Message: 1
> From: "ricematthews" <ricematthews at msn.com>
> To: <brogers at terrix.com>, <jonboyer at hotmail.com>
> Cc: <quattro at audifans.com>, <urq at audifans.com>
> Subject: Re: Optimum shifts
> Date: Wed, 17 Apr 2002 08:03:54 -0400
>
> For maximum acceleration, you want to maximize torque.  So, practically
> speaking, you typically DO want to shift somewhere after peak torque and
> such that you hit the next gear somewhere before peak torque.
>
> Theoretically, to say exactly where to shift, you must consider the torque
> curve and your gear ratios.  You want to maximize the total area under the
> torque curve(s) in all gears (Calculus II anyone?).
>
> -Mark Rice
>
> *****************************************************
> >
> >Hi all-
> >I was browsing through some Audi sites and saw some hp/torque graphs.
> >According to the graphs, where is it best to shift up to the next
> >gear.....right after hp peaks?  Or does it also depend on where torque
is,
> >too?
> >
> >Does anybody have hp/torque graphs for a modded 10V turbo?  Something
> >basically along these lines:
> >
> >2.1 liter WX engine
> >K24 w/ 15 psi boost level
> >268/270 cam
> >IA chip
> >K&N filter
> >free flow exhaust (no center)
> >
> >Thanks for any info.
> >
> >Brandon
> >'84 ur
> >'98 A4
>
>
>