From: ak954@yfn.ysu.edu (Albion H. Bowers)
Subject: Re: Manual Shift Bigots
Organization: St. Elizabeth Hospital, Youngstown, OH
Lines: 48
Reply-To: ak954@yfn.ysu.edu (Albion H. Bowers)
NNTP-Posting-Host: yfn.ysu.edu


In a previous article,  (Eric Youngblood) says:

>In article <Apr19.195700.19699@engr.washington.edu>, eliot@stalfos.engr.washington.edu (eliot) writes:

>[race car stuff deleted]

Back to the F1 stuff for a second, note that the `auto' tranny in F1
_STILL_ shifts at the driver's command, not some preselected schedule.  The
driver still controls the shifting, not the transmission. 

>|> now, there is no dispute that in production cars, automatics are
>|> inherently more lossy than manuals.  that is in theory.  my point all
>|> along is that whatever mechanical advantages a manual has over an
>|> automatic can very easily be lost by a driver who isn't skillful or

>One thing that gives an automatic an advantage at launch is the fact that
>it has a torque converter vs a clutch.  I know this sounds strange but,
>a torque converter multiplies the engine output when launching.  It functions
          ^^^^^^^^^ ^^^^^^^^^^^
>as a sort of limited Continuously Variable Transmission. Typically you get 
>a torque multiplication of 2 to 3 times depending on the stall speed.

I have yet to see a torque multiplier installed on a production automobile. 
Such systems do exist, but none are presently installed in production autos
that I am aware of.  These are commonly called viscous drive CVTs or
fluidic amplifiers. 

>Contrasted to a clutch which merely slips when feathered (result is no TQ mult)

What the convertor _does_ allow is for the engine to be closer to its
torque peak during the launch before a clutched car can fully engage it's
driveline.  Chevy proved it many years ago with the '70 Camaro (ETs and
terminal 1/4 mile times were close enough tpo be identical for 4 speed and
auto cars).  Note that this is also the major reason that an auto car can
get away with fewer gears than a manual, the slip in the convertor makes up
for the fewer ratios (and before everyone starts yelling about the proposed
5 sspeed autos soon to be out, note that some manufacturers are using 6
speed manulas now). 

>Once past lauch however, the converter begins coupling and the TQ multiplication
>effect is reduced, but by then you should be on the cam.

Correct.
-- 
Al Bowers  DOD #900  Alfa  Ducati  Hobie  Kottke  'blad  Iaido  NASA
"Well goodness sakes...don't you know that girls can't play guitar?"
                                             -Mary Chapin-Carpenter
