Miata Mailing List: December 1998, Message #357

sponsored by

Paul,
The only problem with your test is that you are assuming that your
speedometer and tachometer are accurate.  I also assume my tach is
indicating correctly, but others have posted that it can easily be off by a
couple of hundred RPM.  More importantly, I *know* my speedo is off
(optimistic) by a couple of mph.  When it is indicating 60 mph, I'm
actually only doing around 57 mph (with my current tires, of course).
Magazine road tests and manufacturers data are usually conducted with a
calibrated speed measuring device, that does not necessarily agree
precisely with what our dashboard instruments are telling us!

I've seen the speed in gears numbers, and have always assumed they are
referring to calibrated speeds, using stock tire diameters.

If the tire size (diameter) changes, the speeds in gear and the speedo
error will change also.  For example, if I were to put 165/60-14 tires on
my Miata (smaller diameter), I could probably reduce my 0-60 time by 1
second as clocked from my speedometer.  However, because of the speedo
error introduced by the smaller diameter tire, I'd really only be measuring
0-52 mph, even though the speedometer still says 60 mph.

FWIW,
Gordon Choate
Calgary, Alberta
96 BRG/tan






Paul Lu <ataym@yahoo.com> on 12/02/98 05:18:38 PM

Please respond to Paul Lu <ataym@yahoo.com>

To:   Multiple recipients of list <miata@list.miata.net>
cc:    (bcc: Gordon Choate/NOWSCO)
Subject:  60mph in 2nd gear




Just to answer someone who showed me the spec about fuel cut-off
should happen before 58mph.

In the low 70F for December, just got to have fun with the little
roadster.

Was on a road going up the hill - not too steep. Changed into 2nd just
bellow 30mph and watched mYata hit 55mph while it ran up 6000rpm. It
was in the red zone just bellow 7000rpm when it reached 60mph.

Not that I will do this often, just to prove it. Normally, changing
gear at 20, 40 and 60mph is considered aggressive driving. A more used
measurement is 40 to 70 mph and this happens in 3rd or 4th depends on
situation.

Anyway, I tried the 60mph again. This time, I was in second at between
15 to 20 mph and got a chance to try it. The discusting fuel cut off
did kick in arround 58/59; however, a step on the gas got enough push
to go over 60mph ( with a caugh ).

Tried a third time just to give myself a proof. The key is to rev high
and keep the engine in the "fun" mode ( as oppose to the "suck" mode
when I will call it not much of a sports car ).

Chances are I will be in 3rd when the car goes over 45mph for most of
the cases. I do know that I will only change gear once if I were to
give a 0 to 60 time.

Paul



==
On the Cyber Space, we might have a peek to the future.
For the better or the worse, it's all in our hands.

mYata


_________________________________________________________
DO YOU YAHOO!?
Get your free @yahoo.com address at http://mail.yahoo.com