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Re: somebody explain shifting and RPM to me

To: "mgs" <mgs@autox.team.net>
Subject: Re: somebody explain shifting and RPM to me
From: Larry Macy <macy@bblmail.psycha.upenn.edu>
Date: Tue, 14 Nov 2000 18:41:08 -0500
I was sitting on the train tonight, on the way home, getting ready to 
drive the Midget, top down of course, on a cold and windy night.  What 
did I have for reading material, why the  Dec R&T. On page 166 is an 
article by Dennis Simanaitis, in the Tech Tidbits column, that relates to 
this thread.

Not been reading R&T lately?? Anyway it seems taht in 1981 BMW did a 
study relating throttle position (acceleration), shift points, and fuel 
economy. They determined that rapid acceleration and short shifting made 
for the best fuel economy. That is 3/4 throttle to 2000 RPM and shift 
gave 21.4 mpg, 3/4 to 5000 RPM gave 18.1 mpg. And low throttle, termend 
Pop's Driving School Egg Under the Gas Pedal Method, shifting at 2000 RPM 
gave 13.8 mpg, and the "egg" method, shifting at 5000 RPM gave 9.4 MPG. 

BMW went so far as to offer a 528e with driving instructions to suit. 

The theory is that that, yes revs cost fuel due to increases in friction, 
but the pumping losses are less at wide open throttle. Apparently the 
lower pumping losss make up for increasing the friction loss.

I didn't write it I just relay it. But it makes sense to me.

BTW R&T is online at www.roadandtrack.com. They usually have the articles 
from each print issue online sometime after publication. I just checked 
and the issue online is still last months. So if you don't get R&T either 
check this out in a few weeks, borrow a copy or run down to the local 
library and do something completely unusual in this day and age, read a 
magazin in its paper form ;-)

Larry

Larry Macy
78 Midget

Keep your top down and your chin up.

Larry B. Macy, Ph.D.
macy@bblmail.psycha.upenn.edu
System Manager/Administrator
Neuropsychiatry Section
Department of Psychiatry
University of Pennsylvania
3400 Spruce St. - 10 Gates
Philadelphia, PA 19104

 Ask a question and you're a fool for three minutes; do not ask a 
question and you're a fool for the rest of your life. 

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