Mileage with a Motor Home

[Raymond C Drouillard]

On Mon, 30 Mar 1998 23:50:39 -0500 "Bernie Jacobsen"
<bcjac at ix.netcom.com> writes:

>>Maximizing vacuum increases mileage?  What about pumping losses?
>>
>>If I find the speed of maximum torque on my 360 Jeep engine, should I
set
>>it up to run at that speed when I am cruising?
>
>How will you find this?  Dyno?  If so,  do you know what your manifold
vac
>is when cruising?  Use that on the dyno. Measure fuel usage at that
level of
>manifold vac. at various RPM's. This will tell you a lot.

I am thinking of using a two-part method.  The first part will be easier
if I can find a way to send the speedometer pulses from my cruise control
into the Holley ECU, and have them recorded with the HONDO (on-board data
gathering) program.  First, I'll go to a truck weigh station and get the
Jeep weighed.  Then, I'll accelerate to 80 or 90, put the transmission in
neutral, and record my speed as the friction slows the vehicle down.  If
I make several runs in opposite directions, I'll be able to get a good
curve of friction vs. speed

The next step is to record acceleration at WOT.  I'll do that a few times
in opposite directions.  After a few calculations, I'll have a good
torque curve, corrected for transmission/t-case drag and torque converter
slippage and torque multiplication.

I can get a good estimate of where the max lies just by accelerating and
crunching the numbers and skip all of the other stuff, of course.

"An engineer will calculate it to ten places, measure it with a
micrometer, draw it with chalk, and put it toghether with a monkey
wrench."


>
>>
>>Ray Drouillard
>>'89 Grand Wagoneer
>>Holley Pro-Jection, Jacobs ignition, Edelbrock performer manifold,
Engine
>>Guard pre-luber, 3" exhaust system, 30x9.5 tires, stock 2.72:1 axles
>
>That's pretty tall! you are probably under 2,000 rpm when cruising at
60. Of
>course that's not so tall if you normally cruise at 80.

I like to cruise at around 80 :)   Trouble is, my GW has the aerodynamics
of a box.  Ah, well... there's more to life than gas mileage.  Converting
to run propane or methane would help, especially since it's so easy to
generate your own methane.

>
>^Bernie
>

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