Well you could always engage the Cruise Control to maintain speed.
-----Original Message-----
From: snyler <marc@animalfirm.com>
To: Ryan, Richard <RRyan@frk.com>; 'datsunmike' <datsunmike@nyc.rr.com>;
'Datsun Roadsters' <datsun-roadsters@autox.team.net>
Date: Friday, February 09, 2001 2:23 PM
Subject: RE: Gas Mileage
>Ryan, Richard wrote
>
>>So the real question is: At which rpm (3,200 or 4,000) does the engine
>>produce 30 hp most efficiently.
>>
>>And the answer is: Beats the hell outta me. I don't have any engine
>>design info that I can use to get the answer. Some have commented that
>>changing axle ratios and/or tire sizes will change the equation. That is
>>correct because changes the 2 rpm points and the efficiency will be
>>different at those rpm.
>Find out empirically. Plot out a flat level run on the interstate of,
>say 35 miles out, and 35 miles back. Use a gas station as your base camp.
>Fill the tank. Make your first run at 70 mph in 4th gear, 35 mi. out, 35
>mi back. Fill the tank at the same pump and record how much fuel it
>takes. Make run #2 :35 mi out, 35 mi back, at 70 mph in 5th gear. Fill
>up at the same pump and record how much fuel it takes. The run that
>takes less fuel is obviously the more efficient. The 4th gear run will
>spin the motor 56,000 more times on our 70 mile, 1 hour trip. Hard to
>imagine that your foot would be lighter on the gas in 4th than 5th to
>maintain 70 mph. I'm guessing you'd do better in 5th, but only
>experimentation will tell us for sure.
>
>-marc
>
>==========================================================================
>Marc Tyler
>Designer,
>Animal Firm
>830-324-6578
>www.animalfirm.com
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