MAX Update No. 84: Speed Kills (Gas Mileage)


| 11/18/2011 2:49:20 PM


Tags: MAX, 100 mpg, Jack McCornack, Seven Springs 2011, Mother Earth News Fair 2011,

In my 7,500-plus mile adventure in MAX this summer, one lesson really stands out: Haste Makes Waste.

To make a long story short, when George Voll and I drove our high mileage cars (that’s George’s car in the background) from his home in Indiana to the MOTHER EARTH NEWS FAIR in Pennsylvania, we drove various legs of the trip at various speeds. By driving in formation and scrutinizing each other’s fill-ups, we got two-heads-are-better-than-one confirmation of our mileage.

The above photo shows my side of the fuel pump, just east of Columbus Ohio, after our 100.4 mile, 45 mph run from Cleveland. I confirmed speed and distance with my GPS, but for most of the trip George’s diesel Metro was the pace car.

We had driven that leg at 45 mph for three reasons; first, George had never driven a hundred miles that slowly and didn’t know what his mileage was down there; second, 45 mph was the minimum speed when the Auto X Prize did its oval track “race” last year and we wanted to measure ourselves against that benchmark, and third, it was raining hard when we left Cleveland and it’s uncomfortable to drive MAX fast in the rain.

MAX and Diesel Geo Metro at Gas Station 



Mercifully it quit raining as we approached Columbus, so I was able to pack up my motorcycle rain suit (it’s in the black Triumph bag sitting on MAX’s “trunk”) and wring the rainwater out of my earplugs (no, I’m not kidding — the rain suit keeps my body toasty but rain blows in between my helmet and my ears, and if there’s lots of rain, my foam ear plugs soak it up). After this ordeal, my rain suit stayed packed and my ear plugs stayed dry for the rest of my trip — to Pennsylvania and all the way back to Oregon afterward. But I’m drifting off subject; I’ll write about rain some other day.

Jack Leffler
12/9/2011 3:13:49 PM

Although I believe there is a drop in MPG when your speed increase it is something that is not accurately assessed on th open interstate. The highways traveled on this trip vary to much in terrain. And running across South Dakota (East to West) you have a steady uphill climb from the Missouri to the Rockys. This and the normal summer headwinds from the west greatly affect the fuel mileage (trust me, I've driven the route often). All this being said: avoid being a hazard, drive the speed limit. And I'd like to have either of the vehicles for my long trips.


JACK MCCORNACK
12/8/2011 1:40:21 AM

Jeff (this is in reply to the reply below--I couldn't reply to it directly 'cause this blog program only allows 5 links in the reply to a reply to a reply etc etc chain) re excess power @ 55 mph, with the old body I'd say "yes" and with the new body I'd say "yes indeed", thanks to the streamlining. I'm sure I could shift up into 6th gear if I had one but I wouldn't expect huge mileage gains from it. MAX is geared a bit taller than before (by final drive ratio and by tire diameter) and heavier with the full body so I use 1st gear for all my starts now. And when I'm accelerating from 45 mph, I normally leave it in 5th gear...unless I'm passing or something else where haste is in order; then I'll downshift.


JEFF DEAN
12/8/2011 12:15:38 AM

Jack, thanks for your reply. How does Max "feel" when driving? I recall you writing that first gear was hardly necessary, that you could start in second with no problem. Does max have any excess power at 55 mph? Do you think you could shift up (if Max had a sixth gear)? Is there plenty of power going from 45 mph to 55 mph in fifth gear, or do you need to down shift?







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