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Mileage and the modified Big 6.......

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Mileage and the modified Big 6.......

Post #1 by mutt » Sat Aug 17, 2013 1:19 pm

Of course, us Ekonomen are the superstars of the Ford Truck world! Ekonokrates aren't for just anybody, after all. But with all great powers comes great responsibility. In our case, its staying below 60MPH if you are trying to get any mileage. Thats our critical mach number..... and even there, you are facing a drop in MPG.
My rig: 80 E 150, Big Six, 4 sp (OD) tranny. 3.83 limited slip. 7.00-15 yokohama high profile light truck- look like bias ply, now unobtainable, just about. 50psi fr, 55 rear. Offy manifold with flipped over 2 to 4bbl adapter, a '68 vintage Motorcraft 2150 carb, 1.81 venturi- the big one. "Power valve" for 2 inHg. Port matched, head milled .025, combustion chamber relieved around the intake valve, the intake bowl opened up. FI ex manifolds thru a gutted cat into a cherry bomb and exits before r wheel. Stock cam "straight up" w/ Cloyes variable timing gear. No roof rack. FI type plugs.... & Chev rockers. When I got it, stock and California smog legal, it wouldn't get 13mpg and OD could only be used downhill and it had a 3.08 rear end.

The run from Toronto to Montana is pretty flat. I had my stripped down 80 Harley in the truck and 300 lbs- spare, jack, tools, assorted gear, plus Im 250. towing a trailer thats at least 500 lbs, w/ The Girls Road King on that- jeez that beast gotta go 700 lbs. (I'm not out of ontario & the clutch slipped pulling a hill- I backed off immediately. Uhoh. Do I turn around and R&R the clutch, or do I take it VERY easy & swap out the clutch in Montana? I chose the latter.) SO......... at 65-70 MPH, I was getting 14-15-16 MPG. I checked my odometer against mile markers- a hundred miles on the markers gave me almost exactly 107 on the odo. So I factored that in when computing my mileage. At night, I drive slower...... and I got some remarkable results. Such as staying between 50 and 55 got me consistently 19-20-21 MPG. i was really able to be precise driving across N Dakota at night. The bad clutch kept me honest and easy on the gas. But there it is: 10 MPH faster costs you 5-6 MPG. Rather remarkable, but that handsomely distinctive Ekonokrate form carries a heck of an aerodynamic price. Oh, yeah: I got a big vacuum gauge, I was able to pull 10 in or better at 50-55 in OD on the flats. but it didn't take much for the vac. to drop, so it put it in third to keep the vacuum, thus efficiency-high, I THINK the added RPM vs the higher vacuum wins you the MPG game, but thats just a seat of the pants notion. 89 octane, mostly, but on higher ground 85. No knocking ever. initial timing 8btdc, stock ignition, "blue" ferrule brain box.

In Montana I got a $85 tranny jack, a heavy duty clutch, TO & pilot bearing, and swapped it out next to my cabin. Old guy stylee! That tranny jack replaced two strong hippies, and it don't drink your beer and mooch your weed, tell you whut. i was chuffed..... of course wire brushing the hardened mud offa all the fasteners was a job all its own. Greased the heck out of the floor shifter, that worked wonders, too.

I got about 40K since I ringed it.....stock bore, barely could feel the ridge-serious nickel in that block!- and new std pistons, the secret being Hastings Cast Iron rings. It burns a qt in 3k miles, still. I think the odometer is telling me thats 280K miles... it was a fleet truck before I bought it, and they changed the oil regularly. Still no rust, but the doors are ratty. No junkers I can find up here in Toronto, Id like to find some better stuff....... anyway, thats my MPG report.... I think the key to bettering that is milling the block for zero deck, and bumping the CR. 8.75,thereabouts. Mutt.

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Re: Mileage and the modified Big 6.......

Post #2 by Nashtooth » Sun Aug 18, 2013 9:01 pm

I'm an Econokrater with an 84 E 150 shortie with the usual stuff on the engine, a C 6 and a 3:1 3rd member, and I have also owned an areostar...what if we could morph those shapes?

Seattle Smitty

Re: Mileage and the modified Big 6.......

Post #3 by Seattle Smitty » Tue Aug 20, 2013 2:05 pm

Mutt, it sounds like the real key is having to favor a dying clutch with an extra-sensitive foot on the gas pedal.

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