12.5 MPG in a Deuce?

[houdel]

I've been somewhat curious what sort of fuel mileage I'm getting with my Deuce, so I ran a little test. My fuel gauge doesn't work (although I did fix that yesterday with a new fuel gauge), so I had made up a dip stick calibrated in gallons in order to keep track of how much fuel I had in the tank.

I started my test on June 27, according to my dip stick I has 20.6 gallons in my tank and my odometer reading was 16894.5 miles. I ended on August 10, my dip stick read 20.4 gallons in the tank, my odometer reading was 17194.3 miles, and I had purchased 24.99 gallons of fuel in that period.

With a little simple math, that comes up with 25.2 gallons used to drive 299.8 miles, or 11.89 mpg. However, my odometer reads 5% low, as verified by both my GPS and comparison readings for point to point trips with my '05 Chevy Venture. Figuring in the 5% correction, my actual mileage for the Deuce is 12.51 mpg!

I was impressed, to say the least! I was expecting 8-10 mpg at best. But I am running singles on the rear, and most of my driving is on rural roads at 40-50 mph. Only about 100 miles was at highway speeds in the 55-60 mph range (actual speed per my GPS, the speedometer reads about 10% low).

All in all, not too bad. I've owned several 1/2 and 3/4 ton pickup trucks that only averaged 12-15 mpg, so I guess I'm doing OK with my Deuce!

 

[SasquatchSanta]

Hello Lee,

Thanks for furnising this info --- very interesting AND encouraging.

With fuel prices going up the way they are I think deuce owners are going to start paying closer attention and trying to figure out ways to increase fuel their economy.

I'm going to launch a major campaign on increasing the fuel mileage on my M35 4X4. I wish I knew your secrets --- the settings on your deuce.

Do you know what your pump setting and idnition timing is? Has the IP been turned up?

I'll keep you posted my progress.

 

[Recovry4x4]

Best I've ever done is 11.4 and that was in the lighter tractor with despilend front hubs and one rear axle removed. Speed was kept to 52 MPH. On the next tank I jumped the speed to 55 and mileage dropped to 9. I have to admit though, the gauge doesn't work and the long flat tank of the tractor combined with the odd angle of the filler makes precise filling and measuring all but impossiblle.

 

[cranetruck]

My deuce weighs 17,000 lb empty and the best I have recorded is between 9 and 10 mpg, guess 12 isn't impossible, the multifuel engine is very efficient, that's a fact.
The Hypercycle combustion process, patented in Germany (MAN) in the 1950's and claims that one of the benefits is just that, higher efficiency.

 

[devilman96]

I was talking to Ken about this the other night with my truck... I was getting about 9.7GPM on my trip down here when the truck was stock but was running a top speed of 63 MPH @ 2600 RPM which was verified by the chase truck at the time (my odometer was saying 60-61)... Which does not at all seem right with gearing and stock NDC's.

Ken mentioned that there was a rumored production transmission with a higher OD ratio in it that might make this possible. I have a hard time seeing a mechanical tach being very far off and as I said it was stock so my fuel and linkage settings were the same. Maybe since the truck had a 1991 overhaul I got a different trans gearing or something but I wish there was a way to verify this without tearing it down.

Anyone know anything about such a transmission or is this another one of those allusively sought after things that a friend of a friend had seen and knew about manufactured by Lock Ness or Sasquatch Skunk Werkz like the stock Military or Thermo King AC units???

Reguardless I am ITCHING to get this thing out on the road with the 4X4 job done... I can say with just driving it around locally the take off speed and handling were kinda scary for such a large truck.

 

[SasquatchSanta]

There seems to be some confusion as to whether 5th gear (overdrive) is a .079 or a .085 ratio.

Can enyone clear this up and if both ratios exist how we can tell by looking at a transmission which ratio applies.

 

[ken]

12.5 shouldn't be a problem with a M35. D-RAT got 11.8 in a 109 comming back from kenny's with a traveltrailor in tow. Lock out hubs gave me 1.5 mpg better. The best i've ever done was comming back from palestine texas empty. At 13.8, i ran 40 to 45 mph. Anything above 50 and it drops below 10MPG.

 

[houdel]

Well, I have three pretty good reasons why my fuel mileage is so high, and a couple of maybes. First, my driving is pretty conservative - as I stated, rural driving, mostly topping out in 40-50 mph range, and often even slower than that, probably average speeds in the high 30's. Second, I'm running singles on the rear, no hub flip yet, thats on the to do list, but singles have to help mileage somewhat. And third, my truck is empty 99.9% of the time, the heaviest load I've carried to date was a single treated 4"x4"x8', so I haven't used much fuel carrying a load.

As for the maybes - I'm pretty sure my fuel rate was turned down pretty low. My truck had been a real bear to start, and driving home from the DRMO, mostly on flat Interstate, the fastest I could go was an indicated 54 mph (actual 58-60 mph per chase car and later confirmed with GPS) at 2450 rpm, it never ran any faster than that except for on downslopes. NEVER smoked any, either. I recently turned up my fuel one flat on the nut (1/6 turn), starting was much improved and I could see an occasional puff of exhaust smoke. Now I've cranked it up another flat (to two flats, 1/3 turn total), it starts in an instant and will blow smoke going up through the gears. No more fuel adjustments until I get a pyrometer installed though! Thats at the top of the to do list!

As for the second maybe, I have to agree with Devilman96, I don't think I have the standard .78 OD ratio. I'm running an honest 55 mph (per my GPS) at 2300 indicated rpm. Unless my tach is off, by my calculations my OD ratio is somewheres between .70 and .75. My transmission is a Spicer Wolverhampton 3053, NOT a 3053A or 3053B, just plain old 3053. Maybe the Brits ran did something different. Also on my to do list is to mark the harmonic balancer and trans driveshaft flange, turn the engine over 4 full revs by hand and count the revs on the driveshaft, that will answer the question fully. As I said, its on the to do list, along with the pyrometer, replacing a knuckle boot and a few more pressing things, but eventually I will get around to calculating my actual OD ratio and post it in this forum.

 

[houdel]

Ernie - Per TM 9-2320-316-20, fifth speed (OD) is 0.79.

 

[OPCOM]

bad table, but the 3053B has the better OD

Spicer 3053 16.5" case Spicer 3053A Spicer 3053B

1st 5.90 6.00 4.5

2nd 3.10 3.31 2.5

3rd 1.70 1.89 1.5

4th 1.00 1.00 1.0

5th 0.85 0.85 0.75

rev 5.90

http://www.gag.com/~cabell/transmission.htm

 

[OPCOM]

Assuming the 3053B fits where the 3053A goes, I would like to obtain one! Sure first gear is not so hot but that is what the tranbsfer LOW range is for!

 

[SasquatchSanta]

Does anyone know what would be involved in havng higher speed overdrive gear sets built and if it is feasible?

It would probably take a production run order of several sets to get the cost per unit under control BUT there might be sufficient demand to justify a production run.

 

[rdixiemiller]

Taller OD, lower RPM, more throttle needed to maintain speed, less power, lugging.....engine damage......
Mine is OK like it is. I would like another gear between 3rd and 4th, but the OD ratio is OK by me. These things aren't built for speed, and 1mpg is not much of a savings to me, I only log about 2500 miles a year, 250 gallons of fuel a year at 10 mpg. So I could possibly save 25-35 gallons a year.........
I prefer to cut my diesel with used motor oil. Easier.

 

[SasquatchSanta]

I just did a mileage test that indicated 12.28 MPG on a 10,500 lb bobbed deuce. The truck has 46.7" rubber, spin out front hubs and an electric cooling fan.

The test was done while mostly running 2150 RPM which, with the 46.7" rubber, equals approximately 56 MPH. At 2100 to 2200 RPM (during this test) EGT was around 650 with approx 3 pounds of boost.

I'm told the LDT465 produces it's maximum torque and gets it's maximum fuel economy at 2000 RPM. I'm also told that when RPMs reach 2200 both torque and fuel economy start falling off fast.

"In theory" would it be advantageous to attempt to change the gearing so the desired cruising speed (say 55 MPH) is as close to the 2000 RPM "sweat spot" as possible?

I should note that my truck is mainly a parade and hobby truck and thereofore is very seldom loaded heavy.

 

[rdixiemiller]

If you're getting 12.28, you are already way above what i would expect for a deuce. Losing the extra rear axle helps! I get 10 to 10.5 at 2100 rpm, de-splined front flanges and the interaxle shaft removed, 1100R20 singled radials. If I run at 2500 rpm, I get around 9.5.
I have run 25% and 50% used motor oil mixes with no apparent ill effects. The 25% mix barely changes the smoke color, power seems unaffected. I am probably going to standardise that as my preferred mix. That reduces my fuel cost dramatically, from $.28/mile to $.21/mile. The 50% mix runs me $.14/mile, even better.
Just as a comparison, my Suzuki Samurai averages 29mpg. With gas at $2.80, my cost per mile is $.097.
I don't feel too bad driving my deuce once or twice a week when I'm paying $.21 a mile. I'm in better shape than a lot of guys with standard pickup trucks.
I do like the electric fan, reducing the noise is something I want to do on mine.

 

[liljohn]

If you're getting 12.28, you are already way above what i would expect for a deuce. Losing the extra rear axle helps! I get 10 to 10.5 at 2100 rpm, de-splined front flanges and the interaxle shaft removed, 1100R20 singled radials. If I run at 2500 rpm, I get around 9.5.
I have run 25% and 50% used motor oil mixes with no apparent ill effects. The 25% mix barely changes the smoke color, power seems unaffected. I am probably going to standardise that as my preferred mix. That reduces my fuel cost dramatically, from $.28/mile to $.21/mile. The 50% mix runs me $.14/mile, even better.
Just as a comparison, my Suzuki Samurai averages 29mpg. With gas at $2.80, my cost per mile is $.097.
I don't feel too bad driving my deuce once or twice a week when I'm paying $.21 a mile. I'm in better shape than a lot of guys with standard pickup trucks.
I do like the electric fan, reducing the noise is something I want to do on mine.

Hey just out of curiosity where do you get your used motor oil?

 

[houdel]

Do you filter the used oil, or use it straight out of the drain bucket?

 

[rdixiemiller]

I get my used motor oil from an ambulance service. 15W40 from diesel engines. I run it through a 5 micron bag filter that has a 50 micron filter inside as a pre-filter (McMaster Carr specials). I pick up a drum or 2 a month.

 

[SasquatchSanta]

Do you have an opinion as to how 25% and 50% used oil to fuel blends tolerate cold weather?