Engine swap fuel efficiency?

[cranetruck]

Eric, my multi was naturally aspirated when I got the truck. It would only smoke when loaded
down at first (hitting a hill, for example), but cleared up moments later.
Don't see how "turning down" the fuel delivery will help.
The engine only uses what it needs to maintain a certain rpm, set by the accelerator pedal or idle adjustment.
If your injectors are not performing, you may have incomplete combustion.

Also, if you idle the engine a lot you should take it for a long hard drive to "clear the pipes" as it were.
Keep the radiator covered to make sure your engine operating temp is where it belongs (175-185F),
if nothing else,stick a cardboard in front.
I feel that my engine is running as it should, but after long "idleing" times (1,000-1,400 rpm), like in operating
the crane at standstill, it takes 10-20 minutes on the highway to clear up the exhaust and my engine now has a turbo
and rarily produce any visible smoke when warmed up.

 

[Trango]

If you're blowing black smoke, well, that's the engine throwing unused fuel into the atmosphere. Literally, black smoke are little droplets of diesel encapsulated in carbon, which aren't being burned because there's not enough air in the combustion chamber. There is a point for every N/A diesel engine where turning up the fuel screw has no effect, and you're past that point.

If you want to increase MPG, you either have to put more air into the system to burn the fuel more completely, or take some of the unburned fuel out of the mix by turning down the fuel screw.

Oh yeah... I don't believe you can damage the engine to by leaning out these engines. Leaning out a gas engine will cause predetonation of the fuel air mixture, but since these guys rely on fuel ignition for both fuel/air mixture AND ignition, you're unlikely to cause predetonation. Just my understanding... I know MF engines are different than standard diesels, but if they have an injection pump, I'd say you're safe to lean out as much as you want.... until it doesn't run anymore.

Hope this helps
Bob

 

[cranetruck]

You may need to check the timing also. The details involved are shown in the images below.
The mark to use on the damper is the middle (20 deg) one for the LD-465-1.

If you need "How to" instructiuons, let me know.

 

[rmgill]

My initial calculations full tank, run x miles, then fill the tank up again and use that point for the amount of fuel used said I was getting 14 mpg, that surprised me, but I kept idling down to 3 hours for 16 hours driven, so perhaps that helped a touch. And I was going 45-50 on average, with a sortie to 55 for the bottom of hills where I could use inertia to get part way up the next one before going back down to 40mph on the climb with flashers on. It sure was a lot of work.

 

[cranetruck]

Well Ryan, it looks like we have the beginings of bell curve here...
if we could only get about 100 more respondees..

 

[SasquatchSanta]

When attempting to track fuel mileage topping-off the fuel tank to a consistent level is a challenge.

I drilled a 3/16 hole in the fueling tube. It serves an an accurate benchmark when fueling.

 

[gimpyrobb]

Earnie, that is a great idea. I will incorporate it very soon!

 

[m-35tom]

cummins 5.9 in a deuce always gets 15 or better but it is a way more effecient engine. ship i am on now gets 1 day = 48,000 gals

 

[jeli]

Over on another site for Duramax diesels guys with 4500 or 5500 4x4's are reporting 10-14 empty and 7-10 loaded. A 4x4 5500 has got to weight 11K. My 2500HD wieghts over 7K. One guy reported 8 mpg pulling 16K. I hauled 9K of rock in my deuce and there is no comparision the pulling power of a multifuel compared to a Dmax. I'd guess any Dmax, Powerstroke, or 5.9 Cummins should get low to mid teens in an empty deuce.

 

[alphadeltaromeo]

cummins 5.9 in a deuce always gets 15 or better but it is a way more effecient engine.

Not to be adversarial at all, but what are you referencing this on? Do you have real data to share? Reason why I'm asking...it's not just a weight discussion or debate...such as:

An individual has a modern diesel with a 5.9 towing an x-thousand lbs trailer equaling the weight of the deuce...so it should get x-mileage.

It also depends on how efficient the tranny/transfer (how much does it suck outa efficiency), axle ratio and tire size is with the multi. Just curious as to your thoughts?

Andy

 

[Barrman]

When Sermis, Kwai and I drove back from the GA rally. We got a consistant 10.0 mpg. That was fill to the top, get in, run 100 miles, switch drivers, run 100 miles, stop eat, switch drivers, run 100 miles, fill full of fuel to the top, switch drivers, run 100 miles, repeat... M35A2C with the compensator bypassed, lock out hubs on front and front rear axle shaft pulled. 9.00-20 duals following a Ford SD with the cruise set at 56 mph for 900 miles.

 

[gimpyrobb]

The FDC was bypassed! I wondered why it felt so strong! I think the 109 has some mods in its future...

 

[OPCOM]

what will happen to the transmission when the 610 ft-lb of torque occurs?

 

[ken]

I got 14 once. It was comming back from palestine texas. Running 45MPH empty. I have airshift and lockouts on the front. Last time i checked i got 12 on houston freeways running 50-55. On #2 diesel. 10% WMO is good for 1MPG better. In my tests. But it's easier for me to check milage from the engine hours. Mine spends alot of time offroad. I have recently done some turbo mods so i'm going to run it to beaumont soon and see what it gets. I can tell a power increase with less smoke, so hopefully it responds in the MPG dept also. 5mpg for a N/A multi doesen't sound too bad. I agree with bjorn. turning down the fuel won't make much difference. You would just be pushing the throttle down more to get the same result. N/A engines have a exasut pipe soo small i don't think i could breath through it. Not to mention the muffler set up. I'd also check the IP timing. Mabye it's retarded a little and the fuel is comming in too late. Also try removing the intake runner at the intake manafold and remove the rough casting burs and rough finish of every part of the air intake. This will take some turbulance out of the air flow and let it breath a little better. No it won't make a big difference. But it won't hurt. And at 5MPG anything will make a difference

 

[cranetruck]

Wonder if ability to start without starting aids is a sign of engine combustion efficiency....
What other engine has a compression ratio of 22:1?

I thought Tom had a Cat in his deuce.....

 

[Pappa-G]

When I had My M185A3 I would get 10 mpg , I got 8mpg on the way back while flat towing a M1009 400 miles each way fully loaded. Your results may vary.

 

[spicergear]

I'm running at 1160 CAT (virtually the same as 320 that's a 225hp NA engine. The later 3208's only went to 190hp or 195hp before a turbo was added so I think it's safe to say that this engine has the fuel put to it a bit. It seems to be set up well at that hp level too as it rarely shows any smoke under load and burns real clean. Don't have any mpg figures but will be able to work on that a little more here soon.

 

[gimpyrobb]

Yeah but, comparing Tom's deuce to any other deuce is like comparing apples and squash.

 

[spicergear]

Thanks GR-

Bjorn, what's your empty weight now? I'm at 18,000 lbs with 8,000 lbs on the nose and 10,000 lbs on the tandems.

 

[cranetruck]

About 17,000 with the crane and the pipeline bed.