Fuel efficiency question

[Jacka]

This question is for the true engine builders gurus.I am far from that.But running my David Brown today with its Alamo Boom mower gives you time to think.What makes one engine so much more fuel efficient than the next one? Is it head design,the way fuel is delivered, something about larger bore and shorter stroke or vice versa? Is it fly wheel size or weight? Why do different manufacturers have or used to have vast differences in fuel usage.I know my David Brown is as efficient as a tractor as they come.Its 65 hp or so.Plus it seems like the English or German tractors were more efficient back in the day.I know the Deutz owners always raved about them.

[Big Bud guy]

20 minutes ago, Jacka said:

What makes one engine so much more fuel efficient than the next one? 

The size of the fuel tank. 

[Alan Dinan]

Dad’s 1026 covered 110 acres planting corn on 20-21 gallons of fuel. It was full when he started and filled it up when he finished the field. 
My 284 pulling a 9’ rake runs about 2 gallons to rake 21 acres of heavy hay.

I have never tested anything with the 3688 or the hydro 86.

[Ihfan4life]

40 minutes ago, Jacka said:

This question is for the true engine builders gurus.I am far from that.But running my David Brown today with its Alamo Boom mower gives you time to think.What makes one engine so much more fuel efficient than the next one? Is it head design,the way fuel is delivered, something about larger bore and shorter stroke or vice versa? Is it fly wheel size or weight? Why do different manufacturers have or used to have vast differences in fuel usage.I know my David Brown is as efficient as a tractor as they come.Its 65 hp or so.Plus it seems like the English or German tractors were more efficient back in the day.I know the Deutz owners always raved about them.

What size DB? Mine was badged an Oliver and it would sip fuel. 

[MTB98]

It’s more what is attached to the engine than the engine itself. Any engine will need a certain amount of fuel to make x amount of power. That’s not going to vary much regardless of manufacturer. Things attached to the engine such as transmissions and hydro pumps along  with the weight of the tractor and tire size/weight all consume more power the engine must produce.  A little diesel gear drive 2wd pizza cutter wheeled tractor with minimal hydraulics will use a lot less fuel than a larger tractor with multiple hydraulic pumps and big tires and hydro transmission. 

[Jacka]

1 hour ago, Ihfan4life said:

What size DB? Mine was badged an Oliver and it would sip fuel. 

1210. 1.25 to 1.5 gal per hour running wide open on Alamo 5 ft brush axe boom mower

[naedlaen]

I think that for this discussion, you should define fuel efficiency.  Gallons per hour is different than gallons per acre or gallons per hour per horsepower.  I think that from a cost standpoint, maybe gallons per acre might be the best measure.  On the other hand, it makes no sense for me to buy the latest and greatest 100 hp tractor that would use less fuel per acre for my 9 acres of hay and 10 acres of pasture when a F656 will do all I need.  Would I like a disc-bine to mow with, yes, but it is less expensive to rent the neighbor's tractor and disc-bine for the 2 cuttings I make.  The same can be said about a snow blower.  

As an example of what I mean is at 3 mph, you are mowing about 1.25 acres an hour, so are using about 1 gallon per acre.  At 4 mph, 1.65 acres and 0.8 gph.  A slightly bigger tractor with a 10' mower might be more efficient per acre, especially if it can travel faster.  Cost of such increase in size might be the deciding factor.

Neal

[dale560]

Many pieces to the equation? Gas, diesel or propane they all have different amounts of energy per gallon. With the gas and propane, head design, cam profile, valve overlap engine timing all make a big impact as does bore and stroke of engine. 
deisel engines , injection type, valve design and all that figure in also. The older type of ign cycle the pre cup and power cell in diesel made a big difference. As does fuel quality 

[JaredT]

I think generically he is talking a known difference. Our 826 used to pick corn on 2/3 the fuel that our 986 would.  If you did the same job with a 1086 or a 4440, the 1086 would use way less fuel. I am with Jacka, why would one be way better than the other? Same Hp, less fuel, how? IH 400 series engines always were know to be efficient, why?

[stronger800]

We had s DB 880 when I was a kid. It would pull a 256 rake for Days on 5g of fuel.  
great little tractor 

[acem]

Honestly it's very complicated. It relates to so many things that work together and against each other.

Here's an example of  two cars.

A friend drives a  10? year model Dodge challenger with a V6. He gets 30 MPG on the highway.

My (step)son drives a 15? year old Honda Civic with a 4 cylinder. He gets 34 MPG on the highway.

They both drive the speed limit plus a little.

It makes no sense that the big Dodge Challenger with a 300 hp engine would get 30 mpg while the little Honda  Civic with 120 hp engine get 34 mpg! 

Fuel efficiency is complicated.

 

[PJW360]

I grew up with David Browns on the farm and yes they are well known for running on fresh air great tractors which bring back great memories for me

[TroyDairy]

Airflow and cylinder/vavale design lead to better or worse efficiency

But yeah running a blower wide open vs a mower are such different things. 

[Lazy WP]

Also makes a difference what the engine is pulling before it is actually working. A 120 amp alternator will take more power than a 35 amp alternator. Air conditioner and such. 
But I can’t answer your original question. 

[MTB98]

10 hours ago, acem said:

It makes no sense that the big Dodge Challenger with a 300 hp engine would get 30 mpg while the little Honda  Civic with 120 hp engine get 34 mpg! 

The actual amount of work or energy needed to move the cars down the road at highway speed isn’t that different between the two. If each car was using the full amount of horsepower they could produce the Dodge would be using way more fuel than the Honda. 

12 hours ago, JaredT said:

If you did the same job with a 1086 or a 4440, the 1086 would use way less fuel.

Nebraska Tractor Tests show them nearly equal in fuel use, the Deere used <1/2 gallon more per hour.  The Deere has a little larger engine and more hydraulic flow. 
Deere test 

 

IH test 

[Lazy WP]

I have been a HUGE supporter of the Nebraska tractor test, but their results and real world data don’t always match. I used to spend way too much time watching them test different tractors instead of studying. Might be part of the reason I didn’t graduate from there. 

[dale560]

1 hour ago, MTB98 said:

The actual amount of work or energy needed to move the cars down the road at highway speed isn’t that different between the two. If each car was using the full amount of horsepower they could produce the Dodge would be using way more fuel than the Honda. 

Nebraska Tractor Tests show them nearly equal in fuel use, the Deere used <1/2 gallon more per hour.  The Deere has a little larger engine and more hydraulic flow. 
Deere test 

 

IH test 

That is the thing. Everybody has warm fuzzie feelings for their chosen brand. And absolute hatred for everything else. When results are actually on paper they are almost identical. Cars trucks tractors all the same. It is always fun reading the big truck sights on fuel economy and power stories

[Big Bud guy]

31 minutes ago, dale560 said:

That is the thing. Everybody has warm fuzzie feelings for their chosen brand. And absolute hatred for everything else. When results are actually on paper they are almost identical. Cars trucks tractors all the same. It is always fun reading the big truck sights on fuel economy and power stories

As related to my initial post in this thread my Big Bud will run 2 days or more on one full tank of fuel.  Must be super efficient??  That being said the only real measurable fuel difference I’ve seen is on our combines and sprayers.  Both sprayers have the same size fuel tank but one has command drive meaning the engine only runs as fast as it needs to. Most of the time I’m going down the field at 1,500 rpms.  The other sprayer has to be run at full throttle.  The different between the two is I get 320 or more acres sprayed with the one with Command drive on a full tank of fuel.  Combines are the same deal.  Our class 11s have the same size fuel tank as our old class 8.  At the end of the day there would be roughly the same amount of fuel and def left in both combines.  Yet the class 11s cut about 10 more acres per hour per machine.  Difference is the engines.  Newer ones run only at 1,900 instead of 2,200

[Binderoid]

How big is the tank and how long is the "day"?  Id like GPH, please

[acem]

13 hours ago, MTB98 said:

The actual amount of work or energy needed to move the cars down the road at highway speed isn’t that different between the two. If each car was using the full amount of horsepower they could produce the Dodge would be using way more fuel than the Honda. 

Its much more complicated. Here's a some more examples.

Dad bought a new GMC pickup in 1970. 1/2 ton, 350. 4bbl, auto, no AC. Very good truck except it got about 8 MPG. No problem until the Oil Crisis hit. Then the price jumped and gas shortages became common. In 75? He bought a 73 Dodge 1/2 ton, slant 6, three on the tree, no AC. Got 18 MPG driving the same.

The trucks were basically the same except for the engine and transmission and one burned twice the gas doing the same job.

Another example is my wife's favorite car. The same basic Metro was available with  different drivetrain options. I'll stick to all the same year, body and engine displacement to keep it as similar as possible. All MPG from the EPA and I can verify they are accurate.

Basic Metro 1L three cylinders auto transmission 35 MPG

Basic Metro 1L three cylinders 5 speed 45 MPG

XFI Metro 1L three cylinders 5 speed 52 MPG

The basic metro 5 speed looses 10 mpg with the auto transmission but gains 7 MPG in XFI configuration. The basic cars are the same but the devil is in the details. 

XFI has various differences including, weight reduction (less soundproofing, no right hand mirror [also reduces drag], and various other things), higher speed overdrive and engine changes (one compression ring, different camshaft, etc).

As you can see little things can make a big difference even when they seem insignificant. The combination of different things can be synergistic or antagonistic.

It really is complicated.

[Eason]

I don't put much faith in Nebraska test. Look at the test for a 4020 and a 856. The test show a 4020 will out pull a 856. We all know the truth on that one!

[JaredT]

Nebraska Tractor Tests show them nearly equal in fuel use, the Deere used <1/2 gallon more per hour. The Deere has a little larger engine and more hydraulic flow. 

 

I can guarantee if you had an IH 400 series engine with same load behind it as a Deere of the same size and age, the fuel use is more than  2 gallon an hour more on the Deere. I realize Nebraska tests didnt come up with that, but real world will tell you that.  I am not knocking the Deere, I realize they are good too. My point is equal HP, why is the IH more fuel efficient? Is it injectors, Pump?, cam? Airflow in the head? I dont know enough about engines, I am curious 

[acem]

Horsepower numbers can be deceiving. 

 

[yellowrosefarm]

My Doncaster built 485 uses way less fuel running a 7' rotary cutter than my JD 2355.  More than just the HP difference should account for. 

[Big Bud guy]

3 hours ago, Eason said:

I don't put much faith in Nebraska test. Look at the test for a 4020 and a 856. The test show a 4020 will out pull a 856. We all know the truth on that one!

Drawbar tests can be manipulated.  Take a closer look at the ballast and tires.  The PTO tests though I don’t see how that can be much different from “real” world results.