Gallons per hour....

[D7E]

Tractor I'm looking at says...
2.35 gallons per hour @ 100% load.
What does this mean exactly? What is 100% load?
I don't farm for a living, so cost of fuel is a consideration for me.

I'd agree with this because fuel is our smallest input and if we have a machine that does the job well and quickly trouble free fuel is irrelevant....Seeding with 320hp costs about $2 an acre for fuel...!

 

[e.myers]

D7E-
Yeah, that's what I meant. Your expenses are offset, I'm paying to play without generating any income by use of the tool (for now).

 

[roamerr]

OK -- Here's my take:

If you use your tractor for farming or other tasks where it runs for 8 to 12 hours a day then fuel consumption matters. It becomes a significant cost especially in the large tractors that can burn 75 to 90 gallons per day.

If you use your tractor as a hobby or just to bush hog then fuel is minor. Buy the tractor that fits your need.

My two reference tractors are:

a 1979 MF245 (40+ hp) that I can't push a gallon an hour through if I want to. It's been used for 1 acre gardens and 100's of acres of bush hogging. Fuel is not an issue. The cost is in the implements, tires, and stuff I tear up.

a Kubota BX2230. Small so fuel does not matter. I'll be tired before the tank needs refilling...

 

[schmism]

lets step back and look at this from a theoretical standpoint.

in an internal combustion engine work output is directly proportional to fuel input. (lets assume your running at stoichiometric combustion.)

therefore the only way a turbo would help is that you werent burning all the fuel to start with at a given throttle postion. what does that mean? that for a given throttle position (a fixed fuel input rate, and assuming your not already running stoichiometric) then a turbo would help you do more work on that same fuel input. (due to cramming more air in there and getting more complete combustion)

as for comments about "real world experience and turbo's useing more fuel." LIkely a function of a couple of things.

1) you cant run a diesel to lean but gas engines DO NOT like to run lean as such when you add a turbo there is likely some system to add more fuel to keep your EG temps within norm.

2) with the ability to cram more air into a cylinder, one only wants to add more fuel to it to take advantage of the extra air. and as above more fuel = more power and thats what most people are after in the first place.

so yes your now 40hp motor (thanks to the turbo) does use more fuel than the 30hp NA you started with.

BUT the REAL quesion is, does the now turbo 40hp use more fuel than a NA 40hp. ?!?!?


as to the OP

you can also see near 100% load if brushogging or simular were your consantly adjusting your input speed to keep from bogging the motor = near 100% load

or if you run a stationary machine (like a PTO generator) will/can tax the tractor at near 100% load if things are sized right.

 

[brandoro]

My experience, and what I have read, having owned turbo gas and turbo diesel engines/vehicles, a gas engine on boost is terribly hard on fuel because a lot more fuel is injected to keep the engine from running too lean and also to help cool things, fuel is actually added as a coolant. A diesel on boost is all good, you are getting more power from the same amount of fuel because you are getting a more complete burn. The gas turbo, I would be very carefull to keep it from going on boost unless I really needed the power because of the serious increase in fuel used, the turbo diesel I tried to always have on boost because of the improved fuel economy. This was even more noticeable at higher elevations, anything above 4000feet the diesel was not happy until it was on boost. I also discovered that if I could keep the engine running fairly warm it would help the fuel economy too. To this end I would take the fan blade off in the fall and put it behind the seat, even the clutched fan would slow warmup and cool more than needed when driving.
To avoid the next question, I keep track of fuel and mileage on every single tank, sometimes even noting weather conditions like a big headwind or heavy snow on the road.

 

[Mace Canute]

I also discovered that if I could keep the engine running fairly warm it would help the fuel economy too. To this end I would take the fan blade off in the fall and put it behind the seat, even the clutched fan would slow warmup and cool more than needed when driving.

You've hit the proverbial nail on the head there! Running fanless in winter is a very smart move! Most people don't appreciate how much better their engines, especially diesels, run at full operating temperatures and a lot would be surprised at how high a temperature you can run them with no problems.

 

[lawn_king]

I burn a gallon per hour in my 3540 when its under serious load, a little more if im running the ac.

 

[Redneck in training]

Sorry, but this is nonsense. Turbodiesel engines have lower friction/hp, higher HP/weight, both of which are critical factors affecting fuel efficiency in a vehicle application. The most fuel efficient engines on the planet are turbodiesel engines and they have held this status since the 30's.

I second that. Turbos have lover specific fuel consumption. Turbos recover energy from exhaust and use it to cover suction losses in the intake.

 

[patrick_g]

MY Kubota (NA Diesel with 39 HP) can burn a little more than a gal per hour if you work it really hard but that is NOT TYPICAL.

You don't get something for nothing. Fuel consumption is related to work performed (assuming efficiencies are similar between the large and small engine.) A smaller engine, turbo or not, may burn fuel at a slower rate but takes more hours to do the job. The larger HP machine doesn't always burn more fuel per hour but will if you ask it to do work at a rate faster than the little machine.

This last statement (given similar efficiencies) has to be true.

The "basal metabolism" of a diesel burns fuel when it runs whether or not it is doing anything useful. The larger the displacement the greater the basal metabolism. Turbo diesels have a dual personality. At idle or light loading (low turbo boost) their basal metabolism is low like the non-turbo engine BUT when worked hard (significant turbo boost) they produce more power per unit of displacement than non-turbo and typically do it at least as efficiently (fuel consumed per HP-Hour) and sometimes more efficiently.

The chief reason folks get the idea that turbo diesels burn more fuel is because they can BUT while producing more power. Properly operating turbo diesels DO NOT burn more fuel to do the same job and may burn less.

I have a non turbo diesel tractor, Kubota Grand L-4610HSTC with over a thousand hours on the meter. I get by fine without a turbo but would not have "dodged" buying this tractor if it had been turbo as I like turbo diesels.

Pat
Pat

 

[Kyle_in_Tex]

Turbos give you more torque and torque is what gets the work done.

e.meyers, nothing personal, but I think you might be splitting pennies. If you are only going to use your tractor a few times a month for a few hours the fuel costs are negligible. If you really want to save money, find yourself a clean used machine and save thousands.

Low usage would lead me to a NA engine. Nothing likes to sit for a month or more unused.

 

[patrick_g]

Turbos give you more torque and torque is what gets the work done.

e.meyers, nothing personal, but I think you might be splitting pennies. If you are only going to use your tractor a few times a month for a few hours the fuel costs are negligible. If you really want to save money, find yourself a clean used machine and save thousands.

Low usage would lead me to a NA engine. Nothing likes to sit for a month or more unused.

Uh... HP defined as is the rate of doing work. Torque times RPM is HP.
Just because there is torque does not imply there is useful work being done. Consider a torque wrench registering 100 lb-ft but the nut isn't turning.

One mechanical horsepower of 550 foot-pounds per second is equivalent to 745.7 watts. This is HP definition.

If your engine is raising a weight of 550 lbs a distance of one foot each second (or an equivalent combination) then it is delivering one HP. How much torque is produced to accomplish this relates to gearing and such.

I'm not knocking the importance of torque (I like torque) but lets not let our feelings for torque cloud our understanding of HP.

Pat

 

[sunnyside360]

I burn a gallon per hour in my 3540 when its under serious load, a little more if im running the ac.

Here's some more real life data, no theory involved.

I have a JD 3720 w/cab and have records since it was new (2 yrs). It has a turbo and has averaged 0.6 gph mostly running a 72" mmm, 60" rotary cutter or 59" front snow blower. The AC is on 90% of the time. I don't really need the HP but got a heck of a deal on it and have never regretted it.

My JD 4320 w/OS averages 0.85 gph running a 72" rotary cutter, sprayer, backhoe, 84" BB, and/or FEL type of work.

My M8200 Kubota w/cab and turbo averages 1.1 gph running 8' rotary cutter, sickle bar mower, 8' snow plow, and/or FEL type of work.

The tractors are rarely, if ever, under full load.

 

[Kyle_in_Tex]

Uh... HP defined as is the rate of doing work. Torque times RPM is HP.
Just because there is torque does not imply there is useful work being done. Consider a torque wrench registering 100 lb-ft but the nut isn't turning.

One mechanical horsepower of 550 foot-pounds per second is equivalent to 745.7 watts. This is HP definition.

If your engine is raising a weight of 550 lbs a distance of one foot each second (or an equivalent combination) then it is delivering one HP. How much torque is produced to accomplish this relates to gearing and such.

I'm not knocking the importance of torque (I like torque) but lets not let our feelings for torque cloud our understanding of HP.

Pat

Pat, I understand the equation perfectly and you are 100% correct. But, just try mounting a 50 horsepower 250cc 2 stroke motocross engine in your tractor and just see how much "work" it gets done. I guess if you had enough gears to let it wind up.....

 

[ctlguy]

Since they don't test tractors at the university of Nebraska anymore I don't believe in ANY info that the mfg are throwing at us.

Has something changed, as far as I know they still test tractors. It is not required unless selling over 40hp I believe in the great state.

 

[newbury]

search
http://www.tractorbynet.com/forums/oil-fuel-lubricants/139067-how-many-units-diesel-hour.html

 

[Gary Fowler]

After reading this from start to finish, I think everyone is right to the extent that they have stated. NA engines of the same size displacement as TC engines will burn less fuel but only because they have less HP. If you have the same HP in a NA as a TC engine, the TC engine is going to use less fuel when doing the same work because it burns cleaner. .
I have owned NA and TC tractors and never had problems with the TC in a diesel. It is pretty easy to tell a TC diesel engine vs NA by the amount of smoke it is putting out when under heavy load. Black carbon equals unburned or poorly burned fuel. The TC is much more efficient at using the fuel injected to produce HP rather than smoke.
This whole issue aside, the fuel consumption of a CUT should be the least of your concerns. 1 gallon per hour or 2 isnt going to make a major dent in anyones budget. If you can afford a $20K or more tractor that most folks using them for Hobby acres and maybe use 100 hrs per year, 100 gallons of fuel vs 200 isnt a major issue in my opinion. As my old high school principal said when someone asked him how much fuel did his Cadillac use, his answer was "If you have to ask, you cant afford it". I think the same applies to tractors, If you have to be concerned with fuel efficiency between brands,which is minimal, then you likely cant afford the tractor in the first place.

 

[ruralruss]

Turbo charging a diesel and turbo charging a gas engine are fundamentally different because one is throttled (gas engine) and the other (diesel) is not. This is a bit of a oversimplification but in a gas engine the turbo forces more air and gas into the combustion chamber to allow the engine to product more power. In a diesel the turbo helps to negate the pumping loses allowing more of the power created from combustion to be used.

 

[BigD23]

I guess I'm not very scientific...I fill my Kubota's tank when it needs it...Heavy or light useage dictates that.

Don

 

[patrick_g]

Turbo charging a diesel and turbo charging a gas engine are fundamentally different because one is throttled (gas engine) and the other (diesel) is not. This is a bit of a oversimplification but in a gas engine the turbo forces more air and gas into the combustion chamber to allow the engine to product more power. In a diesel the turbo helps to negate the pumping loses allowing more of the power created from combustion to be used.

Said another way... Diesels NA or turbocharged have their air intakes wide open all the time and engine output is controlled by the amount of fuel injected. Inject too much fuel (more than there is air to burn) and you make more smoke not more power. Turbos provide more air so you can inject more fuel and burn it. More air and more fuel means more power.

The harder you work the engine the more exhaust gas there is so the faster you spin the turbo and the more air is pumped in by the turbo so you can burn more fuel... lather rinse repeat until diminishing returns dampen the gains. This gives the turbo diesel a wider dynamic range. At light loads it is approximately equivalent to a NA diesel of similar displacement but when worked harder it gets stronger.

I have had a NA Ford F-250 diesel (1984) and turbo Ford F-250 diesel. (2008) The NA version ran out of umph when I tried to take a slide in cab over camper over 11,000 feet on a steep forest service road. In low gear (auto tranny) with full throttle it slowly came to a stop and I had to back down the twisty mountain road to a place I could turn around.

The next year with a 1997 Dodge/Cumins turbo diesel I went up the same road with a larger much heavier camper with a heavy service body on the truck, extra battery banks of golf cart batts, after market fuel tank etc and it would just about wheelie. Way more power than I needed to go up the steep grade mostly due to the turbo which kept the quantity of air going into the engine relatively constant till 9,000 ft or so in altitude and then performance began to taper off with increased altitude whereas the NA engine starts to lose performance as soon as you get above sea level.

I think turbos are a GREAT THING but my Kubota does fine without.

If the engine was not designed for a turbo than adding one will wear the engine out quicker as the crank bearings and such will be under engineered for the added stresses of more torque and HP.

Pat

 

[patrick_g]

I guess I'm not very scientific...I fill my Kubota's tank when it needs it...Heavy or light useage dictates that.

Don

Don, I don't think I'd stop using my tractor if it used 2 gal per hour instead of 1.

I'd just fill it when it got low, like you.

Pat