Comparison Gasoline vs. Diesel

[BigBlockHead]

I'm a long time lurker on this site but never posted till now. There seems to be a wealth of knowledge here and I'm curious to get your opinion on why no one is offering a gasoline powered CUT? Would you buy one if it was offered for the same money as a diesel? For $1,000 less? $2,000 less?

Tier IV final emissions regulations go into effect in 2013 for 25-75hp off-road equipment and diesel installations will increase in cost again. How much is it worth to you to have a diesel over gas?

I'm just curious if we're on the verge of a shift away from diesels in smaller tractors or if we'll continue to pay whatever it takes to get one.

 

[SkellCo]

I love the smell of diesel in the morning!

Diesel for me, power and performance.

 

[jonyyuma]

Diesels rule when it comes to pull-power and durability. You will have to buy a oversized lawn mower, if you want gasoline power.It can be over 32 horsepower in gas.They make all kinds just for diversity and choice of the future operators.I really like having a diesel after owning an 8N Ford for years.Jy.

 

[Jay4200]

I'm a long time lurker on this site but never posted till now. There seems to be a wealth of knowledge here and I'm curious to get your opinion on why no one is offering a gasoline powered CUT? Would you buy one if it was offered for the same money as a diesel? For $1,000 less? $2,000 less?

Tier IV final emissions regulations go into effect in 2013 for 25-75hp off-road equipment and diesel installations will increase in cost again. How much is it worth to you to have a diesel over gas?

I'm just curious if we're on the verge of a shift away from diesels in smaller tractors or if we'll continue to pay whatever it takes to get one.

I wouldn't buy a gas powered anything. Simply put, you can't let a gas powered appliance sit with gas in it anymore. I spend WAY too much time as it is draining tanks and cleaning carbs on dirtbikes, mowers, chainsaws, generators, etc. I'd hate to think what a mess a gas tractor would be if it sat for 6 months.

OTOH, if I was using it every day, maybe - although all things being equal, a diesel motor will far outlast a gas one, and gas engine maintenance/repair is more frequent and costly. Of course, fuel usage is much higher with gas, so even though diesel is more expensive, fuel cost is likely lower with a diesel too.

JayC

 

[RobertN]

I used to have one. My old Kabota was a 19hp diesel, about 60ci. My old Farmall-A was about 20hp, about 113ci.

The old Farmall made the same power, and had a flat torque curve. But, to do that, it had to run twice the cubic inches, and much less fuel efficiency. That old Farmall did it at only 1600rpm. But it was big cubic inches. And a heavy crank, and heavy flywheel.

the old Farmalls and JD's can pull as well as the new diesel tractors. But, they are much larger engines that use lots more fuel.

Another example is big trucks. I know of folks that have had late '50's early 60's American LaFrance fire engines for parade. They had huge gas engines that got 2mpg. They would pump a lot of water, but practically had to be attached to a gas pump. Similar engines with diesels got significantly better mileage, soometimes with smaller motors.

I can not imagine going back to a gas engine, even with fuel injection. It would be possible, but would again result in large cubic inch motors to get that broad spectrum flat torque curve.

 

[dave1949]

I wouldn't buy a gas powered anything. Simply put, you can't let a gas powered appliance sit with gas in it anymore. I spend WAY too much time as it is draining tanks and cleaning carbs on dirtbikes, mowers, chainsaws, generators, etc. I'd hate to think what a mess a gas tractor would be if it sat for 6 months.

OTOH, if I was using it every day, maybe - although all things being equal, a diesel motor will far outlast a gas one, and gas engine maintenance/repair is more frequent and costly. Of course, fuel usage is much higher with gas, so even though diesel is more expensive, fuel cost is likely lower with a diesel too.

JayC

Excellent point. Not real sure of my tractor history, but it seems like Kubota 'invented' the modern CUT and sub-CUT, at least for general use in the US market. Have Kubotas always been diesels?

I have put a few hours on older gas tractors (1600 and 1800 Olivers) doing row-crop field work. Never had a chance to run a comparable diesel model to get a side-by-side feel for any differences.

I am happy with my NH/Shibaru diesel engine. I can't think of anything a gas engine would do better for me. For those up north that have to start diesels in very cold weather or worry about gelled fuel, gas might be an advantage, but only a couple days of the year perhaps.
Dave.

 

[Jerry/MT]

I'm a long time lurker on this site but never posted till now. There seems to be a wealth of knowledge here and I'm curious to get your opinion on why no one is offering a gasoline powered CUT? Would you buy one if it was offered for the same money as a diesel? For $1,000 less? $2,000 less?

Tier IV final emissions regulations go into effect in 2013 for 25-75hp off-road equipment and diesel installations will increase in cost again. How much is it worth to you to have a diesel over gas?

I'm just curious if we're on the verge of a shift away from diesels in smaller tractors or if we'll continue to pay whatever it takes to get one.

Back when i was in college(1960 ish) the thermal efficiency of the diesel is about 39% wereas the gas engine was about 28%. This mainly due to the compression ratio (17:1 for a diesel compared to ~8+:1 for spark ignition mainly due to the fuel and the detonation problem plus the fact that the diesel does not throttle the airflow for speed control at part throttlel). So theyare more fuel efficient. It used to be that diesel fuel was really less expensive than gas, especially off-road with no road tax. It still is where I live but the gap has narrowed, and you can't get off road gas here. Their mechanical efficiency I would suspect is about the same with the gas engien slightly better..

The newer gas engine in cars are probably much better than 28% in thermal efficiency nowadays and while there have been big improvements in diesels I don't know if the gap is still the same. Torque is higher for a given displacement as is torque rise. Gas has some safety issue in a farm environment that diesel fuel doesn't. on the other hand, cold weather operation with gas is a lot easier than diesel just because of the fuel properties. However a spark ignition engine specifically for tractor would be designed differently than a car engine and would be more expenive than an old gasser engine. So the cost difference would probably not be that great.

I suspect there is no compelling reason to have a gas powered tractor in the market place and I suspect it's tied to the fuel burn advantage of the diesel engine driven mainly by its higher compression ratio.

 

[RobertN]

I dunno. A gas motor on an old Farmall as I noted above, lasts a long long time. The key, those old gas tractor motors did not rev high. Built to current technology, they would most likely stand up great. But, they would be twice the displacement, and would use more fuel.

OTOH, if I was using it every day, maybe - although all things being equal, a diesel motor will far outlast a gas one, and gas engine maintenance/repair is more frequent and costly. Of course, fuel usage is much higher with gas, so even though diesel is more expensive, fuel cost is likely lower with a diesel too.

 

[jonyyuma]

Marketing being as it is, IF there was a demand for such,there would be modern gas burning tractors. The original Op could convert one, Ie, the modern pulling tractors for sled events> He could even use a Hemi. It is quite a hobby for a lot of builders and contestants.Jy.

 

[Lumberjack1903]

Simply put - there's more BTU's in a gallon of diesel vs a gallon of gas. Diesel = more power & efficiency, bar none.

 

[Nightrain1]

My old ztr was a gas kohler 20 hp and my new ztr is 28 hp perkins diesel. I have cut my fuel consumption in half plus a bunch more torque. I never was a fan of diesels until I seen firsthand how much more efficient they are. One day I will have a little turbo diesel car getting 45+ mpg also.

 

[TripleR]

No thanks, I grew up operating gas tractors and we still have three, but for power and fuel efficiency, you just can't beat a diesel; in my opinion anyway.

 

[Gittyup]

If you buy a diesel for fuel efficiency alone, you haven't done the math. The price difference will take years and years before you save enough fuel to justify the higher purchase price. Now you won't have to fill up as often, and there is no doubt that you get more working power with the diesel. Don't think I'd want a true tractor that wasn't diesel. But, it has very little to do with fuel economy.

In a garden tractor, I prefer gas. Start it; let it run for a minute or two, and go to work. Can't really do that with a diesel. And I like the quietness of a gasser too. Yeah, the new gas additives are a pain. I wish all gassers would switch to fuel injection for that reason. But, if used regularly, carburated gas works just fine. And properly cared for, a gasser will last just about as long as you'd ever need it to.

 

[PoorMansCat]

IF the modern gasoline technology makes it into the CUT market, I think it will be a strong seller.
Modern gasoline engines using computer controls and direct injection are creating more hp and a broader torque curve than ever before. Couple that with a small high efficiency turbocharger and you have a good combo for a CUT.
As much as we don't want it, the diesels are fixing to show up with ECU's, DEF tanks, NAC, SCR, etc.... not only is it going to complicate the every day operation of the tractor, it will increase operation and maintenance costs and increase initial purchase costs..
Rather than gasoline, I would opt for a Natural Gas or Propane engine tractor.

 

[wolc123]

One area I still give the edge to gas is extreme cold weather operation. I use a gas tractor and a diesel for snow removal. When it is real cold, and I dont have time to plug in the diesel's block heater for an hour or so, that old gas tractor will fire right up on the first turn or two of the engine, and can be put right to work without much of a "warmup". There was also a time, not long ago, when diesel cost so much more than gas, that I could get work done cheaper with gas in spite of poorer fuel economy.

 

[gengine]

I've got a '69 massey 165 with a perkins diesel. That thing starts right up everytime, and has never had ether since I have owned it. It's only been between -20 and +10 ferenheit for the last month. I would have a hard time buying a gasser, the extra torque you get from a diesel is well worth it. The extra cost in my eyes outways the pain of a gasser. The lower torque of a diesel for when your really taxing the motor, a diesel keeps running, while the gasser dies.

 

[Soundguy]

cub cadet sold a gas engine large scut / small cut in the late 90's...

soundguy

 

[NIXON]

cub cadet sold a gas engine large scut / small cut in the late 90's...

soundguy

Just curious,but how'd that work out for them ?

 

[Mace Canute]

If you buy a diesel for fuel efficiency alone, you haven't done the math. The price difference will take years and years before you save enough fuel to justify the higher purchase price. Now you won't have to fill up as often, and there is no doubt that you get more working power with the diesel. Don't think I'd want a true tractor that wasn't diesel. But, it has very little to do with fuel economy.

In a garden tractor, I prefer gas. Start it; let it run for a minute or two, and go to work. Can't really do that with a diesel. And I like the quietness of a gasser too. Yeah, the new gas additives are a pain. I wish all gassers would switch to fuel injection for that reason. But, if used regularly, carburated gas works just fine. And properly cared for, a gasser will last just about as long as you'd ever need it to.

I think you've hit the nail on the head.:thumbsup:

 

[RobertN]

Wasn't that loosely based on the old Farmall Cub? Or am I thinking of something different? I know the Cub in modified version, and the Farmall-a(-100) made it to about '80.

cub cadet sold a gas engine large scut / small cut in the late 90's...

soundguy