Oil & Fuel Diesel vs Gas Engines

TresCrows · Feb 19, 2001

Sorry, forgot something, the Kubota BX does not have 14 guage stamped steel frame, it is in fact a 3/8 inch welded steel plate full length ladder type. Sorry for the extra post, just wanted to correct any misconceptions, urban legends. JR

Anonymous Poster · Feb 19, 2001

Tractor Horsepower Story

http://www.andrew.cmu.edu/user/kb13/ans_hp.htm

paccorti · Feb 19, 2001

Oh I don't think the discussion was all that hot /w3tcompact/icons/smile.gif.

I was one of the commentators on the jplan tractor board about horsepower. I think we should be careful to not put torque on some pedestal as being more important than horsepower. The two are always related. If you tell me the torque (or horsepower) at a given RPM you can always derive the other. The two concepts are intricately linked together by simple multiplication. The concept occurs over and over again in engineering.

If I apply a voltage to a circuit I will push some current (amperage) through. If I double the voltage I will double the amperage. Is voltage more important than amperage?

Ask yourself this, if you could double your torque but perform any given job at half the speed would you be happy? Horsepower is a better measure of an engine's ability because it accounts for the concept of time. Give me a high horsepower engine and I'll gear it down and give you tons of torque.

I'm not surprised that the BX is more capable (in some respects) than a lawn and garden tractor. Better traction and lower gearing will easily explain the differences.

Peter

toddler · Feb 19, 2001

I'm with you on most of that Peter, work over time being the issue, but the engine differences are more than you or most of these posts give credit for. Standard gas lawnmower engines are designed to cut the lawn (~2hrs) 20-30 times a year for 3-5 years. That's a life expectancy of 300 hours. That's why the "industrial" gas generators use OHV and cast iron sleeves. Running 30hrs a week, the standard gas engine would only last 2-3months. The OHV engines last longer, a few thousand hours, but it is expected that they'll only be under load a fraction of the time they run. For example when I run my chop saw for 3 seconds, 30x an hour for an hour. The engine/generator is under load 90 seconds per hour. The engines in the BX series are designed to run PTO implements, such as a tiller, under fairly continuous load, for hours on end. Given that, you're not being fair saying since HP is equal, capability differences are due to gearing. In reality, it's durability people pay for here. If you could swap a Honda or Kawasaki gas engine into the BX, it would probably perform at about the same level, but only for a few hours.
Todd

PS) How come nobody was impressed that Rick Jay's B2910 has a 1500 cu inch engine. My 2710 only has 81.5inches of displacement. I want to know how you got that yacht engine to fit in your tractor Rick.
-Todd

LarryT · Feb 19, 2001

Good answer Toddler! Now, I've been considering buying a JD Gator and am somewhat torn between the gas and diesel version. While I don't expect the Gator operate under load a very high percentage of the time, I still think the overall longevity issue is valid. Guess I'll have to fork over the big bucks for a diesel version which, of course, they only put in the most expensive version.

Larry...

JATO_RaT · Feb 19, 2001

If I apply a voltage to a circuit I will push some current (amperage) through. If I double the voltage I will double the amperage. Is voltage more important than amperage?

Peter, this is not quite true. Given the load (resistance) stays the same, by doubling the voltage, the current (amperage) is cut in half. Take a look at the dual voltage motors found on some tablesaws and air compressors and you will notice the amps for the 240V hookup is exactly half of the 120V nameplate rating. This again bears in mind that the load stays the same for the 2 voltages and heat is not taken into consideration. Rat...

JATO_RaT · Feb 19, 2001

Pat, I'm not sure I understand your torque estimates for the Ford or Chevy gas engines. I have yet to see a stock 460 or 454 even come close to the torque values of the Cummins or PowerStroke. Each of which in their stock configurations are over 500 ft lbs. I know that the stock gas engines are not that high. When it comes to the semi truck engines, we may be seeing only 300 to 400 HP but the torque values are around 1600 FT. LBS. Rat...

Anonymous Poster · Feb 20, 2001

I believe the manufacturers like John Deere and Polaris installed "diesel engines" in the Gator's and ATV's more for the farmer because of the "availability" of existing diesel fuel on the farm.

Diesel fuel efficiency and durability over gasoline engines are a given... but the advanced technology of gasoline engines over the past 25 years has resulted in higher efficiency and durability of them as well...(4 cylinder 2 liter gas engines approaching 300 hp, 40 mpg , 200,000+ miles - unheard of a few years back)

Mostly government programs and regulations put these companies on notice to clean up their engines... so in the process... they designed the cleaner engine (both gas & diesel) with some nice side effects of better fuel economy, and a stronger (both horsepower & torque) and more durable engine vio'la...

putty340 · Feb 20, 2001

Give me a diesel engine any day when it comes to longevity.The gas engines they are putting in cars nowadays are impressive,but if you were to put the same technology into a diesel it would last even that much longer; roller rockers,roller lifters,roller camshafts. The reason diesels last longer is everything is bigger,but more importantly they produce way more working power(torque) at a much lower RPM. Take a gas motor and gear it down,you could produce the same effect at the rear wheels,but you are going to be spinning your motor 3000 RPM more everywhere! that makes for a lot of wear. Diesels are stinky though./w3tcompact/icons/laugh.gif

toddler · Feb 20, 2001

Larry,
I was comparing the gas engines in garden tractors to the Kubota's 3cylinder diesel. John Miller, III makes a valid point about why JD probably offers diesel in the Gator. I don't know, but I doubt the Gator has a one or two cylinder OHV engine like in my "commercial duty" Generac generator, or a JD lawn tractor. It's probably closer to what they put in ATV's, and might be the better choice for you. You'd have a hard time convincing most of us to buy a diesel car, other than some of those Mercedes Turbo-diesels I can't afford, but we'd agree the diesel in my brother in law's F350 is a good choice, since he pulls a trailer with it.

A high reving, well cooled gas engine might be better in the Gator, since it probably won't spend a lot of time pulling a trailer up a hill, and might have a faster throttle response. Don't spend more if you don't have to. Drive em and see if there's a difference.

What's the gator for anyway??

Todd