Still understanding the implication of different tractor specs

GeoHorn

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That would be true for a spark engine where a stochiometric mixture is needed. But a diesel only injects the fuel it needs, usually running lean.
I’m not sure that’s the way to view it. The amount of fuel injected would be proportional to the amount of power requested by the operator/throttle. The amount of air packed into the cylinder would vary based upon the speed developed by the engine which, in-turn, pushes exhaust gases out to drive the turbo. So increased fuel injected will produce increased turbo-power resulting in increased air sufficient to match up with the amount of fuel. (Often evidenced by that little black “puff” which occurs when the throttle is first jammed further-open…and which clears up as addt’l air is pumped into the cyl by the turbo.)
 

PoTreeBoy

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I’m not sure that’s the way to view it. The amount of fuel injected would be proportional to the amount of power requested by the operator/throttle. The amount of air packed into the cylinder would vary based upon the speed developed by the engine which, in-turn, pushes exhaust gases out to drive the turbo. So increased fuel injected will produce increased turbo-power resulting in increased air sufficient to match up with the amount of fuel. (Often evidenced by that little black “puff” which occurs when the throttle is first jammed further-open…and which clears up as addt’l air is pumped into the cyl by the turbo.)
Agree, but I was trying to address NA also.
 

Dieseldonato

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You've been given plenty of advice. It's you know you may need 50 pto hp to power your 12 foot mower.(once you get it) I've said quite a few times I mowed with a 12 foot progressive finish mower behind a 75hp tractor. I realistically wouldn't have wanted much less pto hp. In an 8 hr mowing shift it was nearly out of fuel. Usually below 1/4 tank. It's time you go run a few of these machines and see how they will work for you.
 

PoTreeBoy

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You mentioned OP down your way means "Over Proof..."

Up my way NA means "Not Applicable..." :ROFLMAO:

Natural Aspiration?
normally aspirated or naturally aspirated

OP wasn't me. It was, well, original poster
 
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Marlon

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A paper spec is a paper spec. Park your butt in each machine. Use them for a while. Test all the functions you need to use ie. I won't buy a loader tractor that can't do two functions simultaneously.

See if you can get a demo of each machine to use over a weekend. See how much fuel each one consumes. How comfortable is the operator station - remember you will spend thousands of hours in that seat. Cheap out now and pay for it later.
Well this would be great if it wasn't for COVID and supply chain disruptions, I don't think there is a new M series tractor on any dealership yard in Australia at the moment and I can't even get a delivery date
 
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IanB

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Then why have the turbo charger on the diesel to begin with? If the excess air pushed into the engine is of no use?

Honest question.

Seems logical to me that the extra air is needed for something. If not needed for combustion of extra fuel in a diesel, what is its purpose? How would a turbo charger increase HP output otherwise?
Boost on a diesel engine is based on engine rpm and load, up to the wastegate setting where the excess bleeds off. If low load, then usually no/low boost would be generated, and no/low additional fuel injected to suit. The harder the engine works, the more load on the engine, the more boost is generated, up to the wastegate point, and the more fuel is injected to match the extra air. Most diesel engine's don't have throttle bodies in automobiles, and I would expect don't in tractors either, so they get all the air they need, all of the time even without a turbo. Adding a turbo gives the engine all the air you need, lol.
 

Henro

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(Snip) Most diesel engine's don't have throttle bodies in automobiles, and I would expect don't in tractors either, so they get all the air they need, all of the time even without a turbo. Adding a turbo gives the engine all the air you need, lol.
This is what I am referring to re Posts above. IF without a turbo charger the engine gets all the air it needs, why add the turbo charger? Must be to provide additional air to burn additional fuel (which could not happen otherwise), to make additional power.
 

mcmxi

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Must be to provide additional air to burn additional fuel (which could not happen otherwise), to make additional power.
Yes! Maybe this is obvious but typical atmospheric air at 14.7psi contains a specific amount of moles of oxygen molecules which can be calculated based on the atomic mass of Oxygen. When diesel is burned in the cylinders the amount that can be burned is limited by how much oxygen is available. When you increase the pressure of the air entering the engine you increase the number of moles of oxygen and therefore how much diesel can be burned which increases power output.

Turbos are efficient though, particularly on smaller engines which have smaller rotating parts, less mass etc., resulting in less fuel input compared to a larger normally aspirated engine putting out similar power.
 
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GreensvilleJay

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One consideration in the 'turbo' or 'NOTturbo' tractor is repairs and parts. A 'turbo' engine is more complex, more parts and WILL cost more to repair. Anything 'complicated' costs more to buy ,maintain, and fix.
I'm pretty sure all will agree. The BIG issue is can you get it fixed ? How's the local dealer's mechanics ? can they get the parts? Do they KNOW the engine ?
I know nothing about the tractors/engines in the previous posts but certainly being able to get a busted tractor up and running and back into the fields' NEEDS to be considered. Be interesting to see the 'numbers' dealing with repairs but I bet that'd be closely guarded or dang impossible to find.
While a turbo version may be 1-2 gph more economical, it's USELESS if it's in the shop,waiting for parts,coming 'sometime'.....
 
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mcmxi

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One consideration in the 'turbo' or 'NOTturbo' tractor is repairs and parts. A 'turbo' engine is more complex, more parts and WILL cost more to repair. Anything 'complicated' costs more to buy ,maintain, and fix.
I've owned three cars with turbos, two of which were V6s and had twin turbos. I've owned a truck with a turbo, owned a tractor with a turbo, still have a truck with a turbo and have two tractors with turbos. So that's 10 turbos, hundreds of thousands of miles but not a lot of tractor hours, and I've never had to replace or repair a turbo. They're very well-proven technology, and if you don't abuse them they'll last a long time. Lots of aircraft use turbos too.
 
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Dieseldonato

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I've owned three cars with turbos, two of which were V6s and had twin turbos. I've owned a truck with a turbo, owned a tractor with a turbo, still have a truck with a turbo and have two tractors with turbos. So that's 10 turbos, hundreds of thousands of miles but not a lot of tractor hours, but and I've never had to replace or repair a turbo. They're very well-proven technology, and if you don't abuse them they'll last a long time. Lots of aircraft use turbos too.
You,me and like minded individuals who have owned/ worked on turbo diesels will never win with this crowd.
 
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troverman

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If you search for "Kubota [enter model here] Bid Specifications" you can typically find far more detailed specs published from Kubota. The dealer can also print these out for you, they are several pages long. One spec they include is "gallons per hour at PTO speed." I was considering an M6060 vs the MX6000. Engine HP and PTO HP were fairly similar but they were very different engines...the MX had the venerable V2403 2.4L turbo 4 cylinder and the M6060 had the equally venerable 3.3L turbo 4 cylinder. The M6060 is quite a bit more substantial than the MX, with heavier duty basically everything. Whereas the 2.4L turbo is basically maxed out for power, the 3.3L in the M6060 is near its lowest power output. The larger displacement produces quite a bit more torque, and allows the engine RPM to peak lower. There is also the 540e option on the M6060 for even lower RPM operation. When it was all said and done, I went with the MX6000 because for my delicate flail mowing operation on very steep slopes, I wanted the precise control of HST which is not offered on the M6060.

Regarding turbo fuel consumption, the purpose of the turbo is to allow a smaller engine to make more power than it would otherwise. This is done by packing more air into the cylinders because the turbocharger is pressurizing the air. In turn, this allows the injectors to push more fuel into the cylinders and the resultant combustion explosion is more forceful than it would be under natural aspiration and lower fuel volume. Keep in mind, these are completely modern electronically controlled engines. Pushing more fuel without the added air simply means unburnt fuel which creates soot and wastes fuel. Sensors detect air mass or pressure and send that info to the ECU, which can also calculate load and take input from other sensors to determine how much fuel to inject. These engines use cooled EGR recirculation, and I would assume they do in fact have a throttle plate which is controlled by the ECU to vary the amount of EGR / fresh air mix.

Regarding the reliability of the turbo and ease of repair: at least on the 2.4L engine, the turbo is tiny, easily accessible, and is not intercooled. Instead of the exhaust manifold sending end gases straight to the DPF, it sends them through the hot side turbocharger turbine first, then to the DPF. Spinning the hot side turbine simultaneously via a shaft spins the cold side turbine, which draws air in from the air filter, pressurizes it via the spinning turbine, and discharges it via ducting into the intake manifold on the engine where the charged air is distributed to the cylinders. The turbos are lubricated by engine oil - I haven't looked to see if they are also cooled by coolant. I'm guessing just oil based upon their small size. The worst stress the turbo will suffer is during an active regeneration where excess fuel is sent down the exhaust manifold and through the turbocharger into the DPF. As far as reliability, you can't work on a modern naturally aspirated engine either in terms of the electronics. The NA engine pretty much has all the same sensors and inputs and outputs from the ECU to run the engine. And regarding turbo engine reliability in general, keep in mind all your long haul 18 wheelers, 10-wheeler dump trucks, trash trucks, snow plows, diesel pickups, large construction equipment, etc etc...all use turbos and many of these things go to a million miles or more. Most people don't know, but even these small Kubota diesel engines are built like a heavy truck engine. There is no timing chain or belt - they are direct gear drive for the camshaft, etc. The block and heads are iron - not aluminum. The crankshaft, pistons, valvetrain are all exceptionally heavy duty. I have no concern as to the longevity of my 60HP 2.4L. Somebody was mentioning what likely was the Ford EcoBoost twin turbo V6 engines...those are far lighter duty engines than these Kubota motors. Even the big HD diesel pickup engines are all using aluminum heads (except Cummins).

Conclusion for the OP: The smaller turbo engine will probably use more fuel under PTO speed than the larger NA engine. However, for everything else like transport, loader work, idling...the smaller turbo engine will use less fuel. Keep in mind the larger engined tractor is also a heavier machine, which means more power is used just to move the tractor itself, which also burns more fuel. Kubota HST transmissions are probably the most efficient in the industry and better quality than most. The gear drive shuttles are excellent as well and deliver a little more HP to the PTO.
 

Dieseldonato

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well the turbos on the new Minis are NOT 'proven technology'...2014 went to scrapyard with busted turbo, 30KM on it.
Talking about a mini Cooper? They are know for bad turbo/superchargers. And we're not talking about a gas car. We're talking about diesel engines. Which have been turbo charged since at least the 70s. Pretty sure kubota uses a few mix of manufacturers all of which have outstanding track records. Typically if you puke a turbo, you did something wrong. Now waste gates and vgt actuators do give some grief from time to time but it's not typically an issue. The first half of my career as a diesel mechanic was rebuilding engines, cat cummins, mtu, Isuzu, deere, kubota, yanmar, Perkins ect. High hour engines, 6 to 10k hours would be normal, most still ran fine and was for preventing issues down the road. The turbos were rebuilt, but other then new bearings and sealing rings everything was reused that met spec. They got balanced and off they went for another 6 to 10k hours. Yep sometimes they do crap out. We had a Detroit 60 series come to the shop out of a freight liner, customer claimed it "went wild" for whatever reason he wanted to do the install him self. We found the front oil seal in the turbo had broken and it had cooked oil in the housing and bearings, ie abuse. Didn't let the engine cool off after hard use. Like all the rebuilds we did it had a 4 hr dyno session before being sent back to him. Reman turbo from Detroit, engine fully rebuilt. In the greater scheme of things it was an outlier and the abuse was immediately evident on tear down.
Kubota is nearly legendary for reliability, ie if it was an issue it would be well known. It's just not the issue you seem to think it is, nor is it an overly complex add on, even a vgt turbo it typically the turbo, some piping, intercooler and oil lines, possibly water lines to cool the vgt. No more complex then ac or a heater.
 

mcmxi

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well the turbos on the new Minis are NOT 'proven technology'...2014 went to scrapyard with busted turbo, 30KM on it.
How big is your data set? What was the cause of the failure? As stated, turbo chargers are proven technology in various engines and have been for decades. The first car offered with a a turbo charged diesel engine was introduced by Mercedes in 1978. That's approaching 50 years in automobiles, not to mention more than 100 years in aircraft.

Here's an interesting article.

 
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