Niche segment oppurtunity

[2manyrocks]

Savings offset by fuel use and lack of torque and motor durability.

HP isn't the key factor in a machine used for plowing or mowing.

The gravely L was rated at less HP than the later models with higher HP Koehler engines that operated at higher RPM. Some are of the opinion that the lower HP L was easier to work with than the later models with more HP.

 

[jmc]

HP is HP is HP. It doesn't matter what produces it.

It's the torque curve that matters. HP is usually reported as maximum HP, which is THE sweet spot on the torque curve. A powerful, peaky engine could be whimpy above or below its sweet spot.

 

[jyoutz]

Gasoline tractors used to be more commonplace when gas prices were .39 gallon. Then the market shifted to diesels mainly because they just are more efficient to run for farming operations. Diesels also tend to be more durable because the diesel tends to lube the cylinder walls.

I'm not sure that all the price increase over 25hp is due to HP alone. There are emissions requirements once they go over 25hp.

Does any manufacturer actually sell a gas powered tractor these days?

I’m not aware of any gas powered CUTs of modern manufacture.

 

[MossRoad]

Savings offset by fuel use and lack of torque and motor durability.

HP isn't the key factor in a machine used for plowing or mowing.

The gravely L was rated at less HP than the later models with higher HP Koehler engines that operated at higher RPM. Some are of the opinion that the lower HP L was easier to work with than the later models with more HP.

I'd take torque for plowing but HP for mowing.

 

[4570Man]

I'd take torque for plowing but HP for mowing.

I’ve got a 72” ZT with a 28hp Kubota diesel diesel in it. The diesel burns half the fuel a gas burner will maybe 1/3 the fuel as the newer 30-40 hp gas burners will. As expensive as gas is that’s a pretty big difference. Yes I know diesel cost more but using off-road brings them closer together. The diesel never bogs and just goes without complaining. Without the ability to get more grass out from under the deck faster you could have 100 hp and it wouldn’t help anything.

 

[MossRoad]

Torque is the ability to do work, while horsepower is the speed at which you can do the work.

A machine with high torque and low horsepower does not make a good mower.

I realize everything has to have a balance, however, when talking strictly about torque and HP, fuel consumption is not part of the equation. Torque and HP are.

If you take a care with 200 foot pounds of torque and 100 HP and put it in a race with a car with 200 HP and 100 foot pounds of torque, the latter car will win the race every time. It'll also consume more fuel.

Cutting the lawn is a speed race, not a pulling contest.

 

[RSR]

As a mechanical engineer, I always find these conversations somewhat entertaining due to common misconceptions.

As mentioned earlier, Hp=Hp=Hp. Horsepower is (expressed in a simple manner) the product of torque and angular velocity (i.e., speed)

Where individuals often go awry is assuming the engine characteristics (e.g., diesel vs gas, which have very different torque and power curves as a function of rpm) determine the performance of the system.

For example, how well you can mow is determined by whether you have a diesel or gas engine. This is not true. This is why tractors, mowers, etc. have gears. Gearing either increases rpm at the loss of torque, or vice versa. At constant power output (e.g., while plowing a field) with proper gearing you can get whatever torque or speed you want. This is why tractors have gears.

If you don't believe this, take apart a cheap hand held power screw driver. It uses a tiny motor that runs at a speed on the order of 1,000 rpm. They have such low torque that you can easily stop the motor shaft just by pinching it between your fingers. BUT, it then uses a planetary gear system with a gear ratio of around 100:1, which correspondingly increases the torque, while decreasing the rpm's. The result? You can drive a screw with a little tiny hobby-type motor.

 

[Anomic]

In regards to the tq and hp curves. On my gear drive unit it is nice to be able to set the hand throttle at 1000rpm select a gear then use the foot throttle to be able to adjust the speed between 1000 and 2300rpm. However with our hypothetical 40hp gas powered CUT having a modern hydro transmission couldnt you just run it at rated hp (and torque) the entire time and use the hydro to adjust speed? It seems that low rpm torque matters much less with a hydro but I have not used one much so correct me if I’m wrong.

 

[Anomic]

Savings offset by fuel use and lack of torque and motor durability.
.

If you have better numbers let me know but for comparison I found my diesel
Is about 1.75gph under load. My personal experience and based on forums for a 35-40hp carberated gas is about 2gph hitting the governor the whole time. I hear the newer efi are a bit better.
Let’s run the numbers for 1000hrs giving the diesel 1.5gph and the gas 2gph

Diesel:
1000hrs x 1.5gph x 5$/gal = 7500$
Gas
1000hrs x 2.0gph x 4$/gal = 8000$

I don’t know those numbers to be exact. My CUT has probably 10-15% of its hours at idle where a diesel will beat a gas at idle. Different warm up protocols.
Another data point based on zero turns again (only application where the exact same machine has the 25hp diesel and 35-40hp gas) diesel guys claim .5gph and gas guys claim 1.5gph if that ratio true it would be the gas would be 3500 more than diesel.

There are alotnof factors but based on rough numbers I don’t think saying paying an extra 5000$ for a diesel to save 500$ of fuel makes sense. If it’s closer to the second example of 3500 maybe.

 

[4570Man]

Torque is the ability to do work, while horsepower is the speed at which you can do the work.

A machine with high torque and low horsepower does not make a good mower.

I realize everything has to have a balance, however, when talking strictly about torque and HP, fuel consumption is not part of the equation. Torque and HP are.

If you take a care with 200 foot pounds of torque and 100 HP and put it in a race with a car with 200 HP and 100 foot pounds of torque, the latter car will win the race every time. It'll also consume more fuel.

Cutting the lawn is a speed race, not a pulling contest.

A lawnmower is a tool where once you have enough power more isn’t necessarily better. My 28hp ZT was built before the emissions regulation existed. If they felt like more power was needed they’d have given it more power. The drive motors on the mower aren’t going to go any faster. The ground smoothnesses usually keeps you off the full potential anyway. The deck drive belt isn’t going to deliver much more power. The deck is already working at its potential. It can’t take in 50 percent more grass than it already is and spit it out. If you wanted to repower the 28 hp diesel with 40 hp and actually do any good with it a complete redesign is needed.