Which has more power, Diesel or gas

Two examples:

Overall I have more HP than a 10 year old (I hope I still do anyhow:). Give me a 6-in long wratchet wrench (gasoneline engine) and give him an 18-inch wratchet wrench (deisel engine). If I can get a nut turning, I am probably going to beat him by a long shot, in terms of how long it takes to get the nut off. For that job, I have more HP of a kind that can do the job and I win. BUT ... If I can't build enough power with my short wrench to get the nut started turning off, all that "potential" HP isn't doing me any good. But for this job, the 10-year old with the long wrench can build enough power (in the form of torque) to get the nut turning. For that job, he wins.

Another example. My bosses BMW Z has more HP than my 7.3L Powerstroke, but I doubt he could pull my 5th wheel trailer with it. He'd probably be OK with it at 80 mph, but getting from 0 to 60 mph may be a problem for him; not to mention what happens when going up hills. For towing a heavy load, a diesel is generally better.

One other thing to consider. There is a lot of engineering between the engine and the wheels that contributes to the work that a machine can do. Main considerations are gearing and the weight of the machine. I have a Ford 841 - only about 45 HP, but in low gear I'd be hard pressed to put enough weight on the machine to gain enough traction to keep the wheels from turning. They just keep turning until they've buried themselves in the dirt.

A diesel runs with an unthrottled intake and is controlled by varying the fuel to air ratio whereas a gas engine is controlled by throttling the intake and varying the air flow at almost constant fuel-air ratio. The specific fuel consumption is lower on a diesel of the same horsepower versus a spark ignition engine.

But a horsepower is 550 ft-lb/sec and how ever you make it it's the same ammount of power.

I can remember when we started seeing our first diesel tractors. We loved them particularly of jobs like hay baling, haybines, etc. One I remember in particular was our Farmall 300 gas, ran the 9' haybine ok, or so we thought until we got a diesel. The 300 would drag down a bit and when the governors hit, it would break a shear bolt. This would happen 5-6 times per day. Later I ran that same haybine with two different diesels, and never broke a shear bolt.

My 12 year old son likely has more power than I when it comes to moving 10 pounds. He could grab 10 pounds and run faster than I could to cross a finish line. I would have more power if we had to move 100 pounds. I would likely cross the finish line first.
Almost like compareing oranges and apples.
Sort of like having an oxen and a horse pulling a paticular plow. At a point they will be able to pull the plow at a particular speed and be neck and neck. Then either make the plow larger or smaller and one or the other will have the advantage.
Consider a diesel a muscle man and a gas engine an thin athlete that can run fast.
Which as more power as you can see it in different situations.

Reason being is the rider mower's engine manufacturer will have specced that '16 hp out as probbaly the max hp that engine could make.. at max ( perhaps not rated ) rpm, no accessories.. possibly even a special fuel and oil, and carb settings... and that power rating wil be taken right befor ethe engine detonates.

Now.. on a tractor.. that 16hp .. may be drawbar, or pto.. or net engine... that's what you got to compair.

Weight becomes a factor too. A 25 hp rider mower from a box store likely have 1/2 or 1/4 the DB hp od a heavier but lower hp scut.. mainly due to weight / traction issues.. etc.

Soundguy

Diesel's by nature have really interesting governors and can temporarily exceed their hp rating for brief periods even when wide open. A gas engine can't do anything to increase its output when wide open so they behave much differently.

Now, that will bring a sad tear to your eye. :>)

Allan