Tractor horsepower compared to vehicle HP?

how does Tractor horsepower compare to vehicle HP? I am seeing all these high cubic inch tractors, (which have gobs of torque) have miniscule horsepower ratings (Oliver 770 diesel rated at 46 hp :headscratch And why cant I build a tractor out of a Chevy 292 that would outpull most tractors (by hp rating)?

Much lower RPM.

Duty cycle is one thing, tractor 46 HP is hard pullling at slow speed all day long non stop at low RPM

Automotive is usually higher RPM, more air flow (cooling)

292 Chev? Seems to me the industrial version of that engine with governor was used in MF combines. I don't think it made the same power as the truck version.

Torque curve,lower RPM,longer strokes.....Lots more to it than just 'rated horsepower.A V8 will have to be kept wound up to get any power out of it.I have an F12 with a (100 horse) 2.8 L V6,and
an original F12. Believe it or not,the original 12 HP F12 engine will always out pull the V6.

A 292 was rated st 95 hp in a gleaner F
combine and about 150 in a truck....but
rated at 4800 rpm in the truck and 2400 rpm
in the combine. Torque peak was close to
peak rpm in the combine, thus the engine
could power through slugs without losing
too many rpms.

Ben

Engine HP versus drawbar HP
Engine HP is often 3 times drawbar HP on the same machine

(quoted from post at 16:29:48 08/07/22) how does Tractor horsepower compare to vehicle HP? I am seeing all these high cubic inch tractors, (which have gobs of torque) have miniscule horsepower ratings (Oliver 770 diesel rated at 46 hp :headscratch And why cant I build a tractor out of a Chevy 292 that would outpull most tractors (by hp rating)?

Click to expand...

his may help you see part of it.
HP=(torque X RPM)/5252
You can get the HP with rpm or torque and in tractors it is by low rpm and high torque.

Tractors are designed to run at max torque. Cars run at max hp. two very different things here as you dont have to accelerate up an expressway ramp and have to merge.... with a tractor. You dont need high speed with a tractor. You need a WHOLE LOT of pulling power that a Car does not need. SO... very low gears, max torque,, and no excess rpms that could double hp but not double torque...

I had a new 66 ford car with a 289 v8 Advertised rating of 200 hp. in the book it stated that the engine had 200 brake hp and 50 torque hp. That seems to me to
be an example what the other replies are talking about.

Power (horsepower or watts - it's just a different way of saying the same thing) is the measure of the work capacity of an engine. Technically an engine only produces torque and motion
(revolutions per minute) and it takes the combination of these two things to do any work - either one by itself is worthless. So, power is defined as torque times rpm. People talk about
torque and power like they're two different things but power is simply torque being delivered at some rate. Torque with no motion won't accomplish any work so talking about an engine's
torque rating by itself doesn't tell you anything about the work capacity of the engine.

As was pointed out earlier the duty cycle of a road vehicle's engine is very different than that of a tractor or industrial engine. A car or pickup engine is asked to produce peak power
for seconds at a time, not hours. So, the automotive engine can achieve high power with a relatively small displacement and make up for the lesser torque by spinning the engine faster and
gearing down more. The tractor engine is asked to produce peak power all day long so in the interest of increased engine longevity, reliability, and efficiency it only runs at 2000 or so
rpm. To get the required power at this slow engine speed naturally requires greater engine torque but the important thing to keep in mind that it is the power rating alone that determines
the engine's work capacity.

(quoted from post at 13:29:48 08/07/22) how does Tractor horsepower compare to vehicle HP? I am seeing all these high cubic inch tractors, (which have gobs of torque) have miniscule horsepower ratings (Oliver 770 diesel rated at 46 hp :headscratch And why cant I build a tractor out of a Chevy 292 that would outpull most tractors (by hp rating)?

Click to expand...

You could, but you would probably run into problems with the engine overheating, and for sure the engine would not last very long.

Road-going vehicles tend to follow an "accelerate, coast, accelerate, cost" use pattern. Even at a steady speed, it only takes a fraction of the engine's HP to keep the vehicle moving.

A tractor on the other hand, you can be using most of the tractor engine's HP continuously for hours on end.

This is really only comparing a passenger vehicle to a tractor. A road tractor is built much more like a farm tractor, with HUGE engines making seemingly low HP output, because of the way they are used. They are expected to pull heavy loads day in and day out for hundreds of thousands of miles between overhauls.

(quoted from post at 16:29:48 08/07/22) how does Tractor horsepower compare to vehicle HP? I am seeing all these high cubic inch tractors, (which have gobs of torque) have miniscule horsepower ratings (Oliver 770 diesel rated at 46 hp :headscratch And why cant I build a tractor out of a Chevy 292 that would outpull most tractors (by hp rating)?

Click to expand...

1 HP is 1 HP no matter if it is electric, gas turbine , water wheel , two or four stroke/gas or diesel , steam or a real live horse .

Well, that was why I picked a Chevy 292, it is a "workhorse" of an engine.

The horsepower of a tractor is measured at the PTO, or drawbar. The horsepower of a car engine is measured at the crankshaft. If you would measure the horsepower of ANY tractor engine at the crankshaft, there would be a large increase in horsepower.

For instance, when I attended auto mechanics school, I was driving a 1060 Chevy with the 283 engine and power glide transmission. I had made a few modifications to the 283 and it really did run pretty good.

The school had a floor dynamometer. Drive the car onto the rollers, strap it down good, and then see how well it performed and how much horsepower was getting to the ground. In this case, I knew the 283 had a factory horsepower rating of 195, but the best I could do on the dynamometer was only 60 horsepower.