Wondering about horsepower.

[DeereMann]

Briggs and Stratton is publishing their peak (gross) torque curves @ rpm.

And yes, they were all 'cheating' in terms of overstating horsepower before, but it kept getting worse. I could have cared less, they just sent me some money I never asked for.

For a stoichiometric spark ignited engine, it really only matters what the displacement & maximum rpm is. Except when folks like Ford start playing around with stratified charge GDI and high turbo boost! But we're only talking about smaller engines here.

Remember horsepower/torque is governed by various & sundry 'standards' that some do or do not adhere to, and they can be published at 'other' conditions. i.e. - high atmospheric pressure & cold temperature to inflate output values.

 

[murphy1244]

My small engines use CC's as the size of engine. Never seen Torque ads

 

[Buggs67]

LD1 Wrote QUOTE
"or even better a full torque/hp curve." This is what I'd like to see

"People like to reference "down low torque" or "more torque at lower rpm", which is correct. But More torque at lower RPM also means more HP at them lower RPM." Like my Jeep straight 6.


"I do wish they would at least give the torque @ operating RPM. Cause at least that way you can figure the HP."

You answered a few questions. I was thinking more about what RPM to operate my tractor at for backhoe operation. Since this is purely by hydraulic pressure from the pump, I thought that setting the engine at where it makes it's maximum torque would be most efficient/quiet and good for engine longevity. I don't need to do more work faster in this mode (I can hardly keep up with the hoe as it is).

I don't have enough knowledge about diesels to know what's best for them. With gas engines I always thought it was best to keep them rev'ing, not lug the engine but don't over rev/beat it.

BTW Thanks for the info/education.

 

[Buggs67]

Also, I had to replace the 10HP Tecumpseh on my snowthrower and it was hard to convert cuz they rate the new engines by torque power and CC. And they are now all OHV engines. The 216 seemed too small for my machine and the 346 too large. Well now my snowblower has a larger engine than my small quad:thumbsup:

 

[KennyG]

The HP ratings are probably correct with today's propensity to sue.I wonder if the lawn tractors need a lot of power because of the inefficient transmissions and drives.I sometimes use a Craftsman with a 26 hp Kohler and a 52 inch deck. It's Okay but I can mow at least 3 times as much with my 24 hp 2320 with 62D deck in the same time.

 

[Baby Grand]

It seems like the new gas engines are fine until you load them to the point that the speed drops below governed speed and the torque just drops off like a stone and you have to slow down and let the engine speed back up and start making torque, again. With the older machines, they seem to be much more stubborn about dropping rpms. There's still lots of torque a few hundred rpms below the governed speed - it almost seems like there's a little more torque down there. The new ones just don't grunt like the old ones.