Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

Does anyone know why the new engines does not have HP raing anymore?  It only indicates how many CC.

Knowing just the Cibic Centimeters is almost useless to me.   A two liters race engine is complete different from a 2 liters engine used on the street.  I never pay too much attention on the actual size but the HP rating when buying a car.  

The problem with rating by displacement is that it is just the volume of displacement. There are many factors that effect the actual power such as Exhaust, Carb., valve & Ign. timing. Granted there are not too many options available to hop up the power of small engines like there are in the automotive sector so you are pretty much stuck with what you get.

I'm fine with them rating by torque, but not if they're just going to continue to make up numbers. The upside to listing displacement is that you really can't fudge it. Cylinder diameter is easy to measure, as is stroke. It at least provides one method to compare "theoretical" performance. But it would be nice to show some measure of the engine's actual performance. You could build a 400cc engine that makes 2 hp if you wanted to.

It is funny, though. I think of temperature in F, distances in inches/miles, etc. But I consider engine displacement in cc's/liters, not cubic inches.

They can't make up torque numbers, and if you think they are, you can measure it yourself. It's the ONLY useful measurement of power for small engines.

Bill_H wrote:
How would you go about measuring torque? It would seem no easier to measure, and therefore no harder to fake, than power. If you have the ability to measure the torque, then getting the RPM's should be easy (tachometers are readily available). And at that point determining the horsepower is a quick calculation away. But measuring the torque does not seem trivial to me, using anything that a "normal" person would have access to.

To New_Yorker's earlier point, sure, it would be cool if Consumer Reports measured the torque of each engine. But they certainly don't put every car on a dynamometer to measure its power (nor, for that matter, do performance-oriented magazines, when testing non-modified cars). And for a car you can just strap the whole car onto the machine, and go (oversimplifying a bit, of course). For OPE, you would likely need to remove the engine from each machine to try and test it. That's not going to happen anytime soon. So it would appear that we're stuck going by what the manufacturers tell us.

Bill_H wrote:
And of course, if we're being technical, torque isn't a measure of power at all (j/k , I know what you mean)

I want to know how much "power" the augers have in terms of ability to hold it's rotation speed Under extreme conditions. Including the impeler. Remember, belts clutches etc. they all " eat" power! Including non hydro drive

JoelKlein wrote:

Yep, there's a lot more to performance than engine power.  Centrifugal (rotating) mass can eat power, but can also allow the machine to lug through bits of heavy stuff better (the flywheel effect).  As for snowblowers, there's impeller design/speed, as well as other factors determining ultimate performance.

Things like valve timing and overlap, bore/stroke ratio, flywheel specs, etc. will determine the engine's internal lugging ability, whereas external components can determine overall lugging ability.

The old Allis Chalmers WD45 tractors were quite popular in their day (~60 years ago).  The diesel model utilized a 230c.i. (3.8L) six-cylinder engine that was tested at 30hp at the drawbar, 259lb-ft torque at 1169rpm - the gasoline model was a 226c.i. four-cylinder tested at 38hp and 288lb-ft torque at 847rpm. The HP numbers don't look impressive for the engine size, but the engines had fantastic lugging ability which was important when using ground-engaging attachments.  My brother still uses one on the farm.