torque and HP again

[38racing]

Today I saw 2 ads for 5.5 HP push mowers. Both were the briggs carb on tank engines putting out 3.5 or maybe 3.75 HP. The covers said 5.5 but the sellers did realize it was torque and not HP.

[StarTech]

Depends where ft-lb torque was calculated at. Assuming 3400 rpm then it would be 3.561 hp @ 3600 rpm but if was 3200 rpm then it would be 3.351 hp @ 3600.

HP = T * RPM / 5252

[creia]

I remember when Briggs and others got into some trouble with this about 10 years ago. See the link below about the lawsuit.
http://archive.jsonline.com/business/37181244.html/
Michael

[38racing]

I remember when Briggs and others got into some trouble with this about 10 years ago. See the link below about the lawsuit.
http://archive.jsonline.com/business/37181244.html/
Michael

the crazy part of this is that they switched to specifying torque but of course the HP is just calculated from the torque. So how does that change anything really? Do identical engines always now display same torque? If so then they would display same HP. That was the real issue, Identical engines with different label. So now MTD labels an engine 5.0 torque and sears labels it 5.5 torque. Has anything really changed? The gray area is that each engine has a torque curve and hence HP curve so multiple values do exist for identical engines. They needed to specify at what rpm then would consumer really have been better informed with such detail?

[creia]

...And it is not only internal combustion engines. This confusion (deception?) or otherwise misrepresentation of HP rating extends to electric motors as well. Currently sitting in our garage is my 30 year old Sears Craftsman 16 GAL wet-or-dry shop vac that displays 6.5 HP in big letters. 6.5 HP- REALLY!?
Michael

[KE4AVB]

Especially since 220 vac usually can only operate 5hp max electric motor. Now if you go to 3 ph then there are more powerful motors. I have an air compressor that is rated at 5 hp but the new motor is rated only 3 hp and it still draws the same current at startup. More than my 8Kw surge generator can startup under air load even the generator's has 5.5 Kw running capacity. Now the new is rated as a compressor motor.

Yes the old gasoline small engine hp were all over the place as companies use various ratings and could get by as the engine only had to produce 85% gross of the declared rated power and torque. Now the new SAE J1940 rating requirement that went into effect October 1, 2013 that changed to 95%. SAE (Society of Automotive Engineers) has also stated that the engine manufacturer must disclose the rpm for rating and with the GROSS (SAEJ1995) or NET (SAEJ1349) horsepower. (SAE) J1940 based on gross output testing performed according to SAE J1995 without the air cleaner and muffler. Actual engine power and torque can be lower and affected by accessories (air cleaner, exhaust, charging, cooling, fuel pump, etc.), application, engine speed, ambient operating conditions, (temperature, humidity and altitude) and other factors. This J1940 / J1995 rating provides consistent measurement to customers who may want to control the intake and exhaust features of the engine. Some manufactures like Kohler may only test 10 engines off the assembly line and average the output figures and other use minimum found during such tests. Otherwords some engines maybe as much as 5% than the stated gross output figures just depend how the manufacture arrived at their output numbers and still be legal. It all comes down actually comparing the engines to each other in real life for your particular operation with all the accessories (and manufactures do call air filters and mufflers accessories) in place.

[bgsengine]

(and manufactures do call air filters and mufflers accessories) in place.

these days for a goodly number of manufacturers, those parts are now called "Emissions Components" and legally must be replaced with OEM, or parts that have been *EPA Certified* to replace them......

[KE4AVB]

I know. We are getting to a point where we no longer need mechanics just part replacers and those may become obsolete when everything must go back to factory to get EPA re-certified just for an air filter replacement or the equipment owner have go in once a year for an equipment certification test like some states now do for vehicles. Over in Japan if a car has an oil leak it may be in the shop for over a year just to get it fix as it must be certify 100% leak free after repairs.

The EPA probably would had a nervous breakdown if they know all the mods I did to my 79 Malibu V8 even though I double the fuel economy. Even the city mileage was better than the EPA highway rating for the car. The not many V8s that get 32 mpg highway even today though so under perfect conditions. It actually had a combined mileage of 22.6 mpg. I just can't do those mods now as I can't easily get those parts now because the EPA.