On Sat, 10 Oct 2009 19:41:38 -0500, Steve Barker
wrote:

wrote:
On Sat, 10 Oct 2009 12:20:17 -0700 (PDT), ransley
wrote:

On Oct 10, 10:57 am, Van Chocstraw
wrote:
Worn Out Retread wrote:
I am looking for a new snow blower and have discovered that the power
rating of the engines are no longer in "Horse Power" but in "Foot
Pounds" if given at all. Sometimes all that is given is the CC's of the
engine.
Even the people selling these machines don't know what the "Horse Power"
ratings are so that old geezers like myself can understand what is going
on. Does anyone have any general rules regarding the conversion of Foot
Pounds or CC's to Horse Power?
They are just trying to pull one over on us by frigging up standard
ratings in the US.
CC's equate more to Cubic Inches. Foot pounds equate to horsepower.
Multiply horsepower by 33,000 to get foot pounds.
It's just another crooked business tactic to screw you over.

See the chart:http://www.geocities.com/MotorCity/S...53/convert.htm
CC is cubic centimeters, CI is cubic inch, my new toro is 6.75 ft lbs
of crap, it doesnt cut as well as an old 3.5 hp engine, the new
ratings just decieve all. I thought my toro was 6.75 hp, I was ready
to junk it because it bogs so bad.
It is the "old" 4.5 HP, but because of speed limits it is really
only 3 hp - assuming 2400 RPM limit.

On a 24" mower, the blade tip travels 75.36 inches (6.28 ft) per
revolution. At 3600 rpm that is 22,608 ft per minute - well in excess
of the mandated 19,000 limit. The limit is reached at just 3025 RPM.
So IF it is a 24" mower, it is a 3.88 HP mower.


I've never heard of two things mentioned he

#1. a 24" push mower
#2. a 2400 rpm limit

AFAIK, all small engines are governed at 3600 and that's where they operate.

s
Well you are wrong on both counts. I use a 24" rotary "push" mower to
mow my lot all the time, and current lawn mowers are rpm limited to
prevent tip speeds in excess of 19000 ft/minute - and in some cases
14000. It's the LAW in Noth America for all home use lawn mowers.
Apparently SOME commercial units may excede the tip speed depending on
other fastors that I am not aware of.

It IS because of this that lawn mower power ratings were changed. The
engine is rated at a given HP at 3600 RPM - but the equipment does not
allow it to run at that speed so the HP rating is no longer valid.