Horsepower

[auggy53]

I have a lawn tractor that's supposed to be 17 h.p. , an 8n is what , 20-22 h.p. Where is that horsepower measured ?

 

[JMOR]

(quoted from post at 21:33:55 05/05/15) I have a lawn tractor that's supposed to be 17 h.p. , an 8n is what , 20-22 h.p. Where is that horsepower measured ?

P is not HP. Measured in many different ways & many are not even honest. Wasting you time.

 

[auggy53]

thats fine jmor , i have the time to waste . im sure its just an equation until it is actually dyno tested like a race car . im just courious as to why there is only 3 or 4 h.p. difference in a lawn mower and an 8n.

 

[Ken(Ark)]

(quoted from post at 20:33:55 05/05/15) I have a lawn tractor that's supposed to be 17 h.p. , an 8n is what , 20-22 h.p. Where is that horsepower measured ?

I have no actual numbers so I will make up numbers just to explain a little .

Your 17hp lawnmower is probably getting that number @ 3600 rpm which is probably about topped out . It also has a low torque numbers , lets say "50" foot pounds @ 1200 rpm

Your 22hp tractor would probably produce mid 30's hp @ 3600 rpm and lets say has "150" foot pounds of torque @ 1200 rpm .

So the 17hp is an apple and the 22hp is an orange .

 

[JMOR]

(quoted from post at 22:42:43 05/05/15) thats fine jmor , i have the time to waste . im sure its just an equation until it is actually dyno tested like a race car . im just courious as to why there is only 3 or 4 h.p. difference in a lawn mower and an 8n.

K, so they lie on the lawn tractor with a "peak HP" instantaneous number & they use actual drawbar pulling HP on the N at governed speeds.. If you research the dyno HP numbers on the N engine at max rpm ( about 2X governed) you will find about 45 HP.

 

[Ken(Ark)]

OK, so they lie on the lawn tractor with a "peak HP"

Is that a salesmans term for "just before it explodes" :wink:

 

[auggy53]

thanks ken , you made it simple enough . what i heard you say was both machines are designed for a specific purpose . like my circular saw and my geardrive circular saw .

thanks again

 

[Dean]

The late model 8N is rated at 27 HP on the belt at 2100 RPM. It will do this all day, day after day for years.

Your lawn mower is rated at ? HP at 3200 or 3600 RPM at the crankshaft (probably without any parasitic loads). It will do this all day, day after day for a few days.

Dean

 

[ScoutB]

(quoted from post at 22:42:43 05/05/15) thats fine jmor , i have the time to waste . im sure its just an equation until it is actually dyno tested like a race car . im just courious as to why there is only 3 or 4 h.p. difference in a lawn mower and an 8n.

Yup. The equation is HP = T(ft-lb) x RPM/5252. As Ken said, peak HP is at max RPM just before it explodes in today's marketing atmosphere, not at realistic operating conditions.

 

[auggy53]

iheard someone on here
explain it as spontanious dissasembly

i like that fraze better...........

thank again ken

 

[Ken(Ark)]

(quoted from post at 22:19:44 05/05/15) thanks ken , you made it simple enough . what i heard you say was both machines are designed for a specific purpose . like my circular saw and my geardrive circular saw .

thanks again

Horsepower would be the energy to load 10 bags of feed in the back of the truck . Torque would be 1 bag 10 times vs. 10 bags at once , kinda ?

 

[Richard G.]

That 8N is at least 63 years old. How long you think that lawn "tractor" will last?
Richard in NW SC

 

[TheOldHokie]

(quoted from post at 21:33:55 05/05/15) I have a lawn tractor that's supposed to be 17 h.p. , an 8n is what , 20-22 h.p. Where is that horsepower measured ?

For engines it is measured at the flywheel/crankshaft. Keep in mind HP is a function of RPM so you actually need to know HP@RPM to get even a modestly meaningful comparison.

TOH

 

[souNdguy]

Agreed, dishonest is about the best way to call it. measuring engines at higher than normal rpm, perhaps different oil and fuel, and reduced number of engine loads.. ie.. no pumps, etc.

 

[JMOR]

Like the 5 HP shop vac! Would probably need about 50 amperes out of you 15A receptacle to obtain the 5HP. Like I said, they lie a lot.

 

[souNdguy]

I especially love the electrical HP numbers. ( peak hp is a common one )

 

[fubar2]

Compare the weight of the rotating mass of your 8n and your lawnmower. You'll find your answer there.

 

[ScoutB]

(quoted from post at 14:24:50 05/06/15) I especially love the electrical HP numbers. ( peak hp is a common one )

I've got a 220/1/60 compressor that claims to be 7 HP. Impressive, don't you think?

 

[phil_n]

Why not get an old N with a blown motor and put a lawnmower motor in it? Should work.

 

[NoNewParts]

Horsepower makes noise, Torque does work.

(quoted from post at 02:58:56 05/07/15) Why not get an old N with a blown motor and put a lawnmower motor in it? Should work.

I have a Oliver/Cletrac HG crawler with a 2 cylinder vertical shaft Briggs engine.
Good thing it has the 2 transmissions.
Pretty useless, but my grandson likes it (......me too)

 

[souNdguy]

Better than the ones claiming high hp on 120!