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RATINGS: HP vs TORQUE
#1
twall
twall
So, you look at an ad for a mower.
Looks okay for the weedeater one. Its a tiny little RER. 9 should be enuff.
HP? The Hp rating is 6.5 horse. Now that's a number I'm familiar with, and that's pathetic. I've used 8hp RER's, and that was barely sufficient, if you have a rainy month.
Why do they do that? It's said, 'torque is more what you'll need, so its a better gauge'. Really? I know what a 6.5 horse is like. But, I really have nothing to gauge torque by, because for the last 50 years or so, they've used Hp ratings!! Did they do anything to 'up' the torque? No. Then why use it? To confuse you. That way, they can use a cheaper engine with a different rating, and you think it's either okay, or just a tad anemic for a 9hp. But it isn't 8.75 HORSE, it's TORQUE. A 9horse would probably net you 14 ft/lbs. Then you'd think it's a 14hp. See?
'Seat of the pants' is a bad dyno.
What do you think?
- 190cc
- 8.75 ft/lbs torque
- Hp - none listed
Looks okay for the weedeater one. Its a tiny little RER. 9 should be enuff.
HP? The Hp rating is 6.5 horse. Now that's a number I'm familiar with, and that's pathetic. I've used 8hp RER's, and that was barely sufficient, if you have a rainy month.
Why do they do that? It's said, 'torque is more what you'll need, so its a better gauge'. Really? I know what a 6.5 horse is like. But, I really have nothing to gauge torque by, because for the last 50 years or so, they've used Hp ratings!! Did they do anything to 'up' the torque? No. Then why use it? To confuse you. That way, they can use a cheaper engine with a different rating, and you think it's either okay, or just a tad anemic for a 9hp. But it isn't 8.75 HORSE, it's TORQUE. A 9horse would probably net you 14 ft/lbs. Then you'd think it's a 14hp. See?
'Seat of the pants' is a bad dyno.
What do you think?
#2
JDgreen
I think you have a justifiable rant here, I was used to hp ratings too. Not too sure of the situation and you may not know about it yourself but recently there was one of those class action lawsuits going around to push mower owners. Supposed to have been based on the fact that the makers of certain brands of mowers had overstated the developed hp of their engines and if you owned one you were entitled to a cash settlement. I had three mowers that qualified under the rules but didn't do anything to participate because the lawyers were the ones who would end up with $$ not me. Anyhow I think that is why they now use torque ratings because they have to scale the hp claims way down.
I could be wrong.,,but do a Google search for "Lawn mower class action".
JDgreen
So, you look at an ad for a mower.
- 190cc
- 8.75 ft/lbs torque
- Hp - none listed
Looks okay for the weedeater one. Its a tiny little RER. 9 should be enuff.
HP? The Hp rating is 6.5 horse. Now that's a number I'm familiar with, and that's pathetic. I've used 8hp RER's, and that was barely sufficient, if you have a rainy month.
Why do they do that? It's said, 'torque is more what you'll need, so its a better gauge'. Really? I know what a 6.5 horse is like. But, I really have nothing to gauge torque by, because for the last 50 years or so, they've used Hp ratings!! Did they do anything to 'up' the torque? No. Then why use it? To confuse you. That way, they can use a cheaper engine with a different rating, and you think it's either okay, or just a tad anemic for a 9hp. But it isn't 8.75 HORSE, it's TORQUE. A 9horse would probably net you 14 ft/lbs. Then you'd think it's a 14hp. See?
'Seat of the pants' is a bad dyno.
What do you think?
I think you have a justifiable rant here, I was used to hp ratings too. Not too sure of the situation and you may not know about it yourself but recently there was one of those class action lawsuits going around to push mower owners. Supposed to have been based on the fact that the makers of certain brands of mowers had overstated the developed hp of their engines and if you owned one you were entitled to a cash settlement. I had three mowers that qualified under the rules but didn't do anything to participate because the lawyers were the ones who would end up with $$ not me. Anyhow I think that is why they now use torque ratings because they have to scale the hp claims way down.
I could be wrong.,,but do a Google search for "Lawn mower class action".
#3
S
SeniorCitizen
S
SeniorCitizen
QUOTE: What do you think?
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
I think you are worrying about things that don't need to be worried about.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
I think you are worrying about things that don't need to be worried about.
#4
I
indypower
I
indypower
Briggs & Stratton started the "torque" ratings. Their engines supposedly have more torque than other engines. I agree it is confusing when everyone can relate to horsepower, which has been used since the first internal combustion engine was made. But a lawsuit by someone who claimed the horsepower of his engine was not what was stated. So now engine manufacturers state the CC's and Briggs also states the torque. The EPA should dyno test he engines for horse power and those ratings should be used. I do find it strange that only the smaller engines (less than 15 hp), push mower & snow blower use the CC's while lawn tractor engines still list the Horse power.
#5
JDgreen
GOOD POST!! :thumbsup:
JDgreen
Briggs & Stratton started the "torque" ratings. Their engines supposedly have more torque than other engines. I agree it is confusing when everyone can relate to horsepower, which has been used since the first internal combustion engine was made. But a lawsuit by someone who claimed the horsepower of his engine was not what was stated. So now engine manufacturers state the CC's and Briggs also states the torque. The EPA should dyno test he engines for horse power and those ratings should be used. I do find it strange that only the smaller engines (less than 15 hp), push mower & snow blower use the CC's while lawn tractor engines still list the Horse power.
GOOD POST!! :thumbsup:
#6
twall
HUH?:confused2:
They DO, to me, because if I'm buying a mower, why bother putting ANY number on there, if they're gonna use a new standard every few years? OR (even better) if I'm buying a replacement engine. If I know what my 12 horse is like, and it worked well - why do I have to have a scientific calculator and formulas from the machinist's handbook to figure out what I need to replace it with? If I get the really WRONG engine, it'll either not do the job, or it'll tear my equipment to pieces by over - powering it. What an engine costs + shipping these days, I'd kinda like to be sure, before I whip out my Mastercard and place an order.
Seems quite relevant, but thanks for voting!
twall
QUOTE: What do you think?
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
I think you are worrying about things that don't need to be worried about.
HUH?:confused2:
They DO, to me, because if I'm buying a mower, why bother putting ANY number on there, if they're gonna use a new standard every few years? OR (even better) if I'm buying a replacement engine. If I know what my 12 horse is like, and it worked well - why do I have to have a scientific calculator and formulas from the machinist's handbook to figure out what I need to replace it with? If I get the really WRONG engine, it'll either not do the job, or it'll tear my equipment to pieces by over - powering it. What an engine costs + shipping these days, I'd kinda like to be sure, before I whip out my Mastercard and place an order.
Seems quite relevant, but thanks for voting!
#7
RobertBrown
I think what Sandbur is trying to say is the manufacturer knows what you want and is doing his best to meet your needs. It's not in his best interest to sell you a mower that won't meet your expectations whether it be rated in hp or ft.lbs.
You want a high wheel mulching mower, you buy it and take it home because the last one you had worked great, it was 6.25HP.
If this one doesn't get the job done, what are you going to do? Take it back. They don't want that. So the machine should be adequate or they lose the profit.
RobertBrown
HUH?:confused2:
They DO, to me, because if I'm buying a mower, why bother putting ANY number on there, if they're gonna use a new standard every few years? OR (even better) if I'm buying a replacement engine. If I know what my 12 horse is like, and it worked well - why do I have to have a scientific calculator and formulas from the machinist's handbook to figure out what I need to replace it with? If I get the really WRONG engine, it'll either not do the job, or it'll tear my equipment to pieces by over - powering it. What an engine costs + shipping these days, I'd kinda like to be sure, before I whip out my Mastercard and place an order.
Seems quite relevant, but thanks for voting!
I think what Sandbur is trying to say is the manufacturer knows what you want and is doing his best to meet your needs. It's not in his best interest to sell you a mower that won't meet your expectations whether it be rated in hp or ft.lbs.
You want a high wheel mulching mower, you buy it and take it home because the last one you had worked great, it was 6.25HP.
If this one doesn't get the job done, what are you going to do? Take it back. They don't want that. So the machine should be adequate or they lose the profit.
#8
twall
twall
Although i see what you're saying, i still think half of it is mental. We may have been over buying, and a lesser engine will get the job done, but its still a game. I'm not fond of games.
Good reply, tho. You may sway me yet to the benevolence of the manufacturer yet. :wink:
Although you seemed to skim over my point of replacement engines.
Good reply, tho. You may sway me yet to the benevolence of the manufacturer yet. :wink:
Although you seemed to skim over my point of replacement engines.
#9
S
SeniorCitizen
Since the new adopted ratings, a new replacement will be listed as cc so that shouldn't be a problem.
But just in case you opt for an older replacement engine this link should give you all the information you would ever need.
Convert cc to hp or horsepower to cu.in. cc or cu.cm metric conversions
S
SeniorCitizen
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^Although i see what you're saying, i still think half of it is mental. We may have been over buying, and a lesser engine will get the job done, but its still a game. I'm not fond of games.
Good reply, tho. You may sway me yet to the benevolence of the manufacturer yet. :wink:
Although you seemed to skim over my point of replacement engines.
Since the new adopted ratings, a new replacement will be listed as cc so that shouldn't be a problem.
But just in case you opt for an older replacement engine this link should give you all the information you would ever need.
Convert cc to hp or horsepower to cu.in. cc or cu.cm metric conversions
#10
RobertBrown
Now if your buying an engine for your own design, say for a pump, saw or compressor. You probably already have the skills to size it correctly.
RobertBrown
It's not an issue....How many choices are you going to get for the engine that bolts up and has the correct apurtenances?Although i see what you're saying, i still think half of it is mental. We may have been over buying, and a lesser engine will get the job done, but its still a game. I'm not fond of games.
Good reply, tho. You may sway me yet to the benevolence of the manufacturer yet. :wink:
Although you seemed to skim over my point of replacement engines.
Now if your buying an engine for your own design, say for a pump, saw or compressor. You probably already have the skills to size it correctly.
#11
K
KennyV
K
KennyV
Dee now this is exactly what I have been missing...
Glad to be back.
I am wondering if the torque ratings are peak torque or the actual torque at the proper RPM... most small engines on lawnmowers are set up to run around 3600 RPM... Hmmmmmm... :smile:KennyV
:smile:OH did I mention I have really missed everyone here....:smile:
Glad to be back.
I am wondering if the torque ratings are peak torque or the actual torque at the proper RPM... most small engines on lawnmowers are set up to run around 3600 RPM... Hmmmmmm... :smile:KennyV
:smile:OH did I mention I have really missed everyone here....:smile:
#12
JDgreen
Good question...I have always wished there was a small tachometer, a CHEAP one, that you could buy to measure rpm of a small engine...I have seen some advertised with a digital readout for an ATV but they were very costly.
JDgreen
Dee now this is exactly what I have been missing...
Glad to be back.
I am wondering if the torque ratings are peak torque or the actual torque at the proper RPM... most small engines on lawnmowers are set up to run around 3600 RPM... Hmmmmmm... :smile:KennyV
:smile:OH did I mention I have really missed everyone here....:smile:
Good question...I have always wished there was a small tachometer, a CHEAP one, that you could buy to measure rpm of a small engine...I have seen some advertised with a digital readout for an ATV but they were very costly.
#13
H
handirifle
H
handirifle
Hi all, first post here. I am posting on this one cause I ran into this issue on a couple different fronts, in the last year. The first, was when i bought a tiller, and noticed the rating of 9lbs torque, hmmmmm.
I agree on the issue of what is really doing the work, it is torque, not hp, but it's all a numbers game. Auto makers went for MANY years without publishing HP or torque figures, because of lawsuits. Their needs to be tolerances they are allowed, as I'm sure everyone is aware, no two engines will produce the same HP, even when built identical.
The second was when I bought a used Murray 20HP (B&S) Garden Tractor, with 52" cut, to mow my 3 acres. I ran it a total of 2 hrs, before it floated an exhaust valve seat, shutting the engine down. The interesting part came when contacting B&S about replacement parts/engine, the recommended replacement was a 26hp Vtwin to replace my 20hp flat twin. His reply was even though the hp of newer engine was higher, mine had greater displacement (and I suspect greater torque) and this was what would work.
I agree on the issue of what is really doing the work, it is torque, not hp, but it's all a numbers game. Auto makers went for MANY years without publishing HP or torque figures, because of lawsuits. Their needs to be tolerances they are allowed, as I'm sure everyone is aware, no two engines will produce the same HP, even when built identical.
The second was when I bought a used Murray 20HP (B&S) Garden Tractor, with 52" cut, to mow my 3 acres. I ran it a total of 2 hrs, before it floated an exhaust valve seat, shutting the engine down. The interesting part came when contacting B&S about replacement parts/engine, the recommended replacement was a 26hp Vtwin to replace my 20hp flat twin. His reply was even though the hp of newer engine was higher, mine had greater displacement (and I suspect greater torque) and this was what would work.
#14
rer
rer
Speaking of hp and torque rating I actually did some sizing up today. A big wheel I have has a Briggs and Stratton 6.75lb/ft torque rating, but further examination found it is the exact engine as my older 5.5hp right down to the float bowl. All parts were the exact match Bore and stroke measured exactly the same. Also that same 6.75 is also 9.14 newton meters.:biggrin:
#15
J
jeff
J
jeff
H.P. will have a lot of variables with the same displacement engine due to little things like valve timing and lift, carb jetting compression, etc. Ask anyone who has hotroded a small block chev.
#16
T
txyank1
T
txyank1
OK, new member here. I've read the thread and didn't see exactly what I was looking for. I haven't bought a mower (rotary, push mower) since the rating change to torque. It's time to replace my Craftsman 6.25 HP and I want something with as much and preferably more power. What do I look for?:confused2:
Thanks
Thanks
#17
doug9694
I use 1hp per every 1.5 PT (foot per torque per rpm) It is based on the formula of 1hp = 1 PT at 5,252 RPM. Since most mower and equipment engines are rated near 3600, you need more torque to equal the 5,252 ft lbs. That cc per hp rating does not make since.
OHV engines have more hp than flat heads for the same size cc. Also compression ratios will change the hp rating. Next I expect all the ratings to be switched to metric. KW or MN or ???. Then we will have to learn all over again.
I would like to see them give both. TP and hp in parentheses at least.
doug9694
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Since the new adopted ratings, a new replacement will be listed as cc so that shouldn't be a problem.
But just in case you opt for an older replacement engine this link should give you all the information you would ever need.
Convert cc to hp or horsepower to cu.in. cc or cu.cm metric conversions
I use 1hp per every 1.5 PT (foot per torque per rpm) It is based on the formula of 1hp = 1 PT at 5,252 RPM. Since most mower and equipment engines are rated near 3600, you need more torque to equal the 5,252 ft lbs. That cc per hp rating does not make since.
OHV engines have more hp than flat heads for the same size cc. Also compression ratios will change the hp rating. Next I expect all the ratings to be switched to metric. KW or MN or ???. Then we will have to learn all over again.
I would like to see them give both. TP and hp in parentheses at least.