B&S 6.25 lb-ft = how many HP?
- Thread starter xr650boy
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Most mower engine these days are 6-6.5 hp.
The el-cheap-o mowers are likely 5 hp.
The el-cheap-o mowers are likely 5 hp.
The formula is correct but that will only give you the hp at that particular rpm, not necessarily the max hp.
I think that's so dumb that there doing that now, what the
---- was wrong with the HP rating on these motors???
gezzzz they have a good system and they go and change it all
the time..
---- was wrong with the HP rating on these motors???
gezzzz they have a good system and they go and change it all
the time..
Quote:
I think that's so dumb that there doing that now, what the
---- was wrong with the HP rating on these motors???
gezzzz they have a good system and they go and change it all
the time..
You are absolutely correct. There was nothing wrong with the system of rating engine power by its horsepower. Trouble was, they always rated horsepower at about 3600 rpm, and thereby got a number that was higher than could be legally used due to blade tip speed safety regulations limiting rpm to about 3100.
Some people noticed this, and filed lawsuits charging improper advertising of engine power. To avoid having to advertise a much lower horsepower figure, they went to using torque values, which are comparatively steady on most engines between 2000 and 3500 rpm.
at 3100 r's it would be a 3.68hp motor. basically an old 3 and a half.
the new system of displaying torque is based on the fact that at these lower rpm's the engines have a bigger torque number then horsepower, so naturally jonh q consumer likes big numbers. they want to show the bigger of the 2.
thats ALL it is, marketing. what sounds better, a 6.25ftlb motor, or a 3.5hp motor?
this is just another marketing item, like professional grade, hybrid, etc.
the new system of displaying torque is based on the fact that at these lower rpm's the engines have a bigger torque number then horsepower, so naturally jonh q consumer likes big numbers. they want to show the bigger of the 2.
thats ALL it is, marketing. what sounds better, a 6.25ftlb motor, or a 3.5hp motor?
this is just another marketing item, like professional grade, hybrid, etc.
If that formula is correct, they have been stretching the HP ratings for years. My old mower was a 3.75 HP B&S. My new one is an OHV 6.75 ft-lbs. According to the formula, it would only be around 4 HP at 3100 RPM, or 4.6 at 3600 RPM. I can tell you that it "feels" nearly twice the power as my old.
yes, they have been stretching every number they can sence stream engines were around.
you think thats bad, try those 3/4 "peak" hp garage door openers, 5 "peak" hp compressor motors, etc.
seems like honesty has gone the way of the carburettor.
you think thats bad, try those 3/4 "peak" hp garage door openers, 5 "peak" hp compressor motors, etc.
seems like honesty has gone the way of the carburettor.
From the Briggs website-
The gross power rating for individual gas engine models is labeled in accordance with SAE (Society of Automotive Engineers) code J1940 (Small Engine Power & Torque Rating Procedure), and rating performance has been obtained and corrected in accordance with SAE J1995 (Revision 2002-05). Torque values are derived at 3060 RPM; horsepower values are derived at 3600 RPM. Actual gross engine power will be lower and is affected by, among other things, ambient operating conditions and engine-to-engine variability. Given both the wide array of products on which engines are placed and the variety of environmental issues applicable to operating the equipment, the gas engine will not develop the rated gross power when used in a given piece of power equipment (actual on-site or net horsepower). This difference is due to a variety of factors including, but not limited to, accessories (air cleaner, exhaust, charging, cooling, carburetor, fuel pump, etc.), application limitations, ambient operating conditions (temperature, humidity, altitude), and engine-to-engine variability. Due to manufacturing and capacity limitations, Briggs & Stratton may substitute an engine of higher rated power for this Series engine)
The gross power rating for individual gas engine models is labeled in accordance with SAE (Society of Automotive Engineers) code J1940 (Small Engine Power & Torque Rating Procedure), and rating performance has been obtained and corrected in accordance with SAE J1995 (Revision 2002-05). Torque values are derived at 3060 RPM; horsepower values are derived at 3600 RPM. Actual gross engine power will be lower and is affected by, among other things, ambient operating conditions and engine-to-engine variability. Given both the wide array of products on which engines are placed and the variety of environmental issues applicable to operating the equipment, the gas engine will not develop the rated gross power when used in a given piece of power equipment (actual on-site or net horsepower). This difference is due to a variety of factors including, but not limited to, accessories (air cleaner, exhaust, charging, cooling, carburetor, fuel pump, etc.), application limitations, ambient operating conditions (temperature, humidity, altitude), and engine-to-engine variability. Due to manufacturing and capacity limitations, Briggs & Stratton may substitute an engine of higher rated power for this Series engine)
Quote:
Quote:
I think that's so dumb that there doing that now, what the
---- was wrong with the HP rating on these motors???
gezzzz they have a good system and they go and change it all
the time..
Some people noticed this, and filed lawsuits charging improper advertising of engine power.
Gezzzz i tell ya, people now day's give me a break, who give a ----!!! if the number's are a litte off
I like it better when they just tell you the displacement. There have been a lot of engines advertised with 5.0, 5.5, 6.0 hp ratings on them but they are all the same 190cc engine with a different carburetor or intake manifold.
LOL! That reminds me of that stoooped Honda class-action lawsuit RE: speedometer a little bit "off".
I think kkreit01 and Master ACiD have it right. Lies. These numbers have been gradually growing over the years with few if any changes to the engines. Similar to the imported air compressor horsepower wars.
I guess we're finally seeing the correction. About time.
I guess we're finally seeing the correction. About time.
It also might be because imported engines(ie: Honda and Kawazaki) generally have higher horsepower than Briggs or others have.
Torque sort of evens the field.
Torque sort of evens the field.
Actually, these new ratings make more sense when APPLIED TO WALK BEHIND 21" LAWNMOWERS, since they are taken at similar engine speeds as used on these applications.
A HP rating taken at 3600 RPM is only semi relevant when the engine is used at about 3100 RPM.
It still doesn't show the whole picture however. Torque curves can vary considerably between different engines. OHV OPE engines TEND to have flatter torque curves than flat heads for example. Having the torque rating at 3060 is OK. Having it at a few other RPM points would be better.
What happens when the engine bogs down to 2400 RPM? That info would also be handy, else the engine manfs. could "optimize" the engine for that one speed only to "enhance" their numbers and care less about other speeds that may still matter for that specific application.
Give me torque CHARTS!
A HP rating taken at 3600 RPM is only semi relevant when the engine is used at about 3100 RPM.
It still doesn't show the whole picture however. Torque curves can vary considerably between different engines. OHV OPE engines TEND to have flatter torque curves than flat heads for example. Having the torque rating at 3060 is OK. Having it at a few other RPM points would be better.
What happens when the engine bogs down to 2400 RPM? That info would also be handy, else the engine manfs. could "optimize" the engine for that one speed only to "enhance" their numbers and care less about other speeds that may still matter for that specific application.
Give me torque CHARTS!
You guys are really overthinking this.
Yes, and your point is
. I mean, it's what we do here. If it's not taken to the nth degree, it's not worth talking about.
some manf to give you torque charts.
heres the hp and torque chart for the gcv 160 push mower engine.
http://www.honda-engines.com/curves/curve_GCV160.gif
look at that torquey little 160cc motor!
heres the hp and torque chart for the gcv 160 push mower engine.
http://www.honda-engines.com/curves/curve_GCV160.gif
look at that torquey little 160cc motor!
benjamming is right. Where's the fun if you can't overthink these things?
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