Comparison LS XG 3140 HP specs are wrong

[polemidis]

I am reading from the manual:
Maximum torque: 134Nm @1600rpm
Engine Rated Power: 29.88kW@2600rpm (39.96Hp@2600)

That simply does not make sense. Do they mis-advertise their product?

The formula for power/torque is Hp = Nm x rpm / 9550, so
torque= power * 9550/ rpm => 39.96Hp/2600rpm*9550= 146.77Nm


So either I am wrong in my simple calculation, or they advertise more Horsepower, or they advertise less max torque. Can you help me clear this out plz?

 

[Jstpssng]

Are both referring to engine horsepower, or is the first the rating at the PTO?

 

[polemidis]

Its clearly on the engine specs.

 

[chim]

One HP = 746 W

So in round numbers 40 HP x .746=29.8KW

 

[George2615]

The difference is the RPM's. It makes max torque @ 1600 RPM but max HP @2600 RPM's. It doesn't make max HP and Torque at the same RPM.. At max torque of 1600 RPM it is only making 22.45HP based on the formulas in post 1.

 

[finn1]

Peak torque always occurs at a lower rpm than peak power. That is, as the engine lugs down from rated speed /power under load, the torque increases.

Without this feature, called torque rise, the engine would fall on its face when the load increases under heavy load, such as pulling a ground engaging implement.

15% torque rise used to be considered a desirable torque rise target for farm equipment.

 

[polemidis]

Guys I think I didnt stated very clear the issue.
If what they rated the engine for is true, then the torque at 2600rpm is calculated at 146Nm which is more than the stated as MAX at 1600rpm as 134Nm

146 is more than 134! So either they overrated the HP at 2600rpm or the max torque at 1600rpm is underrated

 

[TMGT]

Do all your conversion first then calculate, less chance for errors. I noticed you mixed units of measure in your equation which gave you an inaccurate solution.

I came up with:
@ 1600RPM 30.1hp and 98.83 ft.lbs

@ 2600 rpm 39.96 hp and 80.7 ft.lbs

Sounds right to me

 

[polemidis]

Do all your conversion first then calculate, less chance for errors.

I came up with:
@ 1600RPM 30.1hp and 98.83 ft.lbs

@ 2600 rpm 39.96 hp and 80.7 ft.lbs

Sounds right to me

wtf, I did the calculations in ft. lbs and it sounds good to me too. where am I screwing up? My calculations on my 1st post in Nm still look fine! argggg.

What I am really trying to find is the size/timings of the cylinders for a backhoe that I am designing. And I want to make a good estimation on the hp availabilty and if it worth to use a pto pump instead of the remotes.

 

[TMGT]

"HP=NM x RPM/9550" is wrong, that should be either "Kw=NM x RPM/9550" or "HP=Ft.Lb x RPM/5252"