HP vs Torque

[johnrbd]

A 850 H.P. John Deere diesel vs. a steam tractor rated 18 H.P?
It's all about torque and traction... enjoy


http://www.youtube.com/watch_popup?v=FLQhvruimfs

[Beatfarmer]

That's a really fancy plow.

[Jetta03]

OMG, so much baloney in these threads. All other things being equal, the ability of each engine to do work is identical.

With CVT's each optimized to their respective drivetrains' powerbands (ie the engine runs at its peak power continuously), all other factors being equal, both engines will perform identically up that 12% grade with the same load. The amount of work capable of being done is identical in each case, 450 horsepower. The ONLY difference is the diesel does it at 1431 rpm, the gasser does it at 5491 rpm.

They leave the line identically (because of the CVT's they are both making exactly 450 hp from the get go), they accelerate identically (still 450 hp the whole way, CVT remember?), they arrive at the finish line identically (how many hp was that again?).

All other things being equal, all that matters is horsepower output. Whether it is a 6L diesel spinning at 2000 rpm, or a 1cc model airplane engine spinning at a bazillion rpm makes no difference provided they produce the same horsepower.

[OhhWell]

06Fargo wrote:

OhhWell wrote:

06Fargo wrote:

RCMAN46 wrote:
Better yet tie a 15,000 lb trailer behind both and head them up a 12% grade and see what would happen.

Horsepower is king and will always win as long as traction is not lost.

So a 450 hp gas pickup truck will haul 15,000lbs to the top of the grade same no sweat as a 450hp ISX15 truck engine at 1650lb-ft?

No, but given a long enough hill and similar drivetrains with CVT, they would both eventually hit the same top speed. The Gasser would just take a bit longer to get to it.

I don't know about the sweat part.....

Math is not my greatest skill so bear with me:

So if the grade is long enough, and all other factors and weights and CVT's are identical (either engine can run where it makes it's 450hp) a 450hp / 430lbs-ft engine hauls up a 12% grade at the same speed as a 450hp / 1650lb-ft engine?

:h

Yes, eventually. The diesel would get to the top first though due to a better acceleration.

[noteven]

OhhWell wrote:

06Fargo wrote:

RCMAN46 wrote:
Better yet tie a 15,000 lb trailer behind both and head them up a 12% grade and see what would happen.

Horsepower is king and will always win as long as traction is not lost.

So a 450 hp gas pickup truck will haul 15,000lbs to the top of the grade same no sweat as a 450hp ISX15 truck engine at 1650lb-ft?

No, but given a long enough hill and similar drivetrains with CVT, they would both eventually hit the same top speed. The Gasser would just take a bit longer to get to it.

I don't know about the sweat part.....

Math is not my greatest skill so bear with me:

So if the grade is long enough, and all other factors and weights and CVT's are identical (either engine can run where it makes it's 450hp) a 450hp / 430lbs-ft engine hauls up a 12% grade at the same speed as a 450hp / 1650lb-ft engine?

:h

[Dave_H_M]

This post has been a hoot from the get go.

I am now totally convinced after being enlightened that I am going to sell my worthless tow vehicle and get a steam engine to pull my camper. :S :B

[OhhWell]

06Fargo wrote:

RCMAN46 wrote:
Better yet tie a 15,000 lb trailer behind both and head them up a 12% grade and see what would happen.

Horsepower is king and will always win as long as traction is not lost.

So a 450 hp gas pickup truck will haul 15,000lbs to the top of the grade same no sweat as a 450hp ISX15 truck engine at 1650lb-ft?

No, but given a long enough hill and similar drivetrains with CVT, they would both eventually hit the same top speed. The Gasser would just take a bit longer to get to it.

I don't know about the sweat part.....

How about two 20,000lbs motorhomes are going up an incline, one with a 350 HP V10, the other with a 350hp Cummins but the gasser has a 30 speed transmission with an insane 8.53:1 rear gearing. As they are running up the hill, the Gasser driver is freaking out because his engine is roaring and the darn thing is switching gears like crazy while the diesel driver is laughing and tells him that what he gets for driving a gasser... through the window because they are neck and neck. Then of course, the gasser has to pull into a transmission shop as his has self destructed.

Torque at the wheels can be multiplied through gearing, HP cannot.

[noteven]

RCMAN46 wrote:
Better yet tie a 15,000 lb trailer behind both and head them up a 12% grade and see what would happen.

Horsepower is king and will always win as long as traction is not lost.

So a 450 hp gas pickup truck will haul 15,000lbs to the top of the grade same no sweat as a 450hp ISX15 truck engine at 1650lb-ft?

[noteven]

danojeno wrote:

"Yep pretty much sums it up, this is why gassers rev on hills and diesels don't."

I thought it was because diesels made their peak HP at lower RPMs.

It's all explained right here.

[mosseater]

christopherglenn wrote:
And I was under the impression HP was torque @ rpm.

We have a winner! Most don't understand they are directly related.

[danojeno]

"Yep pretty much sums it up, this is why gassers rev on hills and diesels don't."

I thought it was because diesels made their peak HP at lower RPMs.

[Ole_Man_Dan]

campigloo wrote:

Rockrash wrote:
HP= how fast you hit a brick wall.

Torque=. How far you push the brick wall.

Love it!!

Well said.
Towing needs a little torque at low speed.
Jack rabbit starts while towing is suicidal. Ease off...

My PSD has 400+ HP and 750 ft/lbs of torque,
it's a beast in the mountains. Turns mountains into mole hills.
HP alone would probably require me to run higher RPMs.

[dodge_guy]

OhhWell wrote:

Passin Thru wrote:
My GE 6000 HP locomotive with 200,000 ftlb of tractive force will outpull your little JD tractor. It only weighs 432000 lb.

You own a train?

LOL, good one!

[john_bet]

I would be willing to bet the aircraft tow tractor I used when in the USAF weighing 80k and with 450hp would out pull that JD. Just saying.

[OhhWell]

Passin Thru wrote:
My GE 6000 HP locomotive with 200,000 ftlb of tractive force will outpull your little JD tractor. It only weighs 432000 lb.

You own a train?