Disappointed

[JpalmerCass]

Originally Posted by twinboat

In engines, there is no replacement for displacement.

Many who towed with the Ford 3.5 Ecoboost will argue forced induction is a replacement for displacement.

[JpalmerCass]

Originally Posted by Diesel-Lover

Wait wait don't tell me a toy hauler weighing in at 2k? Sounds like the rigged scale I use to show the old woman I am still at the correct weight see.


Torque gets the work done, hp is kewl but actually you need both. Diesels have lots of torque same with electric motors therefore they can move mountains with little help form their friends the hps.

It's the horsepower doing the work; big torque at low rpm means lots of low rpm horsepower. Torque and horsepower are tied in a relationship of torque and rpms. Engines capable of high rpms need less torque for a given horsepower because they rev higher.

[swavescatter]

I took one trip towing a small lightweight camper with my Jeep Rubicon. I had to horsebeat the crap out of it just to maintain 65mph (10 under the limit.)

I traded it in for a Powerstroke and now tow a massive trailer up steep grades without even a downshift at 75mph all day long. Fuel mileage still sucks, but at least I don't feel like I'm going to grenade the motor on a 200 mile trip...

[IBTripping]

Sorry your unibody Xterra isn't sufficient to tow your travel trailer. However, on the plus side, there are a lot of used full size SUVs (built on truck frames) and four door pickups for sale that will easily tow your trailer without trashing the drive train. And, you can cruise at highways speeds all day long. For instance, I've got a low mileage 2004 Dodge Durango that easily tows my 5,000 lb. travel trailer. Good luck.

[Glensouth]

Years ago, before I went to a motorhome, I was trying to pull a 22 Ft travel trailer with a van that had a 352 CUID V8. I found that wouldn’t work if wanted to get anywhere very fast and forget about the mountains. My first rv was a class C with a v10. It did fair on hills and flat ground. It would look at a hill and downshift. Forget about mountains of any size, 4500 rpm at 25 mph on the steeper mountains. As I found out, you need a modern large displacement diesel to pull the larger motorhomes.

[Diesel-Lover]

Before we get too high and mighty and get bucked by Horses here it is from some one else:

As Ricky used to say it esplains every thing (in scientific terms and then in english too).



An engineering firm consultant:





Sanjit Narwekar, Managing Director at Flowian Solutions Pvt. Ltd. (2014-present)
Answered Jun 28, 2018 · Author has 75 answers and 44.4k answer views






Torque is a function of the Pressure(P




) generated due to the combustion of fuel in the cylinder, the Square of the Bore Diameter (B) and the Stroke Length(L).
So, to increase Torque:

1. Increase the Pressure by increasing the compression ratio, changing the fuel or supercharging or turbocharging
2. Increase the Bore Diameter. This is a good one as the Torque increases by the SQUARE of the Bore Diameter. This is behind the trend of Square or Over Square Engines :-). It does not take much to do in manufacturing - just drill a bigger hole!. No extra parts to design, make, lube, cool etc.
3. Increase the stroke length. Not good as this will require a new crankshaft and cylinder head and will also limit the peak RPM and thus the Peak Power. Power is Torque x RPM (see Sanjit Narwekar's answer to How is power related to RPM?)

The explanation / derivation of the formula is below:
This Pressure(P
) acts on the Piston with Area(A).
The Area(A
) of a Piston is a function of its Bore(B) i.e.
A=(PI.B2)/4
or
A=B2.K
(Replacing all the constants by K).
The Pressure(P
) x Area(A) will give us the Force(f). But we want the Torque(T).
The Torque(T
) is nothing but the Force(f) multiplied by the Radius(R) of the crankshaft and the Radius(R) is half of the Length of Stroke(L).
So, Torque is given by T=P.B2.L.K
i.e. Torque=Pressure.Bore2.Stroke.






a Ford aficionado in his own woids.





Illie Csorba, former Field Manager at Ford Motor Company (1986-1995)
Updated Aug 13 · Author has 1.9k answers and 2.7m answer views






For normal driving useage, torque ALWAYS beats horsepower!
Horsepower is the measure of the amount of work an “engine” can perform. It is expressed as a lifting capacity. A 10 hp B&S engine can lift the equivalent weight that 10 “standard” horses can lift (in simple terms).
Torque is the twisting motion that can be applied to an axle. 100 foot pounds of torque apllied to a vehicle axle will determine the rate the vehicle will accelerate.
100 horsepower has the ability to, perhaps , overcome the mechanical and aerodynamic drag of a given vehicle to sustain a speed of 100 miles per hour.
100 foot pounds of torque has the accelerative force to reach 100 miles per hour in 20 seconds for said given vehicle. If the engine horsepower where increased to 125, the vehicle will reach 110 miles per hour, but will take 25 seconds.
However, if torque were increased to 125 foot pounds with horsepower remaining at 100, the vehicle will take 17 seconds to reach 100 miles per hour.
Most people care little about top speed. The speed limits are generally in the 75 mph 125 kph range. Most modern vehicles reach a top speed of 100 mph with 125 bhp. The performance that is important to most people is the zero to 60 mph acceleration time. Most cars with 150 foot pounds of torque will reach 60 mph in 10 seconds. If Honda adds 15 more foot pounds of torque, giving up 15 bhp, the net effect is a loss of perhaps 5 mph in top speed (95) with a decrease of zero to 60 time of 1 second. The car is now faster accelerating but has a lower top speed.
In the end, even 95 mph will get one a speeding ticket. Beating the driver next to you at the light by a second will get one a 4 car length advantage to the next light and no ticket!
I think most people could care less about horsepower. Torque is what people feel as performance!

[Edd505]

Originally Posted by swavescatter

I took one trip towing a small lightweight camper with my Jeep Rubicon. I had to horsebeat the crap out of it just to maintain 65mph (10 under the limit.)

I traded it in for a Powerstroke and now tow a massive trailer up steep grades without even a downshift at 75mph all day long. Fuel mileage still sucks, but at least I don't feel like I'm going to grenade the motor on a 200 mile trip...

GMC 5.3 V8 pulling 5K 5W once. I also went PS and now pull 14K without a problem. Exhaust brake on the newer ones and you need lots less brakes to stop. yep fuel mileage sucks but if I had to worry about mileage I would sell the 5W.

[jimc99999]

Originally Posted by Diesel-Lover

Before we get too high and mighty and get bucked by Horses here it is from some one else:

[snip]

Horsepower is the measure of the amount of work an “engine” can perform. It is expressed as a lifting capacity.

Torque is the twisting motion that can be applied to an axle. 100 foot pounds of torque apllied to a vehicle axle will determine the rate the vehicle will accelerate.

Horsepower is what gets the work done.

In your own example, if you apply 100 ft/lbs of torque to the axle at 1 rpm, that is very little horsepower (0.02) and won't accelerate you very quickly. 100 ft/lbs of torque at 5000 rpm is a lot more horsepower (95) and will do a lot more work. I.e. you will accelerate a lot faster with 100 ft/lbs of torque at 5000 rpm than you will with 100 ft/lbs of torque at 1 rpm.

[Diesel-Lover]

Originally Posted by jimc99999

Horsepower is what gets the work done.

In your own example, if you apply 100 ft/lbs of torque to the axle at 1 rpm, that is very little horsepower (0.02) and won't accelerate you very quickly. 100 ft/lbs of torque at 5000 rpm is a lot more horsepower (95) and will do a lot more work. I.e. you will accelerate a lot faster with 100 ft/lbs of torque at 5000 rpm than you will with 100 ft/lbs of torque at 1 rpm.

If you read just a tad further you get this:
100 foot pounds of torque has the accelerative force to reach 100 miles per hour in 20 seconds for said given vehicle. If the engine horsepower where increased to 125, the vehicle will reach 110 miles per hour, but will take 25 seconds.
However, if torque were increased to 125 foot pounds with horsepower remaining at 100, the vehicle will take 17 seconds to reach 100 miles per hour.

[jimc99999]

Originally Posted by Diesel-Lover

If you read just a tad further you get this:
100 foot pounds of torque has the accelerative force to reach 100 miles per hour in 20 seconds for said given vehicle. If the engine horsepower where increased to 125, the vehicle will reach 110 miles per hour, but will take 25 seconds.
However, if torque were increased to 125 foot pounds with horsepower remaining at 100, the vehicle will take 17 seconds to reach 100 miles per hour.

You're using made up torque, horsepower, acceleration and speed numbers with no reference to gearing, power curves, etc. Of course the numbers can be whatever you want them to be.


You take a 100 lb vehicle with 100 ft/lb of torque from 1-1000 rpm (nice flat torque curve for you). I'll take a 100 lb vehicle with 50 ft/lbs from 4000-5000 rpm (nice flat torque curve for me too). Who wins, your vehicle with 100 ft/lbs of torque or my vehicle with 50 ft/lbs of torque? Yours with 0-19hp, or mine with 38-47 hp? (Gearing is appropriate for the motor.)


Torque numbers by themselves are meaningless. An HP number by itself is less meaningless, but doesn't tell the whole story either. However, a vehicle with a motor producing 300 hp will accelerate faster than that same vehicle with a motor producing 20 hp, end of story. A vehicle with 300 ft/lbs of torque might or might not accelerate faster than the same vehicle with a motor producing 20 ft/lbs of torque, because the 300 ft/lbs of torque motor would produce 28 hp at 500 rpm, while the 20 ft/lbs of torque motor would produce 38 hp at 10000 rpm.

[jimc99999]

Originally Posted by Diesel-Lover

For normal driving useage, torque ALWAYS beats horsepower!

I even found a realistic example for you!

Honda Civic 2.2 i-CTDi (2006-2011)
2.2L turbo-diesel
140 hp @ 4000 rpm
251 lb⋅ft torque @ 2000 rpm
~ 3000 lbs

Honda Civic Si (2006-2011)
2.0L gas normally aspirated
197 hp @ 7800 RPM
139 lb⋅ft torque @ 6200 RPM
~ 3000 lbs

Since torque is always better, the 250 ft/lb turbo-diesel should be much faster than the 139 ft/lb Si, right?

I-CTDi - 250 ft/lb
0-100 kph - 9.2s
0-160 kph - 25.8

Si - 139 ft/lb
0-100 kph - 6.8s
0-160 kph - 16.6s

Shocking! The Civic with nearly double the torque is significantly slower! I wonder how that could be? Surely not because the Si has 40% more horsepower?

[Diesel-Lover]

Originally Posted by jimc99999

I even found a realistic example for you!

Honda Civic 2.2 i-CTDi (2006-2011)
2.2L turbo-diesel
140 hp @ 4000 rpm
251 lb⋅ft torque @ 2000 rpm
~ 3000 lbs

Honda Civic Si (2006-2011)
2.0L gas normally aspirated
197 hp @ 7800 RPM
139 lb⋅ft torque @ 6200 RPM
~ 3000 lbs

Since torque is always better, the 250 ft/lb turbo-diesel should be much faster than the 139 ft/lb Si, right?

I-CTDi - 250 ft/lb
0-100 kph - 9.2s
0-160 kph - 25.8

Si - 139 ft/lb
0-100 kph - 6.8s
0-160 kph - 16.6s

Shocking! The Civic with nearly double the torque is significantly slower! I wonder how that could be? Surely not because the Si has 40% more horsepower?

Leaving the dramatics aside, I stated torque is what gets the work done, I did not state HP is not necessary, that was an assumed thing by you. As an extreme example a low hp electric motorcycle out accelerates a gasser by huge proportions due to instant torque, mate that to a transmission for exotic performance. Finally if you hang a trailer on both those skates the diesel would run over the SI going up the passes as the SI would slow down bigly. But now we are devolving into the gas vs diesel muck.



BTW yes there are gassers with good low end torque as well not just diesels the thing is they not building larger ones as diesel has that cornered. BTW if you augment with electric then I would bet that a gasser with electric assist could be equal or better than diesel alone, but then if you augment diesel with electric wow but hey with lower mpg requirements I don't see diesel electric drive trains arriving like they are in europe. The Train system realized that diesel torque is good but with electric the torque is fantastic but its all good you win I loose carry on.

[PDL]

WOW... in the time I have been following the IRV2 blogs, I have never seen so many say so little about someone’s question. This one was painful. Good luck with the XTerra.

[mobilemike]

Originally Posted by PDL

WOW... in the time I have been following the IRV2 blogs, I have never seen so many say so little about someone’s question. This one was painful. Good luck with the XTerra.

Hey! I made a fool of myself and then corrected it and posted directly about the Xterra!
So I am good right?