v10 torque vrs diesel

[tres_perros]

Hello folks

I have been looking for a used class A leaning towards a diesel as I plan on towing a Jeep and travel west coast, rockies

Evidentially I am told that the newer V10 fords have very similar torque range ( a model change with an extra valve)

So Id love to hear some opinions regarding this, including if maintenance/warranty contracts are any cheaper...

Thanks ahead of time! This is a great forum and has been very helpful

Keith

[topflite51]

It seems that the consensus opinion is and will always be -

Which ever I own is the best.😛

So be happy with whatever you own as you bought the best in your opinion that there is.:b

[uncleluap]

argue till the cows come home but a known fact is this.
A 400Hp 500Lb torque gas engine will not propel a 34-38K lb MH up 7% grade at the same speed and ease as a ISL cummns 400HP 1250 lb torque engine
nor will it be as fuel efficient nor will it run as cool nor will it even last 1/10 what a cummins diesel will and thats why u do not see this happening in this day and age.

[Cloud_Dancer]

427435 wrote:

jmtandem wrote:

I am a retired Engineer also and designed engines. You can not argue with the equations above. they work for both gas and diesel,in fact any engine.
Let's keep it simple!! Go to any NASCAR race or drag strip. See that they are talking about weight/HP not torque to make there machines do something faster.
It also works for Motoehomes!!!

The purpose of a race car is to go fast. Horsepower is more important than torque as the car is relatively light and needs to possess violent acceleration and high top speeds. The discussion of this thread is to get a heavy motorhome up a mountain; horsepower is less important than torque. It is not the same desired results as what is needed in a race car. 40,000 pounds of MH towing a 3800 pound car behind up six percent grades that are miles and miles long. It is not the same thing. And what does the Holiday Inn reference mean?

In either case, speed on a race track or speed of a heavy MH up an incline----------the more hp, the faster you go. What a high torque rated engine may give you is less need to shift gears frequently.

Again, no one has explained how a high reving gas turbine (with torque levels under 300 ft-lbs) can move heavy tanks up steep inclines if it is only engine torque that does it.

It's THRUST that propels that tank. And, if you give me the total gear ratio and the rolling radius of the track drive, I'll calculate the amount of thrust.

[427435]

jmtandem wrote:

I am a retired Engineer also and designed engines. You can not argue with the equations above. they work for both gas and diesel,in fact any engine.
Let's keep it simple!! Go to any NASCAR race or drag strip. See that they are talking about weight/HP not torque to make there machines do something faster.
It also works for Motoehomes!!!

The purpose of a race car is to go fast. Horsepower is more important than torque as the car is relatively light and needs to possess violent acceleration and high top speeds. The discussion of this thread is to get a heavy motorhome up a mountain; horsepower is less important than torque. It is not the same desired results as what is needed in a race car. 40,000 pounds of MH towing a 3800 pound car behind up six percent grades that are miles and miles long. It is not the same thing. And what does the Holiday Inn reference mean?

In either case, speed on a race track or speed of a heavy MH up an incline----------the more hp, the faster you go. What a high torque rated engine may give you is less need to shift gears frequently.

Again, no one has explained how a high reving gas turbine (with torque levels under 300 ft-lbs) can move heavy tanks up steep inclines if it is only engine torque that does it.

[daveshan]

I have one question for the HP is all that matters folks.

In the situation I posted back a while where you have a very slow turn right before a steep grade isn't it the torque that accelerates you up that grade? HP=HP is all fine and dandy when you're pulling grades on I-70 but I do mostly 2 lane (with the occasional passing area) mountain roads. Never had a gasser pass or tailgate me yet and I've passed more than a few.

[jmtandem]

I am a retired Engineer also and designed engines. You can not argue with the equations above. they work for both gas and diesel,in fact any engine.
Let's keep it simple!! Go to any NASCAR race or drag strip. See that they are talking about weight/HP not torque to make there machines do something faster.
It also works for Motoehomes!!!

The purpose of a race car is to go fast. Horsepower is more important than torque as the car is relatively light and needs to possess violent acceleration and high top speeds. The discussion of this thread is to get a heavy motorhome up a mountain; horsepower is less important than torque. It is not the same desired results as what is needed in a race car. 40,000 pounds of MH towing a 3800 pound car behind up six percent grades that are miles and miles long. It is not the same thing. And what does the Holiday Inn reference mean?

[Cloud_Dancer]

the silverback wrote:
I am a retired Engineer also and designed engines. You can not argue with the equations above. they work for both gas and diesel,in fact any engine.
Let's keep it simple!! Go to any NASCAR race or drag strip. See that they are talking about weight/HP not torque to make there machines do something faster.
It also works for Motoehomes!!!

IMO nobody here is disputing the horsepower equation, nor the history of its origin.
We recognize that all the manufacturers of both gasoline and diesel engines which are used in motorhomes follow standard procedure with regard to publishing torque and horsepower graphs for their engines.

[Javi1]

the silverback wrote:
I am a retired Engineer also and designed engines. You can not argue with the equations above. they work for both gas and diesel,in fact any engine.
Let's keep it simple!! Go to any NASCAR race or drag strip. See that they are talking about weight/HP not torque to make there machines do something faster.
It also works for Motoehomes!!!

Except for one little thing…. Them boys are trying to get through 1380 feet or get around a ½ to 1 mile oval as quick as they can and they ain’t trying to keep 30,000 plus pounds moving up hill… Horsepower is not a measure of power, it is a measurement of how fast work can be done.. the work is done by torque..

The term horsepower was coined by James Watt in the 1700’s he was best known for his improved steam engines, and used the term to relate steam engine performance to that of horses. At the time horses were the primary energy for applications ranging from pumping water from mines and turning grinding mill wheels to pulling carts and loads. Although opinions vary on exactly how Watt arrived at the number, it’s generally thought that in 1782, he noted how quickly a brewery horse could turn a mill wheel of a certain radius, estimated the amount of force (torque) the horse needed to exert in order to turn the wheel, did the math, and came up with a value of 32,400 ft-lbf/min, later rounded to 33,000 ft-lbf/min. Comparing the power output of a steam engine to an equivalent number of horses was an easy way for prospective engine purchasers to compare power ratings, so the term stuck.

I ain’t retired yet but I did stay in a Holiday Inn one time….:D

[the_silverback]

I am a retired Engineer also and designed engines. You can not argue with the equations above. they work for both gas and diesel,in fact any engine.
Let's keep it simple!! Go to any NASCAR race or drag strip. See that they are talking about weight/HP not torque to make there machines do something faster.
It also works for Motoehomes!!!

[jmtandem]

Perhaps, you can see why I don't like to be lumped in with typical RV buyers.

[tres_perros]

Thanks for all the replies! This question certainly proked a lot of dialog!

Still leaning on the diesel, simply from the power produced at the lower operating rpm...

Humm got to think of the next question....

tres perros

[Cloud_Dancer]

jmtandem wrote:

Well yeah, but they don't want to discuss the real world of selecting/buying a motorhome. They want to simply quote the horsepower formula, and then repeat it several times for good measure,......as if it's more than we can understand.
What nobody seems to understand is that the manufacturers use a gasoline engine if it's appropriate, and the same for a diesel.

Cloud Dancer,

You are correct as the manufacturer's select the best engine, trans, suspension, rear end ratio, axles and tire sizes for the coaches they sell constrained by performance and cost. And buyers can usually rest in the knowledge that what they are purchasing has been carefully selected to provide very satisfactory performance (except perhaps Chinese tires) at a cost that is not prohibitive.

However, there are a few of us here that like to think through the issues and banter around some and have fun discussing how things work and why. It revolves around theory, premise, conclusions and real world experiences. And that is OK, too. No harm no foul.

It is real easy for anybody that does not want to participate in the discussion to just skip it and go purchase the coach that has the floor plan that best suits them.

FYI it's too big of an expense to just go to a dealer and buy the coach that has the floor plan that best suits me(no such thing). I don't do it that way, and I didn't do it that way. I took two(2) years to do the research on what was available, and why. And, I special ordered my motorhome with the chassis I wanted, and had Newmar custom make the modifications I wanted in the floorplan, and had them install all the equipment of my choice. And, I did all the calculations to determine how much thrust was required to hold a certain speed when climbing a 6% grade, WITHOUT shifting down more than one gear, while pulling a certain load. You see, I started out with a long list of "must have" features(deal breakers). ALSO, part of my research included finding a dealer somewhere in the USA that was willing to handle the special order PLUS give me a 27% discount on the total price, including all options and custom features. Then, I picked it up at the factory so that I could inspect it, and have the factory redo whatever they got wrong. I was there 10 days.
BTW I never met any of the people at the dealership(which is in North Dakota), nor have I ever stepped foot on their property.

Perhaps, you can see why I don't like to be lumped in with typical RV buyers.

[DanTheRVMan]

Javi1 wrote:

DanTheRVMan wrote:

Javi1 wrote:
Torque is a measure of the ability of an engine to do work. It's a component of, but not the same as, the horsepower of the engine, which is the rate at which work can be done. In an automotive engine, power and torque are related by a simple equation that considers torque, engine speed (in revolutions per minute), and a conversion factor of 5252
Torque x RPM / 5252
In this equation, torque is expressed in terms of ft-lbs, the engine speed is given in revolutions per minute, and 5252 is a conversion constant. An engine's horsepower, then, isn't constant, but rather varies with its speed.
Here’s the problem with horsepower... it is the potential or speed at which work can be done while torque is the ability to work....
While it is possible to take two 350 hp engines and make the same speed pulling the same load up an incline the one with the most torque at the lowest rpm is going to get there cheaper and usually faster because the other will require more gear reduction to produce the same forward force... Which will result in higher rpm’s needed, more fuel burned and more heat produced of which requiring more cooling which adds weight which requires more power (torque) or decrease in payload..
An example is my 6.7 liter diesel which produces 400 HP at 2800 rpm but 800 ft-lbs of torque at 1600 rpm... using the above equation one can see that the 6.7 produces 800 x 1600 / 5252 = 243.72 hp at 1600 rpm, far from the potential peak hp of 400 at 2800 rpm... Although in looking at the torque curve of the 6.7 it is apparent that the 800 ft-lbs is nearly constant through the range of 1600 to 2800 giving the 6.7 a very high work range.
The Ford V-10 gas engine produced 457 ft-lbs of torque at 3250 and 362 hp at 4750 using the above equation one can see that the V-10 produced 457 X 3250 / 5252 = 282.79 hp a gain of 39.07 HP but at the cost of more than twice the revolutions... to produce slightly more than ½ the torque of the 6.7 diesel.
While the design of the gas V-10 is aimed at higher RPM the life expectancy of an engine turning at well over twice it’s normal operating range is almost certainly going to be reduced by some factor if one expects it to produce the same work ability through increased rpm.. and gearing..

You are right about the shape of a gas engines torgue curve, but gas engines are lighter not heavier than diesels.

Speed is determined by weight/hp and gas MHs are generally much lighter than diesels MHs so for the same HP a gas MH will be faster in spite of the worse shape of torque or hp curves.

As for the life of the engines you are correct the diesel should last lots longer. But since gas will last over 100k and most people wear out the house first this is not a good reason for many people to blow their budget and buy a diesel so the fourth owner can go a few more miles.

Yes, generally a gas engine is found in a smaller coach, however the original question was (I think) about the same size coach just gas or diesel powered.. in which case unless it was one of the smaller coaches.. the diesel will win, especially if you base winning on longivity X power / fuel expense.

I agree with you concerning longevity IF you consider longevity of the engine. BUT, if you think of longevity of the house then the gas is more than sufficient for many buyers.

As to fuel expense I think that is a very small consideration. I am averaging just over 9 mpg towing on a 6+ month trip and depreciation is the big expense, with CG costs second. The added fuel expense if I owned a gas MH would be rather small.

[catallison777]

another one of these threads.....................

[jmtandem]

Well yeah, but they don't want to discuss the real world of selecting/buying a motorhome. They want to simply quote the horsepower formula, and then repeat it several times for good measure,......as if it's more than we can understand.
What nobody seems to understand is that the manufacturers use a gasoline engine if it's appropriate, and the same for a diesel.