โOct-04-2012 05:21 PM
โOct-06-2012 03:10 PM
uncleluap wrote:
we can banter back and forth till the cows come home,use 5252X whatever
Use whatever formula u were taught.I have no knowledge of such stuff
I absolutely know one thing for sure.There is not a V8 or V10 in production today that come,s even close to being able to feasable propel a 40+Ft 4 slide 34K motorhome down the road and up mountain passes and if there was we would be seeing them.thats why we only see engines like the 425 8.9L cummins doing the job and not ford V10.thats my opinion
โOct-06-2012 03:00 PM
โOct-06-2012 02:47 PM
uncleluap wrote:Cloud Dancer wrote:
uncleluap,
Please explain this, because I don't believe it's the reason:
"......The reason you don't see gassers in bigger MH's is that the people with the money for a 40' MH are also willing to pay the money for an air-ride suspension system and to have the engine/transmission in the back (quieter)...."
sorry cant help you as i never posted that dribble? I laughed actually when i saw that as in my opinion thats not the reason.I think u mixed up my stuff with others perhaps/
โOct-06-2012 02:06 PM
Cloud Dancer wrote:
uncleluap,
Please explain this, because I don't believe it's the reason:
"......The reason you don't see gassers in bigger MH's is that the people with the money for a 40' MH are also willing to pay the money for an air-ride suspension system and to have the engine/transmission in the back (quieter)...."
โOct-06-2012 01:42 PM
โOct-06-2012 01:25 PM
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.
Hereโs 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 rpmโs 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 ยฝ 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 itโs 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.
โOct-06-2012 01:14 PM
Jarlaxle wrote:uncleluap wrote:
427435 I absolutely disagree with your statement:
Again, it's not the torque but the hp (and enough gears) that actually move a MH uphill.
The reason you don't see gassers in bigger MH's is that the people with the money for a 40' MH are also willing to pay the money for an air-ride suspension system and to have the engine/transmission in the back (quieter).
first off air ride suspention has nothing to do with what we are discussing and as i alluded to earlier there just is not a gas engine avaialable that has the torque or durabilty to propel 40Ft+ 36k+ motorhomes down the road.
its been tryed before and failed miserable
This post can only be called a LIE.
โOct-06-2012 01:13 PM
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.
Hereโs 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 rpmโs 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 ยฝ 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 itโs 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..
โOct-06-2012 12:52 PM
โOct-06-2012 11:46 AM
โOct-06-2012 10:06 AM
Actually, they will. I have seen it firsthand: we had two 275HP semi tractors at work...one made it at ~2300RPM with a little C7, the other at ~1700RPM with a big C10. Hauling the same weight, they would climb hills at EXACTLY THE SAME SPEED. The smaller engine just had to run higher RPM's...it was no problem, as it was geared accordingly.
โOct-06-2012 10:01 AM
โOct-06-2012 09:40 AM
Not a theory...a simple fact. It's basic physics: 350HP is 350HP.
โOct-06-2012 09:36 AM
โOct-06-2012 09:22 AM
uncleluap wrote:427435 wrote:
Many of you are confusing force (torque) with power and work (hp) and need to re-take physics 101. Torque is the force on the axle TRYING to turn it. There can be a lot of torque on that axle BUT, if it is not turning, there is no movement of the MH and no WORK being done. When it is turning, there is WORK being done. The faster the axle turns, the more work (hp) is being done. Remember that a 1000 hp gas turbine may only have 175 ft-lbs maximum torque, but it is spinning at 30,000 rpm. And it will move a tank nicely and last a long time.
A 350 hp gas engine will do as much WORK as a 350 hp diesel engine. It may not last as long operating at max hp as a diesel engine, but that is due to design targets the engineers were given. The gas engine will also need more gear reduction to keep it in its peak hp rpm range.
so then in theory your claiming a 350 HP gas engine will power the
the 34000lb MH up a hill at the same rate and speed as the 350HP cimmins will? just operating at different RPM ratings?gas being 3X what the diesel is reving