Oil & Fuel Diesel torque difference mostly myth?

[jpr62902]

Another distinction is that the diesel will produce much greater torque throughout a much broader range of RPM's, while the gas engine needs to be at higher RPM's constantly to generate it's torque.

 

[Bob_Skurka]

Just an observation here. You guys can debate all the technical aspects of this until all of Getut's coworkers fall asleep from bordem, or you can do it my way, sell tickets to the event to raise money for charity (or just to pay for the beer), and all have a lot of fun (er, all but one guy I suppose) /forums/images/graemlins/blush.gif

JMHO

 

[SnowRidge]

<font color="blue"> On the exact same engine the higher the RPM and/or the higher the compression, the shorter the lifespan will be. </font>

On the exact same engine, everything will be the same -- inlcuding the type of fuel. You are trying to do an orange to orange comparison with an orange and a persimmon. /forums/images/graemlins/blush.gif

 

[getut]

/forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

Wow.. typing statements bite and oh how you can be misunderstood.

That statement was not differentiating between fuel types.. it was simply stating that on a given engine... any engine, the higher RPM and/or compression it is running at, the less its lifespan will be.

 

[SkyPup]

Fill this form out exactly and turn it in to the ME Professor and if you answer the questions on Page #3 stating that your gasoline powered identical displacement engine produced more BMEP then you earn an "F" in mechanical engineering.... /forums/images/graemlins/shocked.gif



http://www.me.umn.edu/education/courses/me4431/Handout%20Diesel%20JD4045.doc

 

[SnowRidge]

<font color="blue"> Another distinction is that the diesel will produce much greater torque throughout a much broader range of RPM's, while the gas engine needs to be at higher RPM's constantly to generate it's torque. </font>

Somewhere from the cobwebs of my mind, I remember reading an article about this very point. As I recall, one way to do the comparison was to compare the area of the graph under the torque curves -- or was it the HP curves. Hmmm, it seems I forget which it was. /forums/images/graemlins/confused.gif

Must be getting old. /forums/images/graemlins/mad.gif /forums/images/graemlins/grin.gif

 

[BB_TX]

<font color="blue"> believe an expert </font>
That is nothing more than a slick sales and marketing campaign. No real comprehensive head to head comparison data.

 

[tillboy2001]

I'd say there's a slight difference in torque on trucks at least /forums/images/graemlins/wink.gif Using a 6.0 GM 'Vortec' gas engine compared to a 6.0 Ford 'Powerstroke' diesel. Diesel wins by far...

Horsepower (SAE net@rpm)
6.0L GM GAS = 300@5,000
6.0L FORD DIESEL = 325@3,300

Torque (lb.-ft.@rpm)
6.0L GM GAS ENGINE = 365@3,750
6.0L FORD DIESEL = 570@2,000

 

[getut]

Wow Skypup.. you seem to be taking this personally.

I did not say gas was superior. I said diesel still wins.

But the normally aspirated, small diesels, with short stroke and high RPM do not have nearly as big an advantage as one normally thinks when they hear diesel. In fact, the small advantage that is left is only due to the higher compression and slightly higher potential energy per ounce in diesel fuel vs. gas.

You keep changing the scope of what I am saying.

 

[getut]

PZ... you are correct, but look deeper. I guarantee you that even though the displacement is the same, I bet the stroke on the diesel is much longer than the gas engine.

I am talking about the nullifying effect of building the small diesels with short stroke that turn nearly the same RPM as their gas counterparts. The torque advantage is very small and is the basis for me starting this thread (and wanting to discuss it).