can a 6.2 really do this

[84CUCV]

some kid i meet. said his built 6.2 with a sm465. went right up something that was just about vertical. at idle. dont see how that could?? could it?

thanks just wondering

 

[DEMON44]

of course it is, the governor controls minimum idle and adds fuel when load is met to maintain min engine speed. operator has no control over that. with the gear ratio involved and enough traction, it wouldn't even be breaking a sweat pulling itself up something. Hookup to a 20,000lb trailer sometime on a hill and let out the clutch...don't touch the throttle. you'll be amazed at what a diesel can do in low at idle.

 

[84CUCV]

wow ok cool

 

[imiceman44]

some kid i meet. said his built 6.2 with a sm465. went right up something that was just about vertical. at idle. dont see how that could?? could it?

thanks just wondering

Yeah the SM465 with it's low gear that is more than twice the ratio of the auto low gear with the diesel idle control it can.
I wheeled my K5 with a diesel all the time with no gas pedal action, just let it idle over 5' boulders, as long as my bumper cleared it it went up no problem.

 

[84CUCV]

wow cool thanks

 

[tRustyK5]

I wheeled the first half of Pritchett Canyon without ever touching the gas pedal. Having a governed idle, manual transmission and traction it's crazy what it'll do at idle. It makes "wheeling elegantly" so easy...

Rene

 

[84CUCV]

ok thanks rene

 

[kennyw]

Only thing that will stop you on a vertical climb is running out of oil pressure...

 

[tRustyK5]

Usually traction becomes an issue before that. With the pick-up at the rear of the pan it's the steep downhill sections that can lead to no oil pressure...but it's gotta be damn steep for that to happen.

Rene

 

[84CUCV]

ok thanks

 

[6.2Blazer]

The hill might of been steep, but guarantee is was nowhere near vertical. Vertical is 90 degrees, and even with a very grippy surface most vehicles don't have the traction to crawl a much steeper grade than maybe 45-50 degrees.

 

[imiceman44]

The hill might of been steep, but guarantee is was nowhere near vertical. Vertical is 90 degrees, and even with a very grippy surface most vehicles don't have the traction to crawl a much steeper grade than maybe 45-50 degrees.

Actually if he's talking about just the front tire, i have seen plenty do that, the rear would still be going on flat and helping with raction against the vertical section.
I have seen rigs climb on a pole.
Granted it's only a few feet up the pole but it still is vertical.

 

[84CUCV]

your right. one tire on it other three down.

 

[6.2Blazer]

Actually if he's talking about just the front tire, i have seen plenty do that, the rear would still be going on flat and helping with raction against the vertical section.
I have seen rigs climb on a pole.
Granted it's only a few feet up the pole but it still is vertical.

Guess I should have specifed "all four tires on the grade at the same time". Sure, if it's a 1' high berm than it's a whole different story.

 

[imiceman44]

The hill might of been steep, but guarantee is was nowhere near vertical. Vertical is 90 degrees, and even with a very grippy surface most vehicles don't have the traction to crawl a much steeper grade than maybe 45-50 degrees.

hey if we want to be technical, 50 dgerees is actually not feasable unless the tires are made of glue, 45 is the most you can get traction enough to move uphill

 

[kennyw]

I'm gonna make my tires out of geco's feet so I can drive up a vertical wall someday...

 

[6.2Blazer]

hey if we want to be technical, 50 dgerees is actually not feasable unless the tires are made of glue, 45 is the most you can get traction enough to move uphill

What rationale are you using for this? Presumably the idea that at 45 degrees the force the vehicle has to overcome to go up the grade is equal to the weight of the tires on the slope? On paper this makes some sense, but it's not accurate to real world conditions. We have a measured 60% (apprx. 55 degree) concrete slope at work and you can indeed drive up it in certain vehicles (the surface is a very grippy brushed concrete). 60% is a fairly standard gradeability spec for military vehicles and such.

 

[mudman83]

*Editted*

At 45 degrees the force pulling the truck toward the slope is equal to the force pulling down the slope. So you still have traction. In fact there is always some amount of traction untill the wall is vertical, then all the force pulls down and nothing is keeping you against the slope. Now if that traction force is great enough to overcome the force pulling down the hill depends on the coefficient of friction(static or kinetic depending on the situation), and other things like imperfections on the slope(rocks, ledges, ruts). The equation for friction is:

force friction = coefficient of friction * normal force(force toward the hill)

So the friction force must be greater than the force pulling down the hill to move you to the top.

There are coefficients of friction over 1, so only considering friction it is possible to go up a grade greater than 45 degrees.

However when tires conform to rocks and ledges, they become like gears or levers where friction is not the only thing involved. Now the force fighting the force pulling you down the hill is even greater. That is why we air down.

So in certain cases 45 degrees isn't too difficult to climb.

 

[84CUCV]

thats sad. that confused the heck out of me.

 

[mudman83]

Okay I tried to fix it to make more sense. I am not very good at explaining things hopefully this is better.