A3 and altitude question.

[todds112]

I've seen pics of the label on the A3's engine that says, "8500 feet max". What happens over that altitude? What if they are run regularly below, but close to that?

Does the A2 multi-fuel have altitude restrictions? Is there an adjustment?

 

[Westech]

Fuel rate settings are critical to efficiency of diesel engines. MSHA specifies a fuel setting and a fuel deration curve for each engine during the approval process. The fuel deration curve is intended to ensure that the fuel rate does not exceed the maximum allowable at any altitude.

looks lie it might need a fuel adjustment.. But I would think you will be ok.. the rating is EPA stuff by the sounds of it.

 

[gimpyrobb]

Just slap in a turbo...

 

[stumps]

I've seen pics of the label on the A3's engine that says, "8500 feet max". What happens over that altitude? What if they are run regularly below, but close to that?

Does the A2 multi-fuel have altitude restrictions? Is there an adjustment?

The engine won't care, it will just wheeze, lose HP, and blow smoke. Mountains are a large part of the reason that turbochargers became a must have item on diesel trucks. A truck that was setup at sea level would smoke like a choo-choo in the mountains.

-Chuck

 

[garp]

MSHA doesnt have anything to do with the rating of a diesel engine unless its in an underground mine. Max altitude is a given figure that states the engine will produce XX hp and XX ft lbs torque up to that altitude. Since we are talking a mechanical engine it is a ball park figure that will vary between most every engine. An electronic engine will actually derate itself upon reaching the set alt. limit. Each varies but usually its 5% per 1000ft. A mechanical engine will simply puff a little more smoke. No problem.

 

[mudguppy]

The engine won't care, it will just wheeze, lose HP, and blow smoke. ...

...A mechanical engine will simply puff a little more smoke. No problem.

that's not true: these trucks are set up so that soldier A can drive around at max load with his foot buried to the floorboard all day. there is a ceiling because there is no EGT guage and no expectation that soldier A will ever take his foot out of it, especially at high altitudes.

8500ft is very high altitude for a diesel. run that thing like you stole it while above that altitude and you will burn it up. thinner air means that the turbo can't pack as much air into the engine which raises EGTs. turbos can't 'create' air if it isn't there; they are sized accordingly and can't do more than they have the capacity to do.

 

[stumps]

that's not true: these trucks are set up so that soldier A can drive around at max load with his foot buried to the floorboard all day. there is a ceiling because there is no EGT guage and no expectation that soldier A will ever take his foot out of it, especially at high altitudes.

8500ft is very high altitude for a diesel. run that thing like you stole it while above that altitude and you will burn it up. thinner air means that the turbo can't pack as much air into the engine which raises EGTs. turbos can't 'create' air if it isn't there; they are sized accordingly and can't do more than they have the capacity to do.

I am remembering back to my family travels through the mountains back in the late '50s and early '60s. Turbos were non-existent on diesel trucks. And they smoked furiously as they climbed the switchbacks... at 25-30MPH.

To burn up a diesel engine, you need to make fire. You need lots of air to burn enough fuel to overheat the exhaust system, and to burn the valves. In the rarefied atmosphere above 8500 feet, there isn't enough air to burn the normally allowed amounts of fuel. Diesels just make soot.

-Chuck

 

[mudguppy]

...To burn up a diesel engine, you need to make fire. You need lots of air to burn enough fuel to overheat the exhaust system, and to burn the valves. In the rarefied atmosphere above 8500 feet, there isn't enough air to burn the normally allowed amounts of fuel. Diesels just make soot.

-Chuck

chuck, go plug your deuce's intake and drive around w/ your foot on it and report back. or do this on your PSD, Cummins, or Dmax and let me know how that goes.

what you're ignoring is that if you are making black smoke, the fuel has already been burnt. you can't "make soot" w/out burning the fuel!!! if the fuel is burnt, then there is obviously enough O2. now if the exhaust is gray, then there isn't enough O2 to burn the fuel. [people often say "black smoke is wasted fuel" - that's not true!!!]

so if you've got the fuel burnt but are starving it for air, you're just creating heat. the job of the turbo is not to simply provide more O2; the air charge also cools the combustion gases. same reason you introduce aftercooling.

example: i've got enough fuel moving through my 5.9 Cummins for 400hp. but my stock turbo doesn't move enough air to keep that cool. so when you jump on the 'go' pedal it smokes like a freight train. it's running, it's burning the fuel, it's not flooding and extinguishing the flame. but my EGT guage will bury into the 1600° peg in about 3 seconds - i don't have enough air to keep the combustion cool.

oh, and your valves will likely be the last thing to go.

 

[saddamsnightmare]

November 19th, 2009.

Todds112:

Yet there had to be some realization that these trucks might have to work at high altitude when they were initially designed.....? If you check youtube and look for the one on the Macchu Pichu Railroad line, you will find that their diesel electric locomotives are able to climb to extreme altitudes with a train because they have turbo chargers. If you were to run the truck at extreme high altitude, you might have to switch turbos or go to a turbosupercharger, like was done on the B-29 engines so they could function at extreme high altitude. The unfortunate thing, is the deuce is so unsophisticated that there is no computer to derate or compensate for the high altitude operation on the stock trucks, so you're gonna have to get off the pedal and accept slower, more inefficient operation if you want to save the engine.
Just my twio cents worth,

Cheers,

Kyle F. McGrogan

 

[Keith_J]

Diesels typically run with far excess air for the fuel injected. This cools the exhaust through dilution.

Climb to 8500 feet above MSL and the atmospheric pressure is 2/3rds sea level so there is 1/3 less air. But the fuel rate is determined by the right foot of the nut behind the steering wheel.

So yes, in a non-turbocharged vehicle, you can have problems. Turbocharged vehicles have less of an issue but unless they have a density altitude compensating control, they may not be able to fully compensate. Turbines are driven by heat, with less atmospheric pressure, there will be more heat so they tend to self-compensate, if designed correctly. But they still can overheat.

 

[zout]

Not enough oxygen - reminds me of watching a National Finals Rodeo - guy riding the bull called "spinner" nails the rider to the ground within milliseconds after the gate flicks open - rider smashed horribly into the ground all buckled and mangled - totally knocks the wind out of the rider - announcer comes on and says " all the oxygen in this arrena - and he can't get non".

 

[todds112]

I figured there had to be a trade off. I've never owned a diesel, so I'm still learning the principals. Now on my gas/air cooled Pinz I just rejetted the carbs for higher altitude and it runs just fine up here. I'm sure it has less power than at sea level, but I've never driven it anywhere else, so I have no comparison.

I know even with computer controls, my Jeep Rubicon struggled going over some of the 12,000' plus passes in Colorado.

A duece living here would spend it's life at 6500' minimum to 10,000'. Don't want to get one if it's going to blow up inevitably.

 

[zout]

todds - wanna see that truck huff and puff - take er over Wolf Creek Pass huh

 

[Chief_919]

We ran A3's up over 10,000ft in Afghanistan. the power loss was very noticable, but we got where we were going.

 

[todds112]

todds - wanna see that truck huff and puff - take er over Wolf Creek Pass huh

I can imagine. My Jeep was floored and doing about 45-50MPH over Wolf Creek. Going over Teton Pass here (9% Grade, 8500') my Pinz would go about 25MPH Max. Wondering what a Deuce would do?

 

[Blacksmoke]

todds, if you're gonna get one, put a pyro in it & then you can monitor your egt. I have one in mine & with the pump turned up a little, I can hit 1200 degrees easily (a flatlander in the midwest). You just have to watch it & back out of it if the egt gets too high. Egt runs highest at heavier load with lower rpms - less air flow. Where you will do the damage to your pistons is if you hit a high temp for a prolonged time.

 

[stumps]

chuck, go plug your deuce's intake and drive around w/ your foot on it and report back. or do this on your PSD, Cummins, or Dmax and let me know how that goes.

I've done that with heavy construction equipment, and dirty air cleaners, and all I have noticed is the digger gets slower and slower, and the smoke gets thicker and thicker... So I wash the air cleaner, and we are back in business. I haven't seen any sign that the engine cared at all... but of course, diggers are designed for longevity, and are not pushing the envelope.

what you're ignoring is that if you are making black smoke, the fuel has already been burnt. you can't "make soot" w/out burning the fuel!!! if the fuel is burnt, then there is obviously enough O2. now if the exhaust is gray, then there isn't enough O2 to burn the fuel. [people often say "black smoke is wasted fuel" - that's not true!!!]

Black smoke is incompletely burned diesel fuel. Incompletely burned fuel is another name for wasted fuel.

White smoke is unburned diesel fuel. It typically has nothing to do with a lack of air, and everything to do with a lack of heat. The lack of heat could be because of ambient temperature, poor compression, incorrect injector timing, or a broken injector...

so if you've got the fuel burnt but are starving it for air, you're just creating heat. the job of the turbo is not to simply provide more O2; the air charge also cools the combustion gases. same reason you introduce aftercooling.

example: i've got enough fuel moving through my 5.9 Cummins for 400hp. but my stock turbo doesn't move enough air to keep that cool. so when you jump on the 'go' pedal it smokes like a freight train. it's running, it's burning the fuel, it's not flooding and extinguishing the flame. but my EGT guage will bury into the 1600° peg in about 3 seconds - i don't have enough air to keep the combustion cool.

I have a friend who says, you aren't racing if you aren't breaking parts... I don't race, and I rarely break parts. If that were my 5.9 Cummins, I'd turn the fuel down to something safe... but then I really hate fixing things that were broken needlessly.

oh, and your valves will likely be the last thing to go.

Nice to know. I have always had the feeling that diesels run ice cold compared to gasoline engines.

-Chuck

 

[jollyroger]

My .02. I live at 5700 feet. I visit family that lives at 8500 feet. I have to go over a pass that is 11000 feet. I hunt in areas that are 11000. It has been my experience that one burns up their dieses in these mountains when they let the diesel lug it out with the foot feed to the firewall. All my diesels I have put an EGT guage on except my new Dodge and my Deuce. EGT Guage is pending for both. It is an invaluable tool for keeping your motor together considering the grades and altitudes here. What we did before Ford recognized the need for high altitude injector pumps on the 6.9's in the 80's and before we had good EGT guages was to have a spot mirror pointed at the exhaust. We backed off the throttle until the black cloud diminished. We continued to do this after the high altitude pumps were installed even though the trucks ran a lot better. This is what I'm doing with my Deuce right now. And yes. They lose a ton of power above 8500 feet. I go to low range pulling Berthoud pass with my Deuce so I have some gear selection. I could only get 20 MPH out of it at the top before I put on the 395's. I don't know where I'm at now. I am looking for an LDS motor to drop into it. I think that will be about as good as it gets for me.