Diesels at high and low altitudes..

[BTDT]

Has anyone found their tractor to operate differently (running wise) at different altitudes? Is this something that is done at factory i.e. different injectors/pressure settings for different parts of the country or does it matter? I know a 2 stroke motorcycle from Dallas wouldn't hardly run on the coast (Corpus Christi).

 

[Logan]

I don't know the difference in altitude between the coast and Dallas but I have my home in South GA at an altitude of about 200 feet. My cabin in NC is at an alt. of 3,000 feet. I can't tell a difference.

 

[DieselPower]

With a electronic engine probably not as it will compensate for the preasure difference using the MAP sensor reading. Non electronic engines, yes. There is less oxygen at higher altitudes. The higher you go with a mechanical engine the less power it will have.

 

[SkyPup]

Every internal combustion engine, including all diesel and gasoline engines, that rely on atomspheric oxygen will lose about 5% of power for every 3,000 feet in elevation, doesn't matter if it is electronically operated or has a MAP or MAF sensor to correct for the loss of oxygen. The only way to correct for this loss of atomspheric pressure is to use a turbocharger, even that is not 100% though.

 

[RockyMnt1]

Yep. I have less power (about 6-8% at 8500 ft MSL) than you folks down by the big ponds, but I use less fuel/hr at a given RPM than you do, since fuel is mixed as a ratio to O2!!!

I haven't noticed the lack of power in anything that I have attempted with the tractor yet.

I am still trying to figure out how to hook up a blower so that I get "More Power" out of my tractor!!!! The turbos that I am familiar with (aircraft) turn at about 18,000-20,000 RPM (not a typo). They glow red it is so hot. I have to let them spin down at idle to avoid coking the oil and cooking the turbo bearings.

If you really want to see the difference between a turbo powered and normally aspirated vehicle, go to the Reno Air races next Sept. The turbo power planes lap the non-turbo planes. Of course, the turbo powered engines run hotter and don't last as long due to the stresses and internal forces, but they sure go fast.....

 

[SkyPup]

My two Garrett oil cooled Variable Nozzle Turbocharger compressors (VNT17) on our turbodiesels are maxxed out at 20 psi @ 210,000 rpms.

And yes, they do glow orange to red under load but we never have to worry about coking the bearings or cooling them down, since as soon as you take your foot off the throttle they immediately cool off. They don't begin to glow until you've had them at 8-10 psi for a few minutes under load.

When you do take your foot off the throttle, the exhaust gas temperature immediately falls from 1,150-1,200 *F down to 400-550 *F within two seconds.

 

[DieselPower]

"18,000-20,000 RPM (not a typo)"

That seems way to slow for a turbo speed. Sure it's not a typo? Maybe 180,000 to 200,000 RPM. I wouldn't think a turbo would be making much of a breeze at those speeds much less any boost. Are they that different than diesel turbo's?

"our turbodiesels are maxxed out at 20 psi @ 210,000 rpms"

Kind of slow for a performance turbo isn't it? Factory turbo's on Cat and Cummins road truck/tractor turbo's are around 250,000 rpm at max boost.

 

[KICK]

was going to add that Factory turbo on Detroits runs up around 120k rpm.
beyond that you get a turbo overspeed code.
aint sure what they hit on our Cumins ISM's, but I dont supsect its any higher than that.
these engines both run around 26 psi boost.
detroits use a barometric presure senser to get a altitude or air presure reading, along with boost pressure, air temp and the other nine or ten sensors.

had an engine that had a barmetric pressure sensor out of whack, doesn't set a code because it is reading, just telling the engine that it had 10 psi atmospheric, while at sea level. was a dog. never ran into that before, never even thought about until we had tried everything else and I noticed that and thought baro was somewhere around 14.7.

 

[SkyPup]

"18,000-20,000 RPM (not a typo)"Factory turbo's on Cat and Cummins road truck/tractor turbo's are around 250,000 rpm at max boost.

What make and model number are the turbocompressors on the Cats and Cummins that you are talking about?

 

[orezok]

I've been pondering this and though I'm no expert, there seems that there would be a difference between gas and diesel engines. All engines lose power at altitude, but I think diesels would lose less. Gas engines have to run a a very narrow fuel to air ratio (about 15:1). Diesels, because they run unrestricted have a very wide ratio from 100:1 at idle to ??:1 at full power. Given this information, it would seem that the diesel would maintain it's full power up to a higher altitude when the amount of air falls below it minimum F/A ratio.

Hmmm...