F11Engineer

In about 2 months I'll be new to diesel ownership (ordering my 2500 4X4 tomorrow). ;D ;D ;D<br><br>This summer I'm planning to tow 5000# around the Colorado Rockies. Anyone have any tips for a noobie on differences driving a diesel at higher elevation? What about gotcha's to look out for? <br>I've got plenty of experience towing with gas engines, but the last few months reading this forum leads me to believe a diesel is a different beast and there may be a few things I ought to be aware of in advance instead of learning about them on the road! <br><br>Thanks.

StakeMan

Turbo spool up will be slower and smoke will increase as you climb in altitude. Watch your EGT's because there is less oxygen for the same amount of boost.

03quadduallyho

The smoke etc stuff sure was true about my old F--d diesel, even though it was a turbo etc it really got up the smoke quick and heated up the EGT really bad on the high elevation hills, with the new HO cummins I have, I have been into the mountains in CO/ WY and have not experienced a single condition while towing that the smoke became even visible out of the tailpipe. I think the capacity/output of the turbo is really well setup for the engine and I haven't even experienced a single change even at relatively high altitude other than just a solid hill and a strong pull all the way up. Towing a 5000 pounder you should be better than fine, you have probably the best vehicle to tow with. I forgot to check your signature, but for mountain work I would recommend the 6 speed for aided engine breaking and slightly more controlability of the tow, but that is just my humble opinion and I'm sure that the auto boys will say something in opposition. Enjoy probably the best truck you can or could get in 2003 at least. Best wishes, Monte<br><br>PS, I think an exhaust brake would be a good investment.

Bluedresser

Just towed and 8500# racecar trailer from Carson City, NV to Phoenix and back. Starting at 4800' in Carson City, we climbed over 8000' mountains and down to sea level before getting to Phoenix that is about 1200'. I drive at speed limits, but do not exceed 65 mph as I feel that is the safety speed for my trailer. Never had to drop below 5th gear - found that as soon as the speed dropped even 1 mph below 55, I would shift down to fifth - and averaged 14+ mpg round trip. I also have a jake brake and couldn't live without it. Hardly used the brakes at all until below 20 mph (except to show the brakes to let cars behind me know I was slowing down). You'll love the ctd.

Vaughn MacKenzie

F11Engineer, one nice thing about a Cummins TD at real high elevation is you will literally fly by all those wheezing gassers trying to make it uphill on thin air ;D ;D<br><br>Vaughn

Casey Balvert

[quote author=StakeMan link=board=20;threadid=12216;start=0#115542 date=1047584546]<br>Turbo spool up will be slower and smoke will increase as you climb in altitude. Watch your EGT's because there is less oxygen for the same amount of boost.<br>[/quote]<br><br>Actually the percentage of oxygen in the air remains relatively the stable at altitude. Only the pressure is less. If you increase the pressure (ie. boost) the amount of oxygen the engine is getting is the same as sea level at the same boost pressure. That is the whole idea for putting turbochargers on these trucks. Just my two cents.<br><br>Casey

StakeMan

Less oxygen for the same amount of boost.

GrandpasRam

Monte - get the Ebrake. Just had mine put on yesterday (ordered it with the truck but it was on backorder for awhile), and it makes a noticeable difference. If you are going to spend any real time towing, it is even more worth the expense.<br><br>Casy - Oxygen is one of the heavier gasses in our atmosphere, therefore stays lower in elevation than the lighter gasses (like Hydrogen, Helium, Argon, etc.). At elevation, the turbocharger is to get the same VOLUME of air as at sea level, but the O2 content is still a little lower. FWIW

Bluedresser

The amount of all of the gasses in the atmosphere remain the same at any altitude. The thing that differs is the amount of any of the gasses in any given volume. The higher you get, the less gas per volume, which is why as you get higher a person needs to put on an oxygen mask in order to get enough oxygen to live. For example. Most airline cabins are pressurized so that the cabin altitude is about the equivilent of 8000 to 8500 feet above sea level. That is why oxygen masks will fall out in the event of cabin deprssurization. You will need the supplemental oxygen until the cabin pressure falls back below 10000 feet. The higher the truck climbs, the less oxygen it will get per cylinder volume unless you supercharge or turbocharge it which then packs more air (which is compressible) into the existing volume.

StakeMan

Still have less atmospheric pressure to help the turbo.

Bluedresser

This is very true, for example, turbocharged aircraft engines begin to run out of steam above 25,000 feet or so, but we don't have to worry about that with our trucks as roads don't go that high where most of us drive, so we'll continue to have the necessary boost for all of our needs.

Vaughn MacKenzie

The higher you go the longer it takes the turbo to spool. Less air volume per engine revolution and therefore less air to spin the turbine.<br><br>The higher you go the less max possible boost you will achieve (for the same basic reason indicated above). Another thing that will happen is you will have less HP at 30psi boost reading when you are at say 10,000 feet compared to 30psi boost reading at sea level.<br><br>Here's why:<br>14.7psi @ sealevel + 30psi boost = 44.7psi absolute<br>10.1psi @ 10,000ft + 30lbs boost = 40.1psi absolute<br>therefore. . . <br>You make 300hp at sea level @ 30psi indicated<br>You make 270hp at 10,000 feet @ 30psi boost indicated<br><br>You just lost 10% of your air &amp; horsepower even though your boost gauge reads the same. Be glad you're not a gasser though, at 10,000 feet a whopping 31% of your air and horsepower went bye-bye!! :'(<br><br>You lose .49psi air pressure for every 1000 feet of elevation increase. <br><br>Try driving to the top of Pike's Peak. 14,110 feet. Did it once, and my dad's car and no oooomph whatsoever. Ambient air pressure drops all the way down to approximately 7.8psi! That means a 300hp Cummins will drop to 254hp and a 300hp Corvette will be reduced to a wheezing 159hp!!! <br><br>Vaughn<br>

StakeMan

The turbo will also spin faster to create the same amount of boost. I think those turbo charged airplanes have to watch turbine speed. I could be wrong though.

P Kennedy

Vaughn good tech info, helps explain what people living at increased altitudes work with all the time. F11 Engineer you are driving a superior vehicle for pulling at higher altitudes as long as you stay stock and watch the water temp. To much much talk on here emphasizing EGT's when the engine ingeniously tells you a lot by the water temp. If you begin using power enhancing toys a full set of gauges is truly important. Simple trucker rule, if the water temp does not cycle within the operating zone along with fan (190-205F) back out of it and climb the hill in lower gear. If the unit refuses to drop temp and is over 210F find a pullout right away and run engine at 2000-2500 rpm, open hood so hot air can be evacuated quicker through the radiator. Remember these trucks have 2 other rads, air to air cooler,A/C cooler in front preheating the engine rad. If the water temp is staying too hot the oil cooler built into the engine can't maintain the oil at a respectable level and it will start to decompose. DO NOT shut off a hot engine unless absolutely can't be avoided, heat rises and all the heat will go into the head and warp it, turbo could coke the oil in the bearings and for sure if it has not boiled over it will then. PK

Mexstan

Hey guys. Have to say I am impressed with the level of technical expertise here. Vaughan, hats off to you as you are spot on.<br>My Infiniti I30 at sea level burns rubber easily. In fact have to watch I don't inadvertantly burn rubber on fast starts. It is normally aspirated. At 7000-8000 feet where I live it is still peppy but will barely burn rubber even if I try.<br>My CTD on the other hand does not not appear to notice the difference between sea level and 8000 feet. No guages yet but as soon as I install them I can watch for any differances any report back if I notice anything drastic.<br>BTW Stakeman, as a pilot who has flown turbo-charged aircraft, have never seen a plane with anything to monitor turbo speed. On some of the older A/C there is a manual waste gate control.