Power loss due to altitude

[Boldt's Wagon]

As long as you don't see smoke, there is no loss. Higher altitudes will result in slower turbo spoolup and can smoke until the boost builds up.

 

[Joseph Donnelly]

Several years ago Dodge claimed 0. 5% per 1000 ft altitude for the Cummins.

 

[B.G. Smith]

I didn't really notice much power loss at higher altitude(Leadville Col. 10800')but did have some smoke on take off. The turbo was screaming for air at that alt. bg

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White 99 3500, QC, 3:55, auto. most options except leather, Line-X bed liner, fiberglass running boards Rancho 9000s, bug shield and window vents, black vented 5th wheel tailgate, 100 gal. aux. fuel tank.

 

[KevinK]

I haven't had a chance to try the truck over any passes yet, but it's good to hear that power doesn't drop off much. I'm sure that there isn't as much air entering the engine higher alitudes, because we definitely have higher EGTs up here. Less air means less power, but I guess that as long as there is enough air to burn the fuel, it isn't an issue.

 

[LSMITH]

This is where the bigger turbine on the turbo comes in. The small turbo cannot move enough air to get the manifold pressure at altitude. The bigger the turbine the more air it can move, but it takes longer to spool up. This is why the Cummins will make sea level power up to about 9500' and the PSD and GM 6. 5 start to lose power at about 5000'

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99 2500 QC 4X4 AUTO SB 24V LARAMIE SLT 3. 5 LSD 285-75-16'S

 

[KevinK]

I had read a letter in Trailer Life about a guy who was down to about 3mph pulling a 5th wheel over Monarch Pass (~11,000 ft) using a PSD. I was a little worried that the Cummins would have the same problem.

 

[Bart Timothy]

I've had my ETH/DEE pulling a 24' TT, up over both the Top of The World Drive on the northeast end of Yellowstone heading toward Red Lodge Montana, and over the Rocky Mountain National Park in Colorado. Both those roads are over 12000 ft. There wasn't much power loss that I could tell with either drive once the turbo spooled up.

By the way, if Rocky Mountain qualifies as a national park because of the drive, heaven only knows what Top of The Wold Drive must qualify for.

[This message has been edited by Bart Timothy (edited 01-14-2001). ]

 

[Fireman Dave]

A little off the topic, but I saw you mountain guys on this one, so here goes. I'm planning on a trip west this summer. I'll be towing through the mountains. When I was out there a few years ago, my 3. 3L V-6 kept puking coolant (to a point) out of the overflow due to the altitude. I kept refilling, and it kept puking. I finally waited until I got down to Nebraska to top it off for good. My question is, what should I expect with the Cummins in high altitude? Do I need to take any special precautions to prepare for the altitude?
Thanks

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2001 2500; SLT; 4x4; QC; LWB; Auto; 3. 54 LS; 265s; Camper; Tow; Sliding Rear Window; Travel Convenience Group; Cab Clearance Lamps; Forest Green

[This message has been edited by Fireman Dave (edited 01-14-2001). ]

 

[LSMITH]

Dave, if you have never driven the Cummins in the mountains you are in for a real treat. I grew up in SW Colorado so I go back at least once a year. The truck is like no other vehicle in the world. Once the turbo spools up the roads get flat! The sensation of full tilt acceleration up a 7% grade is awesome. No preparation necessary, but you may want to smile a lot in the weeks before so your face doesn't get sore.

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99 2500 QC 4X4 AUTO SB 24V LARAMIE SLT 3. 5 LSD 285-75-16'S

 

[DavesDodge]

Fireman-I second LSSmith. I see some smoke from mine on rare occasions when bashing around on a high trail, but I love surprising PSD's when I zip on around 'em at 10-12,000 feet! Great! Just pay attention to starting procedures for the truck if it is cold. #ad


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2001,2500,QC,SLT,4x4,
Cummins HO,6 spd. ,3. 54 gears,SBox,Dark Garnet/Pearl, all options but leather/snowplow/Sport, the elusive front license plate bracket,"Cup Smoothie" Autometer gauges on A pilar, LineX bed liner, Cobra CB,Westin nerfs, Power tailgate lock,auto on/off headlights, backup alarm, real backup lights. More To Come! Big Dog on the Mountain! Engineer Pass,Co.

 

[Fireman Dave]

Thanks, guys. How about the coolant - will there be any puking? And Howard, I have to work tomorrow, so I can't stay up late on here with you again tonight. #ad

 

[LSMITH]

No coolant puking on mine. Just fun!

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99 2500 QC 4X4 AUTO SB 24V LARAMIE SLT 3. 5 LSD 285-75-16'S

 

[B.G. Smith]

No problems with losing coolant. You must have had a defective radiator cap(too low pressure) to cause it to blow the coolant out.

 

[johnrv4]

I drove mine up to the top of Pike's Peak and the only thing it puked out was gear oil out of the front differential breather tube. #ad
#ad
I've had it through the mountains of Colorado, Utah, and Wyoming when the temps have been high and never had it puke any differential fluid.

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2001. 5 2500 Quad cab SLT 4x4 ETH/DEE, towing package, snow plow prep, 3:55 anti-spin, and other goodies. Flame Red

 

[KevinK]

Does anyone know what the percentage of power loss is per 1000 of elevation feet for a Turbo Diesel? I'm sure it's not as high as a non-turbo (~3%/1000 ft. ), but there must be some known amount.

Thanks,
Kevin

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2k 3500, QC, 4x4, SLT+, auto, 3. 55s, 4" exhaust w/muffler, 14sq. cm Holset turbine housing, Westach gauges (EGT, Boost, transmission)

 

[highland]

Drove mine up Pikes Peak last summer (Dirt road - steep grade to 14,000 feet). The power was great! So good, in fact I couldn't resist slpping into 4wd and passing a few cars (& trucks) on the way up. In 4 wheel drive it will flat out scream up that mountain regardless of altitude!! I did not notice any drop in power - but I did notice a little drop in ability to cool the motor in the thin air when your getting on it comming out of every turn.

 

[Happy Camper]

Took Monarch pulling a 30' 5vr using a 2500 Ram. I was running anywhere from 30 to 40 staying out of pedal to the medal. No problem. If it got down to only 3mph and that would be all it had, I would kick it out of gear and tell my wife to JUMP and collect insurance money. #ad
: It was a 5spd manual. With the Cummins you will not have to worry about pulling poser!

 

[DavidD]

Kevin, Great topic! When i waas test driving trucks I had the benefit of a 7500' mountain pass right by the dealerships(ford&dodge). I took a psd out and drove up the pass then a dodge, what a dif. The dodge was so much more responsive and would accelerate up the hill. I live at 5000' and routinly travel over 8500' on mountain roads towing a 3 horse trailer its incredible to pass cars on the passsing lanes. what fun! with the truck empty coming back from the bay area over carson pass (8400') it will pass just about anything on the road. the thruck now is slightly bombed(power mod. ex, and e-brake,with 9's atthe four corners and 315's for added handling and traction)but still pulls 18mpg aver. Have fun in the mountains but remember the brakes are the trucks weak point(why I installed an exhaust brake) Good Luck!

[This message has been edited by davedd (edited 01-15-2001). ]