Fuso at Altitude

Mock Tender

Adventurer
I have spent quite a few weeks this year driving in and around mountains and higher altitudes. I have been on dozens of passes over 10,000 feet. My highest on dirt/gravel unimproved roads was Hagerman Pass (11,925’) west of Leadville, Colorado. On asphalted roads it was Independence Pass (12,095’) east of Aspen, Colorado. At several places, we camped above the 12,000’ level.

I am in a 2015 Fuso: my weight is 12,000 pounds and I currently have 295 75R16 tires. The following would even be more critical with larger tires.

What I have found is there is a tremendous loss of power after 9000’ and the technique for driving has to change in the 10,500 feet and above.

On good paved surfaces, just by keeping your speed up, you should be able to crest most passes at the posted speed. If you have to stop, at over 10,500, make sure that you are on a flat or slightly descending spot. Don’t pull into an area where you have to ascend, right away, before you can get to at least 2-3 mph. Once rolling you are good.

For unimproved roads, at 10,500 and above, even flat surfaces may not work. I have almost been stuck when on flat dirt or where smallish rocks would not allow me to move.

Another thing is make sure that where you camp also allows some flat or descending area to get moving. Most of the nights at that altitude will get down into the 30’s or less. You just won’t get enough heat generation sitting there to help with a sluggish Duonic transmission.

And for those of you curious, the creep mode or manual is the only way to go in these situations.

Now having said all that- not many campers up at those altitudes. And the look on the Jeep, ATV and motorcycle crowd face’s are priceless. They can’t believe how we got there.

Another side note- at those altitudes and temperatures you will burn up propane rather quickly. You may also have problems lighting propane appliances. What I found that works, is to bend the brackets that hold the probes, to get them closer to where the burner is. Not the PROBE- but the bracket that holds the probe.
 

dlh62c

Explorer
Make sure your not in the Economy Mode under such conditions. The Duonic can get confused causing it to unwisely upshift causing the engine to bog.
 

gait

Explorer
some experience with 2005 FG649 manual. Above about 4,500m (14,750ft), dirt tracks, the turbo boost was low enough to turn engine warning light on. Lots of black smoke. Decided against retuning. Maintain revs, reduced power but always enough. Above 5,000m (16,400ft) on sealed highway, highway speeds, occasional low boost on uphills. Webasto diesel water heater model has auto altitude compensation, worked well.
 

Czechsix

Watching you from a ridge
Interesting, and I believe it.

We got above 9000' on our last trip, I didn't really notice a difference, but then again I've also got the tall gearing so that didn't help. One thing I did note when taking off up a hill in the automatic mode is that there was a considerable lag sometimes in the shift - the truck would almost redline. I just went to the manual mode and that worked fine.
 

Stitch

Member
Mock Tender, thanks for your post. I've been looking at the Fuso as a possible replacement for the current rig, so your report is very interesting.
 

unkamonkey

Explorer
I spoke of a loss of power at altitude in my Mitsu and my neighbor thought I was full of crap. The next time he drove across the mountains here in CO he felt that his manly Ford Powerstroke didn't have the same power either. OH?
Temps have a lot to do with it. If I hit Vail pass when It's cool still or in the winter I can pull the whole East side in 5th gear. The west side is a chore no matter when you do it. I'm off there with the semis. We can play well together. I respect them and they return the favor.
 

kerry

Expedition Leader
East side in 5th gear? How much do you weigh? I don't think I've ever made it up there in 5th gear. Maybe 4th. On the West side I've been down to 3rd on the steepest section. I'm almost 12k lbs.
 
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unkamonkey

Explorer
East side in 5th gear? How much do you weigh? I don't think I've ever made it up there in 5th gear. Maybe 4th. On the West side I've been down to 3rd on the steepest section. I'm almost 12k lbs.

It's been a few years since I weighed it but it was around 11,700 without a full load of water and food in it. What engine, transmission, gears do you have?

Yeah, the hog back, Floyd hill, Georgetown hill, heading up towards the tunnel from either side is done a few gears lower and I just stay in the right lane and follow the semis even if I might be able to do a few more MPH.

I was in Montrose in the middle of a hot summer day and even on flat streets, starting out from a light it felt like I had no turbo. I headed East and gained altitude and it also cooled down a fair amount. OK, I seem to be getting boost again.

Wolf Creek Pass with the Jeep on the back coming back from Durango, 3rd gear, 2300 RPM, 23 MPH. Stick your arm out the window and watch the scenery go slowly by.
 

pugslyyy

Expedition Vehicle Engineer Guy
I find that even as I gear down to go up the big grades, it's even more critical to keep an eye on the temperature gauge than the tachometer or speedometer. Crawling up grades becomes a thermal management issue for me more than anything else. I have to set a speed that allows the cooling system to function.

A lot of the time wind will be whipping up behind you as you climb, creating a low pressure pocket in front of the truck and reducing the efficiency of the radiator and fan even further.
 

unkamonkey

Explorer
I never have had much of an issue with temps until I was going to Lake Powell and heading into about a 30 MPH head wind at about 112 degree heat, level ground. Mine will squack at me if it thinks the coolant temp is getting too high. It starts out as an eh eh eh and will build to a steady tone if it gets much higher. Funny, the temp gauge hardly even moved, well below the red area. I limped into Green River UT for fuel and a guy in a car hauler had to walk over to look at my rig. I told him I was running a bit warm and he just told me to gear down.
I'm slow enough already.
I couldn't even scrape the dead bugs off of the windshield due to the hot wind.
I'm surprised how small the radiator is in these things, The radiators in my Jeeps are larger for a smaller motor.
 

kerry

Expedition Leader
4DBT 5spd manual. The engine has started to get hot near the tunnel eastbound on a couple of hot summer afternoons. Not overheating though.
 

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