Planning to tow my 10,500# 5'ver thru Nebraska and Montana on I-90 with my F250 6.2 with 3.73 diff. I have read that my power loss could be 18% at the 6,000 ft elevation. Question is what will be most noticeable during that much power loss? Will the truck simply stay in a lower gear longer than at say 2,000'?Also with thinner air will the truck computer call for less fuel to accommodate the reduced oxygen?

 

I can not give you an exact answer. With our truck camper we were at full payload capacity. Much less than the effect of your fiver I know, but we ran that same route and my impression was the truck ran about one gear lower and stayed in it longer than at lower elevation. No real significant impact in terms of driveability, but there was no mistaking we were at elevation.

Steve

 

The general rule of thumb is 4% loss of power for each 1,000' elevation gain. At 6,000' elevation that equates to 24% power loss. Welcome to my world. I live at that elevation.

The rule may only apply to normally aspirated engines, not forced induction.

I pull my 11k (GVWR) toy hauler up 11,000' mountain passes with my 6.7L. It does well, but it's working hard with engine oil temp of 243 and transmission temp of 232. That's a mountain pass. If you're not hitting the passes then you should be OK, but you might be wishing for 4.10 gears.

 

That's interesting. I think we were usually running in 4th and downshifting to 3rd with our 6.2, but our transmission temperature never went up. Normally with that load we are in 5th and downshifting to 4th. But we also dropped down to 3rd sometimes which seldom happens to us on the flat.

 

the truck computer will take care of the engine.. just fine. fuel injection is so NICE.

fyi.. higher up you should see 85 in stead of 87.. use 85...

Yes, 20 to 25 percent loss is possible... and Normal
yes,1 gear lower and held longer. maybe 2 gears.....

long ago... semi-tractor-trailer Gas engines with 200 hp did them mountains...
just more work by the driver

 

Agreed. My prior truck got the best MPG on 85.

 

This video should give you good info

 

You are correct, Jim. A turbo-charger compensates for the lower atmospheric pressures at higher elevations. In the Rockies and Sierras, when my truck is working hard it's because of the grade(s), but I don't notice a decrease in performance due to the elevation. The same was true when I flew private aircraft. A normally aspirated piston engine would loose power as we climbed; a turbocharged engine would keep on cranking out the horses.

Rob

 

Thank you for the confirmation Rob.

 

superchargers and turbochargers..

during and after world war II...... fighter planes, race planes.

 

If you are going to stay on I-90 you will be in South Dakota and Montana not Nebraska unless you use I-80 and then cut up to 90.

I home base out of Nebraska at 2000 ft and run the mountains of Colorado often pulling my trailer and with the new computer controller motors the altitude affect is less notacible than when we had carbarators, its really has changed. My first EFI was 91 460 and it was better than my old 460 with a carb after I installed a Banks Power Pack, my 2000 V10 was a hands down improvement over the 460 and my 13 6.2 is amazing how it compensates for altitude. With 4.30 gears I really don't notice much of a change until I hit the 6K point with a real drop off around 8 to 9K, the way it adjust is surprising. The route you are planning will be no problem as far as altitude goes but you may be running into some head and side winds but just go down a gear and you won't have a problem, just remember the whole time you are heading west you are going uphill but when you head back east you will be going down with the prevailing winds behind you. I always figure my mileage going both ways not tank to tank.

Denny

 

Yep. I pulled a 8,500 5er up through the Eisenhower Tunnel with my Ecoboost and it seemed totally unfazed by the altitude.

Replacing the Ecoboost with a F250 6.2 with 4.30s soon. I'm a little concerned that the 6.2 is not going to pull as strong as the Ecoboost; especially at altitude. But, I need the additional payload; and don't want a diesel.

 

I have pulled my 8,500 lb fiver up through the Eisenhower Tunnel with my 2015 F250 with the 6.2 and 4.30s and it held between 55 and 60 all the way up. The truck definitely knows that the camper is there, and there were a few downshifts into 2nd gear, but it gets the job done.

 

Thanks for that info. I will have to get used to the additional RPM.