Quote:
Originally Posted by uncleal13
Well thanks all for your input.
I took possession of my new 06 Century 450 Mercedes, 18 D/O, 3.58, 11R22.5 on 11 August. Have 9,500 miles on it so far.
Took 46,000 Edmonton to Palm Springs = 5.76 US mpg
15,000 Los Angleles to Cornwall, On = 7.45
5,000 Gatineu, QC to Edmonton, AB = 7.32
36,000 Edmonton to Amarillo, TX = 5.96
It's a bit of a dog on the hills, but with the tall gearing I was expecting that. Especially compared to my last truck with the 565hp ISX & 4.10 rears.
Since when is 3:58 tall gears? I've got 3:42, and with 35,000 LBs in the box, from WI to CT, averaged 7.16 mph. With 45,000 in the box, I average about 6.5 mpg. Looking at your mpg, I think I'll stick to my N-14. If I have to down shift, it's generally only 1 gear and keep on climbing.
Rocky... I have a problem with your theory of keeping it above the torque range. When climbing a hill, and keeping the engine above 2,100, what happens when the engine starts to drop rpm? You're going to get well into the torque range before you can really downshift. I know a few of the "hills" in your area. With a good load on, you're going to drop 2 and even 3 gears before you get to the top. Do you let it drop to 2,000, then shift down and let it turn at 2,400?????? Or do you drop the speed in "steps"??? I know my mechanic says I can let it crank up to 3,500, but with this type of engine, I NEVER have it cranking over 2,000. NEVER!!!!