[Orangetxguy]

Originally Posted by marylandkw

What year is your C-15? Mine is a 06' turned up too 550 and I found my best mileage at 1250-1450 tops. At 1500 I can almost see the needle drop.

Mine is an 01, with 120K on the overhaul, set at 435 on the throttle 450 on the cruise. Tried running it at 1250 to 1450 like International suggested and averaged 4.8 to 5.2 mpg.

Cat suggested running the engine at 1450 to 1600...keeping the temp up to 190-200 degrees. The fan clutch is set to engage at 205! My mpg is running at 5.8 to 6.4...again depending on the terrain..and the load. If I am experiencing a lot of slosh in the tank I'm pulling...it knocks down my mpg...go figure.

I have always run the cruise whenever possible, on any truck I drive.

[solo379]

Originally Posted by mike3fan

if I run the 1350 that some say gives best fuel milage I am doing 67

Do you have a tall rubber? Cause my old truck, with the same setup, was doing 67mph at 1400 rpm. 24.5LP.
The "sweet spot" for Acert is 1325, i wish i specs my with 3.36! :sad: With 3.55, i do best, running between 60-62, sometimes it's fine, but sometimes, i need it a bit faster!
BTW "Sweet spot" does not mean best fuel mileage. It's only means that anything above it, may be unnecessary, and the waste of fuel.

[bigtimba]

. . "I would like to make a couple of observations about driving at this speed,I got really frustrated at other drivers and the way they pass slower trucks.I was pulling a flammable load and that made no difference to other drivers,they would tailgate within feet and what was really hard to take was how close they would pull back in front of you especially if it took them a little longer to get pass,you can guess the kinda carriers that it would take a little longer to pass someone going 62mph."

Congratulations! You're now an honorary Swift driver!

Seriously, now . . I'm driving an '05 Volvo, 361k, with a big red thing under the hood that says Cummins. I inherited this truck a couple of months ago showing overall fuel average of 6.7 and have managed to bring it up to 7.2. Cruise and pedal are cut at 63 and I cruise almost exclusively.

[Darin Younce]

Hwy Mike3fan, That would be around a 7 ct per mile savings or near 12% from what I figure. That is impressive! Imagine if every one did this . BTW, what speeds did you run before this?

[mike3fan]

Originally Posted by solo379

BTW "Sweet spot" does not mean best fuel mileage. It's only means that anything above it, may be unnecessary, and the waste of fuel.

Ok that makes sense,I do have 24.5lp

[mike3fan]

Originally Posted by Darin Younce

Hwy Mike3fan, That would be around a 7 ct per mile savings or near 12% from what I figure. That is impressive! Imagine if every one did this . BTW, what speeds did you run before this?

Yeah I figured it at .59cpm for fuel at that speed,I was always 5-7mph over the speed limit,with a top speed of 70-72mph

[marylandkw]

Originally Posted by sidman82

FYI, mine is a C-15 500hp with 3.73's with 13 speed. I do try and keep it at or under 1500 rpm's. Which is around 65 mph. I do go over that now and then, but try not to. Lately I've been going a little slower as I stated. It is a little easier for me as I stay local. If I was running the road I would probably keep it at 1450 rpm's @ about 64. I get 7 mpg.
I just did my IFTA and over the 1st Quarter I show 7.06 mpg.

Same specs aside from the HP and I never go over 1500 unless jake breaking. As the temp around here warms up I too see an increase in my at the pump mpg.

[solo379]

1 mpg difference, at $4.00 per gallon, and 120,000 miles a year, is about 15 grand difference in your pocket.....or out of your pocket :wink:

[Orangetxguy]

Originally Posted by solo379

1 mpg difference, at $4.00 per gallon, and 120,000 miles a year, is about 15 grand difference in your pocket.....or out of your pocket :wink:

Last week Dispatch wanted me to deadhead back to Beaumont from Laurel MS. I did the math, using 6 mpg (378 miles= 63 gallons fuel x $3.989=$251.31 in fuel) and .365 cpm drivers wages (378 x.365 = $137.97 lost wages) plus road taxes unpaid...sent them a message telling them the total estimated cost to deadhead for me was going to be $389.28....and asked if they were willing to work for free, if they expected me too. 15 minutes later I had 2 loads offered up. One that went to Lakeland FL..where I didn't lose anything..and the other to Bishop TX. Still a 230 mile deadhead back to the house...but the load paid enough without the fsc to make up the difference.

[GrayBeard]

I have an 02 INT 9900I. The truck has 3.73 rears, 10 Spd (0.74 final gear), C15 set at 500 HP, 1650 torque and tall rubber. This past week, I left Nitro for Lakeland, FL. Dead headed to Jacksonville (tank wash) and then to Savannah to pick up a load going to Craigsville, WV. Ran consistently at 65 MPH and averaged a stellar 6.74 MPH. I was at or slightly over 79K both ways. Flat terrain and 70-80 degree weather helped a lot.

I have run the truck this way since I started back at the end of Jan. 6.74 is the best I have seen to date. The worst was around 4.9 from Nitro to Avenel and back to Friendly loaded both ways. Was runnning at 65 to 75 MPH both ways.