Fuel Mileage

[Traps90]

Was just curious what you folks we're getting for fuel milage with the Cummins 8.9 and 40-42' coaches.
Lets say on relatively flat terrain and pulling your towed.

Thanks Trap

[akadeadeye]

Quote:

Originally Posted by Traps90 Was just curious what you folks we're getting for fuel milage with the Cummins 8.9 and 40-42' coaches. Lets say on relatively flat terrain and pulling your towed. Thanks Trap

Cummins 400 ISL we get 6.8 to 8, mostly 7.2 when towing with no headwind. We get 7.5 when not towing and no headwind. Speed matters, as does wind direction and grade. We drive 60-62 mph when towing and no more than 65 when we are not towing. Drives my DW nuts.

Don

[gmanatl]

I have a 2008 Winnebago Tour with ISL 400 and consistently get 9.2 while pulling our grand cherokee at 63 mph.

[wardy]

My 2007 Allegro Bus w/400 ISL gets from 6.8 (mountains) to 8.7 MPG, on average I get get about 8, not bad considering. I try to keep about 5 MPH below the left lane prevailing traffic. Ideally I'll keep the tach between 1600 & 1800 which will give me over 8 MPG.

[Traps90]

Thanks for the replies guys, since I've never even driven a big motorhome it's nice to have an idea.

Sounds like the fuel milage is about 10 percent worse than what I get with my Ford Diesel pulling a 36' 5'er

Trap

[kjburns]

The trip computer shows that we've averaged 8.1 mpg over the past year (6000 miles). We also tow a Grand Cherokee.

[Stogie]

Thought I was getting 7 to 8 but checked this last trip going from 3500 to 9000 ft elevation with a 20 - 30 headwind most of the way and got 8.4.
Color me happy.

[Wayne M]

I have a smaller engine, ISB 6.7, 340hp, 6 speed Allison 2500 with Airens(sp) controller. Most of the time I averaged 8.9 between fill-ups. I have had as much as 11 and as little as 7.2 (west coast mountains) Last time out I filled up in San Antonio, drove to Texas City, and when I parked it in the driveway it was 10.0. My best (11) was at a constant 55 mph (Yep! Drove DW mad - why are we going so slow????)

[Pusherman]

Quote:

Originally Posted by Wayne M I have a smaller engine, ISB 6.7, 340hp, 6 speed Allison 2500 with Airens(sp) controller. Most of the time I averaged 8.9 between fill-ups.......... and when I parked it in the driveway it was 10.0.

When I'm parked in my driveway, I get a million miles per gallon (Sorry Wayne, I couldn't resist...)

I know this is a thread about Cummins engines. Mine's a CAT C-7, and we averaged 8.4 mpg for 2010. Everything I read suggests the Cummins engines do a little better on mileage than the CAT C-7, but I do like the torque on the CAT.

[sam-tip]

I have a 2008 tour and get the about the same. 6.5 to 9 at 65 mph.

My question is how many miles do you have on your engines. I have 17,000 miles on mine. I think break in in about 25k. On my Dodge trucks with the cummins 5.9 and 6.7 engine I don't get great milage untill they get over 70k miles.

Doug and Marcy

[powerboatr]

our ISC 8.3 improves with engine speed
if i keep it at 1800 - 1900 ish rpm i can manage a good 8-9 at 67 mph
if i drive 60 it seems to be not in the sweet spot and uses it pretty quick