Fuel MPG

[DeepVee]

1998 Detroit Series 60 with an Eaton 13-speed in a 41' twin screw rig pulling a 10K lb enclosed trailer. My average bounces between 7.63 & 7.65 MPG according to the Detroit computer and depending on the hills. We pull at 66 MPH at around 1450 RPM's. I'd love to have a taller gear but just not sure it's worth the effort & cost to change them.

[petrel]

Based on everything I've read, I should be consistently doing better than 7mph, instead of hovering between 5 and 7. Some research on the trucking forums has given me about 20 different things to check.

I'm going to begin with finding a Detroit Diesel service center I think I can trust and getting them to read the computer setup and make sure all the parameters are right. After that, a search for intake leaks will be next.

Interestingly, one of Detroit Diesel's troubleshooting guides mentions an overfilled crankcase as causing a reduction in economy. I have had the oil changed in the rig three times since I purchased it, by two different Freightliner dealers. Each time they have overfilled it between 1/4 and 1/2 inch over full.

[DeepVee]

I've been putting 9-gallons of oil in my Series 60 with two of the big Baldwin filters.

[petrel]

It looks like both dealers I used added 9.5 gallons.

[bushpilot]

Just scored 8.57 on 588 miles last night - we cruised a steady 75 and saw 80+ more than I'd care to admit.

Driving was mixed mountainous wytheville va to maridian ms

[bushpilot]

Originally Posted by bushpilot

Just scored 8.57 on 588 miles last night - we cruised a steady 75 and saw 80+ more than I'd care to admit.

Driving was mixed mountainous wytheville va to maridian ms

I should add that we haven't run the 10k gen at all.

[petrel]

That is some great economy. I don't think the gennys burn more than about a half a gallon per hour, so I would not discount those numbers.

[bushpilot]

meridian ms to Baytown (Buc-ees) Tx

493 miles, 53.3 gal = 9.26 mpg
And cheap @ $1.79 per gallon

[petrel]

Had a conversation with a nearby DD service center representative yesterday. Hopefully, sometime in the next few weeks I'll get the rig in for an ECM settings check and a spin on the Dyno. I think we are in agreement that either a setting is wrong or there is an intake air leak.

[bushpilot]

Id love to know why my fuel BURN seems is so uneven.....13 gallons difference per side.

[petrel]

The draw down on my tanks is never uniform. I think some of it is in the fill. One nozzle shutting off before the other or tank position (tilt). The balancing is never perfect, and the genset draws from just one side.

[bushpilot]

Originally Posted by petrel

The draw down on my tanks is never uniform. I think some of it is in the fill. One nozzle shutting off before the other or tank position (tilt). The balancing is never perfect, and the genset draws from just one side.

ok makes me feel better, thanks!

i have seen (when near bone dry), that i can have as much as a 20 gallon difference - where possible i try to fill one side at a time (even in a master / slave pump island) so that i can monitor the gallonage / consumption per side.

in the picture above you can see i only covered 500 miles (1/2 a tank on the dash/gauge) and was 13 gallons lower on the drivers side (where the float is).

[Bottomland4x4]

Just got back from a 1250 mile trip to Florida, pulling 21,000lbs I got a whopping 6.2 mpg! Had a terrible headwind down and back.

[Java230]

Man you guys are making me feel bad! My little F450 got 8.9 on my last trip.... Lots of passes and running 60-65 but still. I figured I would do better than you big trucks.

[bushpilot]

8.9 at 60/65 isnt anything to brag about....I get that at 72 with plenty of peaks to 78+
certainly headwinds will kill us all.

[Java230]

Originally Posted by bushpilot

8.9 at 60/65 isnt anything to brag about....I get that at 72 with plenty of peaks to 78+
certainly headwinds will kill us all.

Yeah thats what I was getting at, surprised your bigger trucks are doing so much better than mine.... I dont have a helpful rear end gear though. 4,88's are likely not helping. Im turning 2k rpms at 62

[Bottomland4x4]

Bush pilot, I wonder if the size of the bunk area has a lot to do with your mileage? Haulmark conversions usually have a smaller over bunk than the renegades, and I'm sure the aerodynamics have something to do with mileage. My toter was also an extended height which makes it less aerodynamic.

[Bottomland4x4]

My new to me, 2006 renegade 2800bm got 8.46 mpg coming from Nashville Tennessee to mt airy, nc. Not too bad for the hills. I found the gear ratio sticker near the fuse box and it is geared 3.21. This coach does have the egr. It feels more powerful than my old 16foot toter with a non egr Mercedes. This coach only has 26,000 miles so it's pretty new. We have our first trip planned for June 11th, headed to the beach. Last year my old renegade was showing 9.23mpg, so I will be anxious to see what the new coach does.

[samcrimm]

So Bottomland,

Did you buy the truck over in Hohenwald? If you did, I looked at his trucks and they were great, but I found a cheaper one in MS.

Sam

[Bottomland4x4]

No, I looked at his inventory on line and they were over my budget. I found mine on racing junk, it was only posted for 2 days when I found it. I feel like I of a really good deal. It was a one owner with only 26k miles, and was kept indoors. It only needed a really good cleaning and update the TV sets, it still had the original sony tube TV sets.