2012 Mileage thus far SRW 3500 Crew Cab 4x4

[Beast2B]

"long trips at highway speeds' is a relative statement! My commute is 35 miles each way with 1200' elevation rise in the morning and back down the hill in the afternoon (300' at home, 1500' at work). I can get ~2mpg better roundtrip at 60mph versus 70mph, so speed needs to be taken into account when comparing mpg. A rural highway 55mph run will look amazing next to a 75mph freeway run of the same length. BTW, my oil change messages are repeating at approximately 4500 mile intervals with mostly empty commuting, but that may change since I got a VW TDI for commuting and the truck's miles will be more towing and less often.

 

[Cummins12V98]

A couple of posts here suggest the owner believes use of exhaust brake and fuel mileage are related. They are not.

Use of the exhaust brake has no effect whatsoever on fuel consumption. When the eb is open which is anytime the right pedal is pressed, its not doing anything. When the right foot is lifted, the exhaust brake closes and begins braking.

Tow/Haul mode has never been required for exhaust brake use, they are independent of each other, but in the Tow/Haul mode ecm/pcm programming is more aggressive and the transmission downshifts. The eb is used more aggressively in Tow/Haul mode.

Harvey,

I have to disagree, when the EB is on and TH and you let off it does not allow you to coast to a stop, with the EB on and TH off it does coast better. I have done multiple tests with my truck and you do get better mileage with TH and EB off. I run both on at all times. My testing is in town. Probably does not matter as much on the freeway.

 

[HBarlow]

Nonsense.

Please post the results of your "multiple tests. "

Would coasting and wearing out brake pads save you 0. 25mpg?

 

[RonD]

The Exhaust Brake is a brake, the Tow Haul in a simple term is automatic down shifts, so there are times when you don't want braking, and down shifts. I always drive with EB on, and when towing always have TH on, but there are times when you want to coast, example coming into Nevada decending on a long 3 % grade, the road is empty, and one can see 40 miles ahead, why have TH on, or the EB, it's nice to get a free ride for that section, but to drive without EB daily is foolish, your service brakes will cost more than the fuel savings by far

 

[AH64ID]

Would coasting and wearing out brake pads save you 0. 25mpg?

Coasting when you can, and using the EB when you need to slow faster than coasting is the best way to save fuel. I haven't done enough testing in my truck, but the little I have done I am able to coast at least a 1/2 mile longer. Do that 4 times in a 20 mile drive and you went 2 miles on the drive without using much (idle) or brake pads, that's going to manifest as a decent savings over time.

Coasting in idle is also better than coasting in gear. In gear you don't use fuel, but have some compression braking. In idle your just rolling. On my DD car I can get 40 mpg on my drive home coasting in N, and only about 32. 5 coasting in gear. That's all rural back roads where I can coast to a stop and the few stop signs I encounter.

 

[Cummins12V98]

Nonsense.

Please post the results of your "multiple tests. "

Would coasting and wearing out brake pads save you 0. 25mpg?

Nice Harvey,

I tell you what I have done and it makes sence. I never said how much better the mileage is but it is better. Drive the same stretch of road many times and reset the lie o meter. Have you ever tried it? My son is the one that suggested I give it a try because I asked how did he get better mileage than I did on the same route when he was using my truck. So I tried it and it is true by slowing down no TH and with EB on or off you will get better mileage than with both on.

I know it irks you if someone disagrees with you Harvey but maybe you shoulf try it before saying my results are NONSENSE.

 

[Ben S]

OK, 7340 miles now and 2nd oil change.

I have driven with the EB on since my last oil change and got almost 100 more miles on the oil before I had to change it this time. Don't know if the difference is real but I will post next oil change and see what it is. Very little change in driving habits between oil changes other than maybe one extra highway trip.

Drained the fuel filter and no water noted.

 

[Ben S]

Whoops... . that should say 1000 miles more on this oil change not 100 miles... . in another words i'm speculating that the EB helped extend my oil life. I'll keep running it until the next oil change and report back.

 

[Surefire89]

I just got back from driving up north, Haines - Anchorage Alaska. I was averaging 77mph with a 4000 ft elevation clime and decline over 1600 miles round trip. Had a light load (couple dirt bikes) but did well with my mileage consistently getting 21. 5. I ran my programer in "HOT" mode and had brand new 35x12. 5x18 Nitto Trail Grapplers on.

Gotta love diesel

 

[Surefire89]

"long trips at highway speeds' is a relative statement! My commute is 35 miles each way with 1200' elevation rise in the morning and back down the hill in the afternoon (300' at home, 1500' at work). I can get ~2mpg better roundtrip at 60mph versus 70mph, so speed needs to be taken into account when comparing mpg. A rural highway 55mph run will look amazing next to a 75mph freeway run of the same length. BTW, my oil change messages are repeating at approximately 4500 mile intervals with mostly empty commuting, but that may change since I got a VW TDI for commuting and the truck's miles will be more towing and less often.

You are very correct. Any object traveling at 75mph has 86% more drag than an object traveling at 55mph. This is partially why you will retain better fuel mileage going somewhat slower if you can control your rpms.