Best Ever MPG

[pontzdav]

Best ever fuel economy towing my FC30 with Silverado 1500 Max Tow Pkg, 6.2L engine at 66 mph westbound in Texas on I-40 west of Amarillo. Averaged 15.9 mpg. For an hour or so. Nice Tailwind. Usually average 12.9.

[sb55]

Originally Posted by pontzdav

Best ever fuel economy towing my FC30 with Silverado 1500 Max Tow Pkg, 6.2L engine at 66 mph westbound in Texas on I-40 west of Amarillo. Averaged 15.9 mpg. For an hour or so. Nice Tailwind. Usually average 12.9.

Attachment 379862

I have the same truck and Airstream. I’ve gotten up to 13.8 on a tank, but usually average about 12.6.

[dznf0g]

Originally Posted by sb55

I have the same truck and Airstream. I’ve gotten up to 13.8 on a tank, but usually average about 12.6. Attachment 379863

Roughly the same with same truck and 30' Classic. Have seen mid 14s...usually 12.4 average @ 65mph.

[jaybauman]

You guys are encroaching on the fuel performance of my Duramax!!! How dare you!!!

Long-term average (if I exclude Colorado mountain passes) has been in the range of 13.8 to 14.3 for my GMC 3500HD + FC30. All-time best is 15.6mpg on the very last trip we made before selling her.

[Duramax3oh]

Best I've captured was 19.5 MPG on the 25 mile trip odometer towing '21 International 23CB. Cruise control was set at 60 MPH during that period, flat land TX-LA trip.

Edited to add: Made the 350 mile trip from Houston to New Orleans on a single tank of gas. Total average MPG for the drive was 16.5

Signed,
3.0L Duramax

[RivetED]

2015 6.6L Duramax, 2500 Z71, 100% stock, no 'chip', no special diesel fuel, no DEF delete, & no Airstream!:

This was an extremely unique trip, when towing the 25' FC high 12's to low 14's are pretty typical.

[AstroBruce]

Do you guys really believe what the EVIC is telling you? Mine routinely tells me I'm getting 99 mpg when I take my foot off the pedal. When I do the math with a fuel receipt, I average about 13.5 mpg at 65 mph.

Bruce

[Duramax3oh]

Originally Posted by AstroBruce

Do you guys really believe what the EVIC is telling you? Mine routinely tells me I'm getting 99 mpg when I take my foot off the pedal. When I do the math with a fuel receipt, I average about 13.5 mpg at 65 mph.

Bruce

Nice extrapolation there.

I believe it’s a good baseline and estimate. I do not take much stock in (any) short term data point but believe it starts narrowing down on the accurate figure as more miles are driven. We’re talking average not instantaneous.

For the record there has been only one time that my hand calculated mpg after fill up has been less than what the electronic readout displays. The other 20+ times I’ve chosen to hand calculate my mpg it has been better than what the computer displays.

[dznf0g]

You can always switch the gauge to the 400 mile range. Gives you a pretty good estimate after several 400 mile stints.