Chevy/GMC 4x4 Van - Fuel Mileage

[Theshwed]

Hey All - I have been hunting for a new van for a while and am very close to pulling the trigger on a 2017 or newer GMC/Chevy Cargo Van to convert. I have not been able to find much information on real world fuel mileage for any 4x4 converted GM vans. Can anyone tell me your MPGs and typical range from a tank? I am looking at the 6.0 van. Are there any resources for auxiliary or larger capacity fuel tanks? I havent been able to dig up much information on those either. My '02 E350 has a 46 gallong transfer flow and it makes the driving range tolerable.

Thanks - Paul

 

[PNWExpress]

We have a 2014 3500 6.0 with a Quigley conversion with 140k miles on the clock. Cruising on the hwy under 70mph we average about 17mpg, streets 12-14mpg. We're pretty light footed.

 

[Theshwed]

Thanks. Does yours have the 3" lift, or is it stock height?

 

[marret]

Gear ratio will make a difference as well.

My 2008 with a 4" lift, 4.10 gears, 33" tires, 4 spd trans, bumper, gets 10-14 mpg.

 

[PNWExpress]

Thanks. Does yours have the 3" lift, or is it stock height?

It's taller than a stock Express. I've never measure to see how much.

 

[b. rock]

Also worth noting that 2010 and later should have an extra 2 gears in the transmission, so that'll have an impact. Boulder off road vans swears that their ones up on 37s still get 15mpg+ on the highway.