Cummin 12 valve Square Body Suburban MPG?

[Dieselwrencher]

Originally Posted by James Lamb

Ah. That makes sense then. I got 17 with a 6.5 turbo, and I always thought of the 6bt as more fuel efficient. But I don't typically drive as fast.

Thanks for the info.

Some 6bt's are more efficient than others. The VE rotary pump engines do really well. I had one I put in a 95 F350 crew cab long bed 4x4 that would get 22 highway and 18 pulling 18k no BS. I never should have sold that thing.

[Corts60]

The 80’s gm diesels were made to be fuel misers so they always get the best mpg. My 5.7 consistently got 22-23 mpg at 65/70. Any faster than that and it dropped down to 18/19. Just can’t pull anything serious. My buddies 6bt in a 4x4 dodge got 16mpg all day long. I used to drive a 7.3 for a short minute and it got 13-14mpg loaded or empty.

[v30crewcab]

I get 18-19 out of my crewcab on 35's.