Been looking at getting a 3/4 ton Suburban with an 8.1L for towing with. Unfortunately, I am a little bit leary of just "how bad" the gas mileage will be. A friend of mine has a Duramax and gets pretty good mileage, but GM doesn't put the Dmax in Suburbans yet Also, if you have some experience with the 8.1L, are you using the 3.73 or 4.1 rear end?
I worked with a guy who had a cc lb truck with that engine and he sold it to get a diesel because the milage was so bad. I think like 6-8 mpg around town but he has a heavy foot. I think in a burb 10mpg city is possible, but again this isnt 1st hand experiance. -Brent
My neighbor has a 2001 Chevy 3500 4x4 with the 8.1 and in town its 9mpg unloaded 12mpg on the freeway unloaded and pulling 10,000lb bumper pull he says the best was 11mpg on the interstate. The thing pulls like a freight train!
And unfortunately, they never will. I would take 3.73's. The slightly higher ratio would promote a little better mileage on the highway and the power of the engine would be plenty to pull most loads you would find behind a Suburban.
Thanks for the feed back guys.... I have also been reading some other information that the 8.1L used to (still does?) have an oil consumption problem. Anyone else heard of this?
I've got an '03 Suburban 2500 4x4 w/33s. We get 10mpg in town, 13.5 unloaded hwy (this is all sea level, 80 mph). Predator programmer boosted mpg @1.5. And yes, it pulls like crazy! It's hard to believe an aerodynamic brick will move like this thing does! Just bought an f-250 diesel for better mileage, but it's not nearly as fast in stock form. Mine burns a quart of oil every 2500-3000 miles.
I have a 2001 Silverado 3500 with 8.1L and a allison trans with 4.10 gears.It gets 11.5 empty and 8 loaded.And yes they pull like crazy. I would like to learn more about that predator programmer that gained 1.5mpg.
I've still got it, sold the suburb. Could make you a deal...but if I remember correctly, it won't work because mine didn't have the allison.
