12 Valve Fuel Economy
Diesel Bomber
Joined: Mar 2010
Posts: 4,233
Likes: 434
From: Dansville NY
I have a 1997 Cummins 12v in a 1997 Ford F-350 4x4 with a 6 speed manual transmission. I went from getting 9-12 MPG with the 460 V-8 to getting 20-24 MPG with the 12v.
I pull a custom made 5th wheel (48' Long... 24' with bunks for a boat and 24' up front with a custom made Lance Camper to fit the style of the trailer). I can pull the fifth wheel fully loaded (about 10,000 pounds gross) 65-70 MPH and get about 19-20 MPG.
Before with the 460 I got 6 MPG and Could not even pull the dang thing.
Cummins All The Way!
Ford 460 =
Cummins 12v =
I pull a custom made 5th wheel (48' Long... 24' with bunks for a boat and 24' up front with a custom made Lance Camper to fit the style of the trailer). I can pull the fifth wheel fully loaded (about 10,000 pounds gross) 65-70 MPH and get about 19-20 MPG.
Before with the 460 I got 6 MPG and Could not even pull the dang thing.
Cummins All The Way!
Ford 460 =
Cummins 12v =
Diesel Bomber
Joined: Aug 2007
Posts: 1,525
Likes: 79
From: Livingston Montana
The best I got was 18 on 37s with 5 speed, 373s, and it tuned stock, I'd average around 14. I haven't checked it lately since I hardly drive it but I believe I'm getting around 12-14. Could be closer to 10 though.
Diesel Wrench
Joined: Jul 2009
Posts: 653
Likes: 56
From: Victoria BC
I have a 1997 Cummins 12v in a 1997 Ford F-350 4x4 with a 6 speed manual transmission. I went from getting 9-12 MPG with the 460 V-8 to getting 20-24 MPG with the 12v.
I pull a custom made 5th wheel (48' Long... 24' with bunks for a boat and 24' up front with a custom made Lance Camper to fit the style of the trailer). I can pull the fifth wheel fully loaded (about 10,000 pounds gross) 65-70 MPH and get about 19-20 MPG.
Before with the 460 I got 6 MPG and Could not even pull the dang thing.
Cummins All The Way!
Ford 460 =
Cummins 12v =
I pull a custom made 5th wheel (48' Long... 24' with bunks for a boat and 24' up front with a custom made Lance Camper to fit the style of the trailer). I can pull the fifth wheel fully loaded (about 10,000 pounds gross) 65-70 MPH and get about 19-20 MPG.
Before with the 460 I got 6 MPG and Could not even pull the dang thing.
Cummins All The Way!
Ford 460 =
Cummins 12v =
my old straight six gasser ford got about 16-17 avg, just finished my swap and filled up for the first time last weekend, when I go back home this weekend I'm gonna run that tank out and fill back up. I tried to be a little easier on this tank but its hard when its that much fun 
F150, 2wd, and 3.55 gears with 30 inch tires.... what do yall think I will get? got my fingers crossed!!
F150, 2wd, and 3.55 gears with 30 inch tires.... what do yall think I will get? got my fingers crossed!!
