My dad is using my 88 for a few days because his is down. he filled it up today and said it got 27 mpg! most was interstate, some regular highway running 65 mph. im very impressed! go go IDI! lol

that is with 3:55 gearing, 35" tires, 140,000 miles, 5 speed RCLB custom F-350.

 

Um.... 3 tank fillup minimum average before I will believe you. Its probably closer to 22-24 MPG, but it would still be impressive.

 

before this the average was close to 20 around town driving hard. BTW the speedo is dead accurate.

 

He probably didn't get it full. After a few more tanks, let us know...

 

I had a result that was in the low 30s once. Was very exited but decided to go around the block and doubled back to the cardlock to see if I could top it up more. I ended up cutting the MPGs in half just by correcting my error.

I know the 6.9 can deliver 25 MPG under the right conditions, but I still remain skeptical until I see more data.

My all time best single fillup was 24.9 MPG,

Best average that accounted for previeling winds, 22.5 MPG

And my real world average is 20-21 MPG highway and 15 MPG towing highway. City average is usually 13 MPG, but thats because they are all short trips with warm up time eating a big chunk of the potential.

 

well it took the same amount of fuel it always has for its given point on the fuel guage (at half tank it uses roughly 8 gallons, this was a hair above half tank). like i said i was getting 20 mpg with it after i turned up the pump one flat, added the ram intake and g code injectors. when im really hot roddin it'll drop to 17.

and my dad filled it to the brim, and i always do as well. i wouldnt say it was 27 but definatly 23/24.

 

drop to 17?

with my 6.9 turned up a flat and a c6 when i stomp on it im lucky to make it above 12

 

My F350 quad cab dually got 18.8 hwy on a 350 mile run

 

20 mpg again today and that was runnin 901 down to 183 (lots of hills) into Reading...not to bad i think!

when i drive i usually get 16 or 17 but i keep it on the govener

i love this truck, has plenty of power being N/A and in third (which seems to be the speed gear) i can get up to 75 bouncin off redline. i dont even know if i wanna turbo it...it runs so good.

 

This is a lot more like what I get from mine.

 

im thinking of turning it up a flat and a half more after i get my stacks and pyro in 8 mpg here i come!

 

my 89 F-350 crew cab duelly E40D consistantly gets 12.5

 

'93 dually gets 12.5 no matter what.