So I installed my Airaid CAI and 18" Mufflex muffler and switched over to 89 octane. My first tank of 89 octane average at 15.1 MPG. Is the computer still getting used to the change in octane? I only notice better mileage when I'm on the highway, I swear my city MPG has dropped. I'll check a couple more tanks before I decide to switch back to 87 and see where that takes me.

 

Year: 09
Model: 1500 Reg Cab, 20" Rims,3.92 gears
Engine: 5.7L Hemi
Highway percent: 100
City Percent: 0
Location: Ft Sill,Ok
Octane: 87 (Regular Gas)
Hand or Computer calc: Computer (I'll figure out hand next tank)
Miles on truck: <5000
MPG: 19
Mods: None

I drove almost 1,000 miles to Ft Benning,Ga recently and came back last Saturday to Ft Sill,Ok.I averaged almost the same each way.While I was at Ft Benning,driving stop light to stop light on post,I averaged about 13 MPG.I could'nt wait to drive back to Sill,lol lol.

 

Year: 09
Model: 1500 Crew Cab Laramie, 4x4,3.92 gears
Engine: 5.7L Hemi
Highway percent: 60
City Percent: 40
Location: Stettler, Alberta
Octane: 89 (Mid Grade Gas)
Hand or Computer calc: Computer (I'll figure out hand on next tank)
Miles on truck: 1300
MPG: 18.1
Mods: Lopro truxedo teneau cover

 

Year: 09
Model: 1500 Crew Cab SLT TRX 3.55 gears
Engine: 5.7L Hemi
Highway percent: 98
City Percent: 2
Location: Tennessee, Ga, SC
Octane: 87
Hand or Computer calc: Computer
Miles on truck: 1800
MPG: 24.5
Mods: None... bone stock

Our return trip from Tennessee to SC netted me 24.5 mpg by hand calculations. This picture was taken before the end of the trip and had actually risen to 24.9 on the computer. After filling up the mileage came to 24.5 as well.

This was all Interstate driving, cruise set on 63 mph (MDS doesn't cut in much over 65, so I've heard). No A/C compressor running, windows up. Payload was myself, wife, child, and a weeks worth of luggage and some Christmas toys.

The mileage was continuing to climb, albeit slowly, even towards the end of our trip and I believe that it would have gone higher. Also, there was a good bit of mountains that we went through as well.

I got 20-22 mpg on the way up with the cruise set at 70 so the slower speed was definitely a contributing factor.

 

Year: 09
Model: 1500 Crew Cab SLT 3.55 gears
Engine: 5.7L Hemi
Highway percent: 50
City Percent: 50
Location: Western WI
Octane: 87
Hand or Computer calc: Both
Miles on truck: 15000
Mods: Step bars, tunneau cover, bed rails

I tested MPG the first time this weekend. It seems I have a nearly identical rig to the previous poster. 2WD must somehow make a HUGE difference as I baby the heck out of it trying to squeeze out every mpg. If I got 24 mpg I'd be doing cart wheels!!!!!!!

I believe 100% highway cruise at +-55 you can obtain 20MPG in my truck. I was at 19.6 when I hit the freeway. Once on the freeway cruise at 70 it dropped to about 18. I also realize that when it's cold it seems to take longer for the MDS to kick in. The system must pour the fuel in pretty heavy until all systems are to proper operating temp.

So tank one which was about 50% highway and 50% city I was 16.0 computer 15.6 by hand.

Tank two was 5% city, 60% highway, 35% freeway was 18.2 computer 17.8 hand.

So my puter is .4 mpg on the optimistic side

 

If you maintain low 60's mph you can attain 23-24 mpg without the A/C compressor on. I would imagine that the compressor would shave 2-3 mpg off that figure.

 

I just bought a 09 hemi slt 4x4 crewcab.... I have about 1k miles on it. My first 180 miles was a highway trip. I got MPG to 18.4 driving at 68MPH and it would drop down to 16.2 at 80MPH. I eventually quit farting around and locked i at my normal 78MPH and averaged 15.5 (not the 20+ most of liers out are claiming). Then trip back averaged 15. I make this trip twice per week. Each time My MPG has dropped. I drive 90%highway 10% city baby the hell out it, drive like a damn grandma and now I'm getting 13MPG. WTF! Truck has 1000miles and I went from 18 to 13. Same trip, same gas, same fricken tire pressure, only difference is weather is now 5-15 degrees colder in the last week. How can truck drop 5MPG like that for no reason? I'm about ready to get rid of dodge and go buy a ford!

 

Year: 09
Model: 1500 Crew Cab SLT
Engine: 4.7
Highway percent: 10
City Percent: 90
Location: Garrett , In
Octane: 87
Hand or Computer calc: Computer
Miles on truck: 1200
14.5 to 15.3

 

Hi Everyone, I purchased my Hemi in early September, I pulled a 4500lb camper right away with it..I found out a little later I shouldn't pull anything for the first 500 miles.....gas mileage was horrible when pulling, I made less taht 400 km per 120 ltrs of gas.
Now however, with no trailer I am able to make 800kms per tank full.

Year - 09
Model -1500 ST Quad Cab 4 x 4
Engine - 5.7
Gears...3:92s
Tires-17 and 20
Highway percent - 90
City percent - 10
Location -Montreal, Canada
Octane - 87
Hand or computer calc - hand
Miles on truck - 7000 kms
MPG - 18.83
Mods - none

If we calculate it summed up to 18.83 mpg.
You can correct me-=- if I can make 800kms on 1 tank, 26.4 gallons
800kms =497.1 miles
497.1 / 26.4 = 18.83 mpg

This almost all highway driving. At a cruise control of 65mph....
Thought it would be much better than this.....
Dario

 

I just finished a trip from Corpus Christi to Dallas and back and this is what it works out to: a little over a thousand highway and about 400 in and around Dallas and Fort Worth

Year - 09
Model -1500 SLT CC 4X2
Engine - 5.7
Gears...3:21
Tires-Factory 20s
Highway percent - 100 up and back
City percent - 50/50 mix while there
Location - Corpus Christi/Dallas
Octane - 87
Hand or computer calc - Both
Miles on truck - 1900
MPG - Hwy- 20.1 Cruise Control on, as steady as traffic allowed
Comb- 17.2 a combination of neighborhoods, shopping,
short highway areas
Mods - none

There was about a 2/10 of a mile difference between my math ???, and the computer.

I do not normally keep track this way, just buy how much it has cost me and that dropped by 25 dollars this trip.

My GMC with the 6.0 and 3.55 rear got 16 on the highway on a good day.