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4.7L Gas Mileage Tracking

10K views 9 replies 5 participants last post by  01Motorsport 
#1 ·
Over the summer, I did a lot of statistics and data analysis at work, which got me thinking about keeping track of my gas mileage as I'm curious what impacts various conditions and modifications have on the 4.7L in terms of gas mileage.

Is this something that might be of interst to anyone? So far, for major events I have the Jeep TCM mod, superchips tuner, and other minor events (weather conditions, CEL, etc.).

I was thinking of posting the results in one of the TCM posts, but figured I'm planning on doing a bunch of things (intake, exhaust, gearing, etc.) that it might warrant its own thread.
 
#2 ·
Good idea, and thanks for being willing to help others out… but to anyone other then yourself, it would only be a single data point to use and not a lot of help. So many things effect milage (altitude, outside temp, engine temp, tire pressure, tire style, various sensor conditions, etc and your driving style most of all) that if you say "I got 20MPG with X, Y & Z mods", it really doesn't tell anyone anything because there are too many unknown variables.
 
#3 ·
While I do agree with the fact they can't be used quantitatvely, they can be used qualitatively to see what impact mods and other things have on mileage. I never intended someone to look at my results and say, "Gee, if I do X mod, I'm going to get a 2mpg increase because this guy did!". I more intended someone to look at it and say, "This person did X mod and it affected their gas mileage (either positively or negatively)."

While there are a lot of factors that affect gas mileage, if most conditions are recorded and the driving style remains consistant, if there are definite trends that occur after a specific mod is done, than I'm sure this could be used quantitatively. For instance, we all know doing the Jeep TCM mod adds a second gear for better mileage on the freeway, however what impact does it have in mainly city driving (obviously the extra gearing doesn't help, but other factors associated with the mod do come into play).
 
#4 ·
I could point to two different events on my fuel log, and state that "x mod" improved my gas mileage.

Then again, I have modifications that few others here have, and as far as I know, nobody else posts here about fuel economy, who has a quad cab 4.7L Dakota and lives in northeast Ohio.

Unless the mod in question really affects fuel economy (for example, installing mod x caused your gas mileage to instantly go from 15 MPG to 18 MPG), I'd have to agree with petrock in that fuel economy would be affected by too many other variables beside the mod in question.
 
#5 ·
I keep a consistent track of the mpg on my Dakota, primarily because I drive it 29K miles annually. Even small changes in mpg affect the gas expenditure, for me at least. Driving habits are the #1 factor in mpg variation, and that includes too much engine idle time when stopped. My truck has 265K on it now, but still gets 18-19 in the winter, and 20 mpg in warmer months. I make an effort to run 100% gasoline, but those days are obviously numbered. Synthetic fluids help, as does tire pressure checks every 14 days. As for the mods, the "grand total" is a max 2 mpg gain over stock:
*Superchips 91 program/ 93 octane fuel
*Jeep HO cams
*Exhaust: 2 1/2" primaries/Magnaflow Y-pipe/3" hi-flow cat/Magnaflow 22"/2 1/2" duals
*Stock airbox w/3" alloy tubes to TB/K&N drop-in/Fernco 4" inlet
*"True" 68mm throttle body
*Clutch fan removed/10" pusher fan w/controller/180 stat
*2" chassis drop
Counting the Snugtop and work cargo, I'm usually carrying about 400 pounds on the bed.
 
#6 ·
Wow thats some damn nice gas mileage! I have an '02 4x4 Dakota with the 4.7L and my average for the past month has been ~12MPG with mostly city driving - but don't take that as me complaining. How is your driving style? For me, I drive my truck to enjoy it. I didn't buy a truck and a V8 to feather the gas pedal.

I actually noticed a decrease of almost 2MPG (average) doing the Jeep TCM mod, which I attribute to the fact that high torque conveter lockup. I did gain 1MPG back doing the 87 octane superchips.

As for my truck, I have A/T tires which I know will impact gas mileage, but I also have the 3.55 gears which I've always found to be a weak point. I plan to upgrade to 4.56.

One thing I was curious on though, would running the 92 octane performance mode superchips flash increase gas mileage or would it have no impact (providing I drive the same way I do now and don't enjoy the extra performance).
 
#7 ·
When the truck had the stock 3.55 rear, Superchips 93 performance tune, CAI, 2" drop in the rear I was able to consistanly run 22.5 on the highway and 18 in the city. Once I changed to the 4.56 gears I got 21.5 highway and 18 in the city. As it sets right now I get roughly 20 highway and 16 city but Im also driving 30mph in the city im in and never run OD while doing so.
 
#9 · (Edited)
Generally I drive it pretty aggressive. The city I just moved to has alot of traffic and alot of lights so it's more slow starts :( my mods to date are. 4.56 gears, 2800 edge converter, cai, ho cams, no clutch fan, p&p 68mm TB, stage3 vb, full custom 2.5" y-pipe into single 3" dumped, and fully SCT tuned. My afr is generally around 14.5-14.7 while cruising and 12.5-12.7 during WOT
 
#10 ·
I would describe my driving style as moderate. I still haul ass on an Interstate entrance ramp :jester: If I want to pass somebody they get passed :D Most of the time, I'm in sync with the truck, shifting around 2500 rpm. Keep in mind that my Dak is a regular cab 2wd, the lightest curb weight at 3759 pounds. A quad cab 4x4 weighs in around 4450. Finding the ideal octane for your truck is simply trial-and-error. My truck will run ok on half 93 and half 89, but I usually opt for 93 if the cost is only 20 cents/gal. more. The rule of thumb is if you don't hear pinging under load or uphill, you're ok. Fill the tank and start recording your mpg to build your own data.
 
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