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So with ga$ prices creeping up over $4/gal, I decided to try a little experiment in my Commander. I was averaging 12.9 mpg with 65% highway driving. I drive around 80 mph on the highway and around 10 mph over on the secondary roads.

My experiment was to see how much I could increase my mpg by keeping the RPMs at or under 2000 RPM. Before I post my increase, I will describe what it was like:

- It was difficult to accelerate with such slowness but I did "kinda" got used to it. Traffic would sometimes accelerate faster than me, but not by much.
- On the highway, 2000 RPM = ~68 mph (GPS calculated). This was the more difficult thing to do since I was driving around 12 mph slower than I normally do on the highway.

After running two full tanks like this, I was averaging 15.9 mpg... a 23% increase.

Final Thoughts: Although difficult to change my driving habits, saving $17 on each fill up is worth it for now.

I want to know if anyone else has done something like this or has any other techniques that might help.

John
 

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That's a substantial increase but I don't think I could retrain myself to do it. I guess it's worth a try though.
 

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Since your hiway mix is so high I'll wager that you would retain 15mpg+ if you drove in town as normal but kept to the 68mph highway speed. May go up if you go ahead and drop to 65 on the highway. Speed kills our highway mpg, that's for sure.
 

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I've noticed that keeping the RPMS BELOW 2k gives a significant increase in MPG. I shoot for 1700-1800.
 

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Also don't forget that cruise control is your friend, if it's safe to use. (I have a hard time with it in heavy traffic.) I've noticed an easy 1+ MPG increase on large vehicles like a Suburban by using cruise as opposed to using the gas pedal.
That computer is much more precise than my right foot.
 

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I have recently set the cruise on 66MPH (It is actually more like 72 with the oversized tires) And I can get about 16-17 on the highway. If I crank it up to 70 (76) It kills the MPG down to about 14.
I also noted the EVIC is optimistic in its calculations even though with the larger tires it souldn't be..
 

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I have a 2006, 4.7, QDII, Class IV Tow. I don't know your axel ratios. I purchased new and just went over 16,000. I live in Ft. Wayne and drive to Indianapolis. 2000 rpm = 73 mph. Going south against the wind I average 18.5. Coming home (North) with the wind I get 20.5. I always use Marathon mid grade. I went to northern Michigan two weeks ago, mushroom hunting. Again at 73 mph I got 20.5 and where 131 goes down to 60 north of Cadillac, it went up to 22.5 at 63 mph. I do not know if using mid grade helps, but around town, stop and go I always get 13.5 - 14.
 

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I know the EVIC doesnt know about my tire size so it should be giving me a much lower MPG than I'm actually getting. Bigger tires mean the engine has to work harder to turn the larger tires (higher gear ratio). Since the EVIC still thinks they're the same size, so the same number of revolutions per mile it should think it using more gas per mile. I think it is saying lower MPG than it did with stock tires but it still is higher than when I calculate it.
Oh, and tire size options in star scan don't go any larger than stock.... no where close to my size...
 

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Ya, this has already been discussed in this thread:

http://www.jeepcommander.com/forums/showthread.php?t=4588

Slowing down = good, not just for gas, but for safety, and also your nerves.

We even talked about 2000 RPMs in that thread. That is typically the max I will push it, even while accelerating.

I get ~17 MPG in city, and ~21 MPG on highway. Gas mileage is less about your vehicle's restrictions, and more about driver's mindset.

I don't know how these dudes in the F350s and massive trucks go about paying for gas with the way they gun it off the line and fly past people, lol...
 

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RedCommander said:
Depends on the person I guess. I'm a total wreck if I try to drive 65 or slower. I get very agitated driving under the speed limit. Even if I know it's the best thing to do.
..........X2
 

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Ya, because you're like most impatient folks on the road. ;) It's a race!

You don't have to go 65 or under the speed limit. I go typically 2-5 miles *over* the speed limit, but that's *slow* compared to everyone else around me. Most folks go 10-15 miles over, everywhere I go. The speed limit is 30, people are goin 40-45. Speed limit is 65 -- people are goin 75-80. Most folks treat the speed limit as a *minimum* limit, rather than a maximum speed limit, lol.
 

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I've been "slowing" down for the last 6 months or so...in all my cars. I've found the "sweet spot" for my Hemi to be in the 1800 RPM range. Equates to 63 - 65 mph. It took me about a month of "forcing" myself to slow down...now it is natural and I sometimes wonder what I was in such a hurry to do all these years. Can get 21+ straight highway, but, usually the mix is in the 17.5 - 18.5 ballpark, actual calculation, not the EVIC.

I just park myself in the right lane with the trucks, and some of them are running 55 - 60 to squeeze some more out of their $4.70 / gal diesel and enjoy the ride, and I mean enjoy. I am sometimes amazed at a lot of the stuff along a route that I've been driving for 16 years that I've never noticed before. Can't remember the last time I got my "blood pressure up" since I've slowed down - I don't think I ever thought about what the "road rage" was doing to me, always thought of it as affecting the other guy. I guess I've just reached that "age" where I've suddenly realized that there is absolutely nothing in the world that is going to be so dependent on me that it can't wait. This old planet got to 1952 without me, and it'll keep going after I'm gone. I'll enjoy the ride, much more so, in the Commander and by slowing down, I can enjoy it for 60 to 80 miles further per tank ;)
 

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I've tried this before too, but I reset the MPG and Trip A-B milages first, then started with highway driving first, and saw an increase in Gas milage. The Commander will adjust to your driving, "something I learned from the forum", when you reset the MPG and Trips, you'll notice a big change in acceleration once you come to your first stop and take-off, but it's worth it until you see a Hummer or TJ pass you and you decide to push it.
 

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with taller tires my rev's have dropped. i usually go the speed limit. its less stressful for me. i don't have to get as pissed when someone is going 50.
 

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Once I started going the speed limit, or under, I stopped worrying about a lot of things - cops for instance. I used to have the radar detector and was constantly on the look out for the odd car in the medium or on the overpass. Now, we just cruise down the highway, listening to the radio and getting to our destination a few minutes later.
 

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Don't forget that the mixture of 10% ethanol reduces MPG. So in places where they do not mix ethanol with gas, MPG's should be higher...at 60mph and with ethanol, I could squeeze 18 mpg hiway on a hemi.
 

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Discussion Starter #20
Is there a quick way to tell which pumps are cutting their gas with ethanol (certain brands, etc?)
 
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