At the risk of getting flamed, I'll give you this as we're all amongst friends here.
I totally agree with you. It goes against everything I've done in my other rigs as well. My old Honda commuter liked it under 2500 and I could pull over 40mpg in that car. Both of my old '80 4x4 K10 Chev short box liked it around 2200 rpms and my current '78 4x4 K20 long box with 350/400/203 and 35's like it around 2200 as well.
My '07 Subaru 4 cyl boxer is finicky and does best around 2800-3000 but spins around 3500 in 5th at 70mph. No matter what I do to this car, the BEST I can ever get out of it is 28mpg, and 26mpg is average. If I don't clean the TB on that car and keep it tuned like I do my Jeep, it will only see around 22mpg.
I have TWO main daily drivers-my '07 Subaru that I used to commute to work in, that since my baby girl was born my wife now drives all the time, and my '05 LJ Rubi. I commute about 50 minutes to work from the new place and with what I do with my Jeep, mileage IS important to me. Being a poor college student years ago driving a built 4x4 Chev, I did what I could to get the most out of my $20 gas budget-which didn't go far in that truck! :laugh: Because of that, I don't put up with the crap about "it's a Jeep, get used to it". Yeah, it is a Jeep, yeah, it is a Subaru, yeah, it was a full size Chev truck, yeah it was a Honda, but who gives a rats ass-you CAN make them perform to the best of what they'll do with a few simple tricks and regular maintenance. When you're broke, you find ways to stretch the dollar and the difference between 10 mpg in a Jeep and 17 average is HUGE. I'll gladly take a few extra steps to get it up there.
That said, when I was on stock gears and 33" rubber, my rig HATED life. I HATED life. Besides losing 6th all together pretty much everywhere and using 1st as a dedicated starter, and horrible off-road performance, my gas mileage tanked to about 11mpg if memory serves. I couldn't tow my trailer either so life was awful for a while-piss poor performance, piss poor economy, piss poor off-road use. The Jeep was crippled. A simple gear swap to 4.88's brought things way back to being good again in all aspects, and YES, I did gain mileage back. I forget exactly how much, but it was around 3mpg or better.
Now, on your other thoughts, you are correct on a couple things-keep tires aired up and your foot out of it for the most part. That's the funny thing about factory gears that everybody thinks is so great for mileage-it took way more fuel to get up and moving from a stop light with factory gears and 33's than it ever will with deeper gears. You loose a HUGE amount of fuel with your foot in it at a stop light and getting up to cruising speeds than you ever will maintaining cruising speeds with the factory gearing. Factory gearing with taller rubber also draws more fuel to maintain those speeds as the engine is lugging a bit to maintain. At higher rpms up in the "power band" if you will, the engine is operating at peak efficiency making it's most power. Horsepower/torque and mileage go hand in hand as do intake,exhaust,vacuum, air/fuel, etc., etc., etc. You can't rob peter to pay paul and come out even in the end-something has to give somewhere along the way. Faster speeds draws more fuel to get the power it takes to maintain said speed in any given equation up until the engine is running at peak efficiency. At that point with everything in tune you'll realize the most power, best performance and most mileage. Getting there is the trick.
I know every Jeep is different and this does go against everything you'd be lead to believe in other vehicles, but keep in mind this is a Jeep with a 4.0L engine, not a big V8. They say there's no replacement for displacement as which with comes in a larger engine. We have the i-6 and it WON'T perform like a big V8 no matter what you do to it. My rig is heavy in comparison to the old Honda, and heavy still when compared to the Chev trucks that DO have a v8. We won't even bother to comapare it with my '07 F350 superduty flatbed diesel... I know where my rig runs best and that's where I keep it for highway use. Off-road is totally out of the equation and should never be considered or thought of. I don't, and won't ever calculate mileage or expect to get good mileage when wheeling. You shouldn't either-I'm talking strictly highway miles here for a DD rig. That said, 3000 rpms is where MINE wants to be. I'm not an engine builder nor do I understand exactly what is happening in the engine or why, I just know it works.
So with your "power band" and short shifting-I NEVER short shift. My rig spools up quick with the 4.88's, higher flow exhaust and mustang airbox. I run it up to 3000 MINIMUM to shift and often over that upwards of 3500 or so so that when I make the shift to the next gear, it's already IN the power band it needs to be and not lugging to get there. Not sure how to explain it other than do a short shift from 1st to 2nd at 2000 and note how it pulls in 2nd. It will be more noticeable in the higher range so try it again between 3rd and 4th shifting at 2000rpms at a rolling speed of say 20mph. Next time shift it IN it's power range of 3000 or better and note the difference in performance when you drop into 3rd or 4th in the higher rpm range-it will get up and move much quicker than it ever would at 2000. Make sense? Try passing a semi on the highway up hill in 6th gear at 60mph and see how long it takes you to pass said truck. Do the same dropping to 5th, or even 4th if need be, rev it up at or over 3500 before shifting and see how much quicker you can pass said truck. The engine is in it's optimum efficiency range for lack of better terms where performance is best, and consequently mileage will be best too. Now, don't get me wrong, you won't get the best mileage passing semi's uphill at highway speeds, but point being-if you drive your rig on the street lugging all the time, you're essentially doing the same thing... Another example if you have a new style Ford/Chev/Dodge truck to tow with-tow a trailer in "TOW/HAUL" mode and note where the auto transmission shifts and at what range. Same thing in the Jeep.
Please keep in mind this is MY observations driving MY rig. Nobody knows my rig better than I do and I don't expect anybody to drive my Jeep and get the same performance I do with it. Take my wife for instance-she is very in tune with the Jeep and can point things out to me that are wrong that I don't notice. She's often right. BUT the difference between my driving and hers is the equivalent to nearly a 5mpg difference. With her driving-no matter what shape my rig is in, she won't ever get better than about 12mpg, maybe 13 at best. All in driving style. She shifts early and keeps the rpms low no matter what I tell her to do. I can't teach anybody how to drive their rig for best performance. I do know what works best for ME in MY rig with all the testing and playing I've done over the years and some of that is listed above. Please keep in mind this is not the end-all be-all answer to getting the most out of your rig-this is just what works for me. I've played with it a lot over the years and yes, it does go against everything you've been lead to believe... As to something that will blow your mind-on our recent trip to the Rubicon Trail, I had a couple tanks over 18mpg and two tanks over 19mpg. This was over a 2000 mile trip and MANY tanks of fuel. On that same trip, I had a horrible head wind with driving rain and had one tank at around or just under 15mpg. Like I said, LOTS of variables... Your results may vary.
Enough rambling, I gotta go hack up the Jeep to build some new parts...
edit-I should also note I run "regular" fuel which I think is 87 octane here. The above is for highway driving-city for me is always lower too due to stop/go driving.
Best of Luck,
Mike
