Alright, I'll just start with this disclaimer: I don't support or recomend any special products and I did attempt to control as many variables as much as possible to make this venture even noteworthy. I don't do EOC (mostly because my AT doesn't seem to like it, and the Jeep handles pretty spooky without power steering) though I do neutral coasting (NC). I am pretty good at timing lights and try to manage to never completely stop rolling (unless a traffic cop is around) even in moderate city traffic. Long story short, still adjusting the nut behind the wheel and the scangauge is helping immensely.
So here's the big story, I returned from Iraq about three weeks ago, and have proceeded to slowly perform some needed maintanence on the only vehicle at my disposal, the 2000 Jeep Cherokee. (March 20) I thought I had a dragging brake caliper, and I changed the entire front brake system out and flushed it completely through at the same time. Not normally where one would start "ecomodding" but I figured a detrement was the first place to start so as to have a reasonable starting point, that, and I could only figure that was the reason for my abysmal highway milleage (around 18 mpg). This is a figurative number, but is probably all I have to work with as I only tracked tank mpg before (pre ecomodder days for me) and drove 95% highway. Next (April 2) I tackled changing the differential gear oil in both the front and rear with some high end synthetic as well as changing the tranny filter and adding 4 quarts of new synthetic to it (I'm keeping to the manufacturer recomended viscosities, just going synthetic should help keep the colder weather here from making the oil "extra thick" and make less work for the drivetrain).
Since I've been back, I have made the same 92 mile trip five times to relatives of mine that live on the Olympic Peninsula in western Washington. To get there, I have to cross two bridges and continuously change elevation throughout 50% of the trip, but not enough in more than three places (when traffic permits) to make NC worth it to keep enough speed down a hill as to not pay a huge penalty going up the next. I know better than to try and accelerate up hills, as my 4.0 will go to about 10-12 mpg in a heartbeat uphill if I'm not monitoring the right foot. So far I've found that keeping the throttle steady at around 18-20% lets it stay steady on small to medium hills, and slowly decelerate about 5-10 mph on steeper ones, but still keeping mpg between 19-20 on uphills. I've established that my Jeep has some definate "sweet spots" for good FE: from 49 to 52mph (note: it shifts into overdrive at 43mph at around 1450 rpm) and anywhere between 60 and 68 if held steady gives about 22-26 mpg solid depending on traffic and road conditions, but back to the main point. On the three trips of the five I have been able to use the scangauge on (notably, all with the same approximate weather: raining steadily about half of the trip, 45-50 degrees F, and all trips between 5 and 8 pm) here are the overall trip MPGs:
Trip 3: 21.2mpg (after brake job) (March 28)
Trip 4: 23.3mpg (after diff and tranny oil change) (April 3)
Trip 5: 23.2mpg (April 4)
These are the best numbers I've ever seen out of this rig, with flat roads I'm sure it could get even higher. I will mention that I didn't partake in any "drafting" persay, as anytime I was above 55, there wasn't anyone within 3-4 carlengths of my front bumper.
Back to my disclaimer: I don't endorse anything, but I do advocate good maintanence. And I don't claim any of this to be truly scientific, but they are results and I like anything in the positive. For now I'm just happy to get that extra 5mpg as that's 25% or better than my previous mileage, whether it's from proper maintance, adjusting the nut or both!
Long story short, I've probably gone as far as I can without aeromods, but I have in the plans a removable overt-the-bumper and grillguard shroud (block incoming air from going in, but allowing the radiator to "suck" air through the grill as needed") with undertray that extends back to the front differential to smooth airflow from the front and some type of camback or removable boattail for the rear. Though I won't be able to even compete with the more economical cars on this site, I still want to get it as close as I can and still maintain it's "offroadability"
Sorry for the long post, but thats enough ranting from me, my upcoming work schedule is murder and my funds are tight the rest of this month. Also being as it's rained everyday this month, it's not a good time to do cardboard mockups when I lack the benefit of a garage. When I do get to it (probably at the start of next month) I'll be sure to make a build thread. I want this thing after mods to have a trip mpg of 30 (that would make it head and shoulders better than my wife's Kia Sedona minivan at 24 mpg solid
) which would give me a better than 500 mile per tank range.