Monocogger

Hi all, I've challenged my buddy at work and told him that I bet I could get a higher percentage improvement in my mpg's for fewer dollars than he could with his '91 ford ranger 2wd. I am driving a 4.0 '97 XJ 4X4 with 150k miles. I just aired up the stock size tires 1psi over sidewall max, folded in the passenger side mirror and took off my Thule roof rack. I went on a long roadtrip on country roads, hypermiling as best as I could and I ended up getting 25.6mpg. I'd really like to hit 30mpg but I'm not sure which direction to head next. I've heard that Neon injectors help a bit and they aren't too expensive. Also, I've heard that bored throttle bodies help too. I am already running a K&N panel filter, though, I'm not sure how much it helped for the cost. Other things I'm considering are:

• masking the grille
• underbelly pan
• ecu tuner (to adjust shift points and torque converter lockup)
• warm air intake
• '99+ intake manifold

I've done a lot of looking on this and other forums, but it's hard to quantify the mpg gains of each of these mods. Let me know what you think guys (aside from the fact that I'm crazy for trying to get "good" mpgs in an XJ. I'm already well aware of that)

wiggles

Wow that's impressive! You should replace the stock mechanical fan with an electric, they put drag on the engine. You could also take out any things inside that aren't absolutely necessary

askingxforxit

If you have AAA then take out your spare tire and tools. Maybe go with a skinnier tire with a highway tread, keep the rpms below 2000, take the rear bench seat out, and turn the engine off when stopped at a red light.

DieselD

Disconnect the front driveshaft? Might help.

I agree on eliminating to mechanical fan.

Didn't see upgraded injectors. There's a guy selling em on here for $45

Dan91

Can't believe no one's said it yet but be careful with your tires that full. It'll wear them unevenly and your braking/handling is likely decreased. Other than that, try doing what others have mentioned above, they all will help a bit. take out your spare tire too, I guess just try to cut weight wherever possible.

sportrider

have you tried drafting?

FlJeeper90

cut hole in bottom of truck and Flinstone it! lol Find long hills to go down and turn engine off. Jk, the electric fan is a really good idea.

4X4times4

Throw it in neutral going downhill.

wiggles

Oh and don't turn your ac on, it adds drag too
And if you have a crack in the exhaust manifold by the collector that will rob mpg's

OverlandZJ

WTH is hypermiling?

I'd be dancin the jig if i got 26mpg..

rob93

Google it a few of the techniques are a bit extreme for me.. but picking up more economical driving habits gained me a few mpgs in my dd

CobraMarty

Advance the timing 4-6 degrees with a crank position sensor mod.

weld3z

you well do it ..
1-clean the throttle here is fast and good way but his fault is he should clean it wile idle at 2500-3500 car must run .. 2-close A/C or Heater
3-spray your wheel bearings with some thing like WD40 or Break cleaner some time they are jammed and hard to move they must run free (I change them)
4-remove the spare tire ..
5-sea foam it ..
6-try to change you gas company fuel are different from company to other and yes i got around 30 miles more .. try it
7-fill your car slowly really slow and try to fill it in the morning ..
8-change the fuel filter ..
9-if you don't use the 4x4 remove the front deferential
10-wash the engine bay(i use this )
and under the jeep i use diesel then normal soap

i maximum got 375 mile with a tank, 2001 5speed all hight way no more than 70 miles 60-65 without cruise control don't have it in my sport

Good luck

87Warrior

I may be mistaken, but I don't think you will change anything about the transmission behavior with an ECU tune. The AW4 is independently controlled with the trans control module. You "may be able" to wire in a Renix era TCM and set it to the 'comfort' shift pattern. When the comfort/power switch went away, the TCM was defaulted to the 'power' setting. This would yield smoother shifts.

bajaxj

If this is possible it would be awesome! I like that feature on my 90 XJ.