CobraMarty

Synthetic oil- engine, trans, transfer case, differentials.
55MPH highway cruise! 65MPH uses 12% more fuel, 75MPH uses 25% more fuel.
Use your cruise control.

VTJeep

All in all this is an interesting thread. Your getting redonculous mpg's my friend! What about pulling the a/c compressor out and putting free spinning pulley on. Same for power steering if your feeling strong, I suppose..

-Remove carpet and various interior panels.
-Replace glass with lighter plastic (plexi maybe?)
-For every 100 degrees you can remove from intake temp you gain 10 percent of horsepower back, so wrapping everything in heat tape would help
-also, look into a cowle style intake. People on here have done them with great success. As opposed to the WAI you mentioned.

I used to drive a Subaru wagon (~2009) with the 2.5L fail. It had the screen with several options of info you could cycle thru. 2 of the features were realtime fuel economy as well as average mpg's. With it in realtime mode I would start seeing what type of driving habits would do what to the mpg's. Coasting doownhill in N resulted in ~65mpg over a constant ~2.5 mile decline. The realtime showed 99.9mpg when in N and a more accurate ~70mpg's in D. I also found that I was far heavier on the throttle than I needed to be to cover flat ground. The Subaru liked ~40mph the best. So if in a 35 or a 45 I'd find myself doing 40... Cruise control works well when on constant roads like interstates. Highways here offer too much hill and turn elements to utilize it as an economy feature, most of the time. Very gentle acceleration AND breaking helps. You can let off the gas far more often and sooner than you'd think. Also, if going up a hill, you don't have to maintain speed, sometimes you can afford to drop a few mph's up the hill and then worry about accelerating on the flat after. You know, work with gravity.

BobF

That's what I meant, thanks for clearing it up. Are we agreed that going into to neutral downhill does not improve anything regardless of AT or manual?

hankthetank

...

nv6r

Before I added a winch bumper, winch, and AT tires, I would consistently get 27mpg from my '96 XJ. I have seen a best of 30.16mpg. This was with 1.5" of lift, an AX-15 with the gears changed from 3.07:1 to 3.55:1, Neon injectors, and Michelin 235/75R15 LTX MS2 tires. Now, with 3.5" of lift, winch bumper, winch, the front of the fenders cut off, and 235/75R15 Hercules Terra-Trac ATs, I never see anything better than 23mpg and normally only get 19-20mpg on the highway. I am going to add an air dam for the front and roof (I do actually use my roof rack) and see if this brings back some of my MPGs.

captainofiron

agreed, unless you turn off the engine, which some hypermilers do.

VTJeep

Got 20.3 today. That's maxin it out for me though..

ziegler.1289

Not trying to argue but it seems unrealistic to be getting over 25mpg. Especially not 30mpg. The Jeep Cherokee 4x4 stock gets a highway of 19-20 according to its specs. I am curious what you have done to it that is letting you get 6 more miles per gallon, and shooting for more? A good air filter helps but its under 1 extra mile per gallon gain. But if there is something I am unaware of please fill me in cause I would like to get that mpg.

GreyDog

That's cool that you get so much. I don't have a good idea exactly what mine are but I'll check it out next time I put in gas.

I googled hypermiling.... does anyone remember the South Park episode where Kyle's dad gets a hybrid? That's what the person who wrote the article comes off like... Pretentious dick who looks down on people who don't drive high mpg vehicles while at the same time encouraging people to be unsafe, break the law, and **** over other drivers.

I drive very conservatively, rarely does my tach read over 2000rpms, I NEVER gas it to a red light, drive the speed limit (except on 70mph highways, I don't usually go over 65 period). Some of those hypermiling tips are just ridiculous and dangerous though.

nv6r

My XJ, when it was slightly modded -- but with stock trim -- would AVERAGE 25mpg; and see peaks of slightly over 30mpg.

mfohner

Have you considered not doing any of these modifications and telling your buddy you are getting the 30mpgs anyway. It won't be the first time he has been lied to, he bought a afford didn't he? What is the point of having the XJ if you are going to strip it down to nothing? Just a thought. I get 72 mpgs !!!

XJ Stryker

I call BS to this thread.

With those number u would be getting about 450 miles to a tank.

Reminds me of what mw paw used to say about going to school.

Let me guess you drive downhill both ways. Lol

Devodale

Just got back from a 1000 mile round trip around Northern Ca. Lets see..... 989.8 miles on 45.644 gallons of gas came out to.......drum roll please....... 21.68 miles to the gallon. I was going close to 80mph coming home on I5. Not bad for a stock as a rock 99' XJ with 257+K and a 'thumping' rear end. Even did some 4X4ing at midtrip! I'm pretty happy with that myself.

nv6r

I am sorry, but it is quite possible to get better than 25mpg out of an XJ with a 4.0l. I have had two of them that would. My current XJ is a 96 with Neon injectors, full-length header (the header made a big difference), AX-15, 3.55:1 gears (this also helped the MPG quite a bit from the 3.07:1 gears), and 235/75R15s. Before I did the lift, more aggressive 235/75R15s, winch bumper, and winch, I would get better than 25mpg, and got a best of 30.16mpg. This was using a GPS to confirm mileage; my speedometer is now right on the money. I am going to be putting an air dam on the front and an air foil on the roof to try to get some of the mileage back.

Gary Briggs

If the reported mileage is accurate, its pretty remarkable. I'm running ford 710 injectors which did help my fuel economy quite a bit, but I've personally never gotten anywhere near these numbers! The best I have personally ever achieved was just shy of 20, basically the only tank where I spent the majority of the time on the freeway.

I'm skeptical, I personally dont by it. The XJ does not have much going for it as it pertains to fuel economy, its not aerodynamic, its kinda heavy, it has a reatively large motor compared to economy vehicles.

Also hypermiling seems pretty silly to me, thats a pretty extreme way to save a few bucks!