There is maybe a .5 mpg difference. Get the V8; more power for the heavy WJ's and hardly any difference in gas mileage.

 

My 02 is getting 19.6mpg 40/60 city/highway

 

I get about 21.4 on highway.

 

Yeah get the V8 in WJ. Those 4.7s are really nice.

 

Some people can squeeze a few extra mpg from the i6. The v8 will tend towards 18 in mostly highway driving in stock form.
There is practically no mileage difference with the part time case compared to the awd case. All the same junk is always causing rotational drag in the driveline with both systems.

 

Always enjoy reading mileage threads, but hvaen't seen any posted with the 24MPG as of yet. I guess it's early.
Although the EPA ratings are not etched in stone, at least they afford comparisons, so if Dad is concerned with fuel mileage, have him look at the EPA fuel mileage site. Only recommendation I can give is to make certain the Jeep is a '01 or newer as that has the 5 speed AT. It is said that teh '99/'00 can be reflashed to add the 5th gear, but have no experience at this.
As was stated in your other thread, the AWD (which is an on damand system, not AWD) system uses no more fuel than the 242.
Here's a couple of examples:

2002 Jeep Grand Cherokee 4WD
Jeep Grand Cherokee 4WD 6 cyl, 4 L, Automatic 4-spd, Regular 13 city 18 hwy
Jeep Grand Cherokee 4WD 8 cyl, 4.7 L, Automatic 5-spd, Regular 12 city 17 hwy

2004 Jeep Grand Cherokee 4WD
Jeep Grand Cherokee 4WD 6 cyl, 4 L, Automatic 4-spd, Regular 14 city 19 hwy
Jeep Grand Cherokee 4WD 8 cyl, 4.7 L, Automatic 5-spd, Regular 14 city 19 hwy

To sum it up, you'll find no difference in mileage with the QT/QD/242 systems in a particular model.

Don't know who will be paying for the Jeep, but I'd be more concerned with the cost of repairs then to the fuel mileage. You'll find that the WJ's, with mileage are money pits, and stay away from the AZC Limiteds/Overlands, unless you're willing to spend $1200 to fix the system, or you can do the work yourself. Look for a Laredo 4.7 with QTII and you'll be good to go, but you're still looking at window regulators, radiator, starter, HP PS hose, maybe already replaced, heated seats that are broken, and depending on the area of country, pay particular attention to oil pan rust and also under carriage rust. The pans are paper thin and won't hold up to much rust, so if bubbles have started a new pan will be in the future. Good luck.

 

I'll put it this way. My 2004 QuadCab Ram 1500 with the 4.7L averages 14MPG right now. My ZJ with the 4.0L averages about 14.5MPG right now. Enough said.

 

I drove a 2004 2WD 4.0 for about six months and the computer said it got 15mpg. I bought a 2002 Overland all time 4WD 4.7L H.O. about six months ago and the computer says 18mpg. Both of theese Jeeps are all stock, the 4.7 will get worse mileage if I race it around everywhere I go but it's well worth the extra power IMO. Try for a 4.7L H.O.

 

Don't go by the computer, do the calculations yourself.

As most have said, both get comparable MPGs. I don't have any first hand experience, but from what I've read on these forums it seems like the 4.0 and 4.7 get about the same. With that said, go with the 4.7 and you won't regret it :thumbsup:

 

When I looked, the 4.0 was rated at 19 highway, and the 4.7 was rated at 20 highway. Don't ask me how that works. :dunno: The plus you get with the 4.slow is its legendary reliability and it is...well...relatively easy to work on.

 

i have an overland i thought they had an extra overdrive gear. i can get 24mpg if i do 55. but 20-22 is more like normal highway driving while doing 65-70. over 70 though and it sucks fuel

 

I had a '98 dodge ram 5.9L got me like 12mpg a little more it was awful and $80 to fill. My I6 zj gets an 18.2 avg. If I really want to i'll buy another Honda and get 30-40mpg

 

If you are pretty easy on the 4.0 you can get decent fuel economy. For instance, about two weeks ago I drove down to Harrisonburg, VA (about 250 miles), and got about 22.5 mpg, which was a little less than I normally get with my ZJ on the highway since I was going faster than usual. On the way back I took it easy varying between 55 and 65mph on the highway, while drafting trucks the whole way. By the time I got off the highway, my VIC was reading 26.5mpg, and by the time I was done driving through towns and hitting hilly backroads to my house I was at 26.1mpg. My VIC is usually fairly accurate when I did measure it, however occasionally it has been a little high (.5mpg or so).

 

If you can get 26 MPG in a Jeep, write to the car manufacturers and tell them your secret.

 

WHAT NO ONE ELSE MENTIONED:

as soon as you do any type of tire upgrade, going to a larger diameter, the 4.0 will most likely get worse mileage, just because you have to give it way more gas to do the same work, where as the v8 has so much more torque, you wont really see a difference.. to a point

besides that i agree with everyone, they are just about the same mpg, I6 might do bearly better but not enough where i would get one, the v8 is sooooo worth it

I6 is a amazing engine dont get me wrong, perfect in a tj or xj but its underpowered in a z/wj

 

How many times do we have to have this discussion?

It's been proven time and time (and time and time) again that the fuel economy is the same.

V8s are great for the pavement. Power off the light, great on the highway.
I6s are great on the trail. They have a stronger, flatter torque curve, and can wheel with ANY V8, and better in many cases. And they still get you where you need to go on the pavement.

I own both. I love both. My I6 could not keep up with my V8 on the pavement. But the I6 will out-wheel the v8 in many crawling situations.
I've seen my (lifted)stock I6 crawl easily over things that (lifted)stock V8s have to rev up and run at.

 

How many times do we have to have this discussion?

It's been proven time and time (and time and time) again that the fuel economy is the same.

V8s are great for the pavement. Power off the light, great on the highway.
I6s are great on the trail. They have a stronger, flatter torque curve, and can wheel with ANY V8, and better in many cases. And they still get you where you need to go on the pavement.

I own both. I love both. My I6 could not keep up with my V8 on the pavement. But the I6 will out-wheel the v8 in many crawling situations.
I've seen my (lifted)stock I6 crawl easily over things that (lifted)stock V8s have to rev up and run at.

I agree, the straight 6 has an awesome torque curve. On the other hand, there's a reason serious hillclimbers run V8s w/NOS.

 

Kruzin has a point. The WJ version of the 4.0 has a pretty flat torque curve. The peak torque is 230 @ 3000rpm. It has 210+ available from about 1300 through 4400 rpm. It will idle over the tallest of curbs easily too.

 

my two previous cherokees (xj's) with the 4.0 did fine on mgp's in town and on the highway...i'm searching autotrader.com hard for a wj with a 4.0 ONLY b/c I don't want the aluminum 44a rear axle...if it is purely a street ride (which most are) the 4.7 should do fine, and comparable to the 4.0...i just want lockers w/o having to upgrade an axle....b/c i don't do rockcrawling but I do LOTS of trail riding...hunting season here in VA!
i also like the room available to work on the 4.0 w/o having to kill your knuckes in the process....

 

Mine is a 2004 with the inline 6 and 42RE. I usually get about 17 mixed for running around town and a few short highway trips, but I have been experimenting with hypermiling when I travel for work. On one stretch of curvy, twisty hwy in Miss I managed to go 50 miles on 2 gallons of gas (VIC and Fill-up confirmed). That is going 50 mph and creeping up the hills, but still... The I6 has the capacity to get pretty good mileage if you stay off the pedal. And from what I can surmise, it definitely has better servicability and reliability than the V8.

 

Thanks for all the replies, they are really helping me out. I am still leaning towards the v8 simply because I am going to be on the street almost exclusively and I would love that extra power if it doesnt cost me a whole lot in gas. What do you guys think about the reliability of the v8? I have heard it is just as solid as the I6 but i know its a little harder to work on without the underhood space like the I6 provides.

 

Your getting the V8. :laugh:

Trust me, ZJ 4.0 slow. WJ 4.0 cant imagine. 4.7 WJ probably a tick or two under on mileage but everyday you drive it you dont have to bang your head against the wall. 4.7 all the way.

 

Heres a good comparison.
My jeep- 01 xj weighs at least 375 pounds overstock. 31's on 3.55's, and 4 inches of lift.
4.0L- Gets about 14/18, cause of the bad 3.55 gears.

My dad's jeep-04 wj special edition -2 inch lift, 245 75 r 16's, sliders.
4.7L- With a heavy foot, still pulls 14/19.

We do convoy's all the time. Driving from the bay to humboldt county (300 miles), We consistently got the same mileage.

And the 4.7L is an awesome motor. The torque is silly.

 

Nice MPG, but the only real way to tell MPG is calculate by hand and a GPS

 

My 2000, 4.0 with a cold air with 101k manages 22mpg on the highway at about 55-60 mph. In the city it gets 13-17. That's because I play with turning Overdrive and I sometimes give it a heavy foot light to light.

 

Befumo - I've borrowed my mom's 99 WJ 4.0 plenty of times. It's a little weak on the highway (primarily in the hills) once you hit 70+, but it's just fine around town. Then again, it does have 3.73 gearing, which I'm sure helps some.

It's definitely no racecar, but around town it'll do as well as (or a bit better than) a V6 Camry for power. It certainly makes my little 140hp I4 Hyundai cry.

 

Befumo - I've borrowed my mom's 99 WJ 4.0 plenty of times. It's a little weak on the highway (primarily in the hills) once you hit 70+, but it's just fine around town. Then again, it does have 3.73 gearing, which I'm sure helps some.

It's definitely no racecar, but around town it'll do as well as (or a bit better than) a V6 Camry for power. It certainly makes my little 140hp I4 Hyundai cry.

Well i have the limited so its a little more wait, maybe we are even weight wise? 4.0 with 3.73 gears. Its slow from a dead start.. i have never really raced it. Its not as bad as people say once you start getting around 1.8-2k rpm its fine. But im not sure how much that damages gas mileage. My ZJ still needs a tune up, alignment, exhaust fixed.. so LOL who knows.

I think the 4.0 is fine on the hills highway wise, but for the ZJ i dont know if we have different trans but constantly i get stuck on hills on the backroads. You have to get a good head of steam or just take OD off.

 

I had a V8 WJ before the Inline 6 I have now and downgrading was a bad decision. There is almost no difference and I miss the power of the V8.

 

Go V-8.

As far as WJ's being money pits: 200k miles. So far I've put in about $1,200 in repairs including changing to a 242 TC.


They're NOT money pits unless you get a loaded one. If you have a "basic" Laredo (no dual climate control, no heated seats, no sun roof), there really isn't much to break.

 

Go V-8.

As far as WJ's being money pits: 200k miles. So far I've put in about $1,200 in repairs including changing to a 242 TC.

They're NOT money pits unless you get a loaded one. If you have a "basic" Laredo (no dual climate control, no heated seats, no sun roof), there really isn't much to break.

With the exception of the 42RE tranny behind the I6. But even those aren't too bad if maintained. That's the key. A ZJ or WJ will last forever if it's well taken care of, but will be a total money pit by 100k if abused.

 

i'm getting 21.2 highway, with 30 inch tires, no lift.

my 99 with the 4.0L got 22 at best stock.

city mileage is a little better with the I6, but not enough to get excited over.