ChilliXJ

Now im not to conplain about gas or prices other wise I would drive a Prius and wheel that..
I cant seem to work out but..
My WJ 4.7 gets 17 MPG on a combined cycle.
My XJ 4.0 gets 14 MPG on a combined cycle.
The XJ has had new NGK O2 sensors, walker cat converter, new 4 hole bosch fuel injectors, coolant and temp sensor, TB complete clean, new TPS and IAC, coolant flush out with new tstat and WP, frequent oil changes and new Chapion spark plugs.
WtF??? I thought the XJ should use less gas than the 4.7?

Bustedback

The WJ has MPG friendly gearing and more precise fuel management. Plus it slips through the air a little better than the box shaped XJ.

ChilliXJ

Ok so its normal then? 14Mpg is good for a well tuned XJ around town? On the freeway I can do 20 easy

Slim357

I got 24mpgs in town in my XJ on a 2" lift and 30" a/ts. Mine is an 89 tho. Figure newer models should do better but may e its due to my driving style that helped get the mps so high.

MUKAK

24 in town? u sure bout that?

ChilliXJ

You obviously dont have the 4.0? Diesel?

andrewmp6

The 4.7 was a brand new engine for the wj and designed more for power and mpg.And the wj is more rounded so drag on the body is probably less then the xj which is a box on wheels.

Kingfisher

Maybe you should re calculate.

andrewmp6

Only way i see any xj getting 24 mpg in town is diesel or being towed by something.

salad

Lol 24 MPG city with a 4.0L. Maybe if you run 2:1 gears and it's a bodyless frame.


Mister OP, indeed the V8 Grands have always had better in-town fuel economy than the 4.0L. It's not your imagination. It takes a lot less effort for the more powerful engine to get these things going. 4.0L WJ is pretty bad on gas. 2.5L in XJs is much less than you'd think too.

Slim357

I ran 8 tanks of gas and that was my average. I added a cai moved the ait and upgraded the injectors. Now with 35s im getting 10-14ish in the city.

thatXJguy

I wouldn't say that, exactly...

http://www.fueleconomy.gov/feg/bymod...Cherokee.shtml

ChilliXJ

My wife has just told me I should drop a V8 in the XJ. Dropping the 5.2 or 5.9 is more complicated than a 350 Chev / tranny combo?. There are threads on these, Ill start searchin.

ChilliXJ

I have calulated mine by a calculator, not by the EVIC overhead. Combined 80% in city with gridlock, occasional rev (flowmaster on V8... cant help it) I am getting 15.8 MPG. On the highway out country I get 20 easily.

salad

Well it's probably easier to get an OE finish since you stay within the same family (CCD bus I think).. no idea on fit I've seen these swaps before and they're pretty slick.