XJ vs tj question

Jmccracken88

Active Member
Joined
Mar 28, 2016
Location
Thomasville
so I have a 01 XJ, very clean, little rust underneath... 126k miles, 3" lift, 31" tires, 4x4. Highway I get 20-21mpg. City, 16-17.

Why does the tj get worse mpg? I'm looking to sell mine and get a 99 TJ, and everywhere I look, people with comie at lift/tires get highway what I'm getting in the city.. But why? I was going to do a 2.5" and 31's
 
Aerodynamics and weight would be my guess.
 
Yeah, I know the TJ weighs more, but 400lbs shouldnt warrant a 4-5, or even 6 mpg loss... Theyre both bricks, both weigh close to the same and a stock TJ getting 4-5 mpg less than a 3" lifted on 31 XJ? Im confused
 
I'm betting none of the speedometers are correct, so nobody knows how many miles they're actually going per gallon used.

The speedometer is Cyd's jeep is off by something like 20%.
 
-TJ/YJs have windshields that are almost straight up compared to XJs they are some descent angle with flatter roof line. (aerodynamics as mentioned)
-gear ratio as mentioned
-the final drive ratio of the XJ AW4 vs the TJ auto(not sure what it uses) vs a 5spd too
-type of tires used, wheels, even type of lift, tire pressure, upgrades/mods. As a jeep guru, Cherokees for most part even lifted ride pretty stable compared to every customers TJ/YJ I've ever driven stock or lifted seem to just be all over the place so I'm sure that has something to do with it too (I would think).
keep the XJ!!:rockon:
 
marty79 said:
As a jeep guru, Cherokees for most part even lifted ride pretty stable compared to every customers TJ/YJ I've ever driven stock or lifted seem to just be all over the place so I'm sure that has something to do with it too (I would think).
Click to expand...

Wheelbase has everything to do with stability. Wheelbase to track ratio is a fundamental concept of stability in vehicle dynamics.
 
benXJ said:
Wheelbase has nothing to do with MPG, so has nothing to do with the convo.
Click to expand...

:rolleyes:

I was responding to someone (not about MPG), but if you're going to play that card:

Wheelbase is generally related to vehicle length, and vehicle length has a lot of bearing on aerodynamics, and aerodynamics are a large driver of MPG.

Rethink your statement?
 
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Jmccracken88 said:
Does a TJ not share the same AUTO trans as the XJ? And I assumed the gearing was the same as well.
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no on the trans. XJ uses AW4 from 87-01 automatics and couple different 5spds. TJ I'm not sure with but don't believe they use the same one (someone might chime in if so, I'm XJ guru not TJ lol but mess with them here and there).
Gears are "Most" common 3:55 on XJ Auto, 3:07 on Manuals. The 3:73 and 4:10 are there but pretty rare to find (4cyl 5spd more common on 4:10). TJ gears......sorry couldn't tell you.
 
Fabrik8 said:
:rolleyes:

I was responding to someone (not about MPG), but if you're going to play that card:

Wheelbase is generally related to vehicle length, and vehicle length has a lot of bearing on aerodynamics, and aerodynamics are a large driver of MPG.

Rethink your statement?
Click to expand...
Na, don't need to rethink. The original question was about MPG. Nothing else. You were continuing to drag the topic off course, which is a plague on forums. Wheelbase has VERY little, if any, appreciable affect on MPG. If anything, shorter vehicles usually are smaller/lighter, so they should get BETTER mpg, which obviously doesn't hold true with the wrangler, mainly due to its shape.
 
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