Gas Milage improvment (3 Year Quest)
Thread Starter
Member
Joined: Sep 2013
Posts: 124
Likes: 5
From: Etowah, North Carolina
Year: 1999
Model: Cherokee
Engine: Stright 6
Gas Milage improvment (3 Year Quest)
Perhaps I am asking this question in the wrong form, if so please move it and forgive me.
I remember reading several months ago a thread about a guys three year quest to improve his gas mileage. I recall he did some simple and some not so simple things. Some simple were cover his fog light holes, restrict flow into the grill, even did something to his rear bumper to reduce air drag.
I am not 100% sure I found it on cherokeeforms.com but wanted to ask if anyone recalls this thread and can point me to it regardless of the form it is posted.
I remember reading several months ago a thread about a guys three year quest to improve his gas mileage. I recall he did some simple and some not so simple things. Some simple were cover his fog light holes, restrict flow into the grill, even did something to his rear bumper to reduce air drag.
I am not 100% sure I found it on cherokeeforms.com but wanted to ask if anyone recalls this thread and can point me to it regardless of the form it is posted.
Junior Member
Joined: Aug 2013
Posts: 102
Likes: 0
Model: Cherokee
Junior Member
Joined: May 2013
Posts: 45
Likes: 0
From: Athol, Idaho
Year: '86
Model: Cherokee
Engine: 2.5L
I too have the idea/dream/fantasy to improve the fuel economy on my XJ. Some of my ideas are kinda simple so I'll start with those ideas.
There are front locking hubs that can be bought and installed. Costs more than I paid for my Jeep.
The later models XJs (mine is an 86 with 2.5L I4) have MPI fuel injection (mine is TBI) have better HP. I'll have to swap the electronics with a late model - I'm in no hurry for that...
Mine is kind of a daily driver - no lift or monster tires yet (although I have a 3 inch waiting to be installed) big tires hurt economy so I'm going to go 30x9.5x15.
I hope this gives you some ideas... I'm sure there are others out that have done some of these steps and perhaps they will share too.
- replace the clutch fan with an electric fan - no need to spin the fan if you don't need it.
- replace the gear oil in both differentials and the transmission with synthetic gear oil - the transfer case gets synthetic auto transmission fluid - the synthetic is thinner for the same protection therefor less drag.
- add a MSD ignition box (work in progress) there are some youtube videos showing off MSD ignitions - if it makes mine idle smoother I'll be happy.
- Low restriction exhast - a glasspack or similiar low back pressure muffler.
There are front locking hubs that can be bought and installed. Costs more than I paid for my Jeep.
The later models XJs (mine is an 86 with 2.5L I4) have MPI fuel injection (mine is TBI) have better HP. I'll have to swap the electronics with a late model - I'm in no hurry for that...
Mine is kind of a daily driver - no lift or monster tires yet (although I have a 3 inch waiting to be installed) big tires hurt economy so I'm going to go 30x9.5x15.
I hope this gives you some ideas... I'm sure there are others out that have done some of these steps and perhaps they will share too.
Last edited by DanB.; Oct 13, 2013 at 10:26 PM. Reason: didn't read right...
CF Veteran
Joined: Oct 2011
Posts: 4,440
Likes: 3
From: Seal Beach, CA
Year: 1996
Model: Cherokee
Engine: 4.0 HO Straight Six
I too have the idea/dream/fantasy to improve the fuel economy on my XJ. Some of my ideas are kinda simple so I'll start with those ideas.[*]replace the clutch fan with an electric fan - no need to spin the fan if you don't need it.[*]replace the gear oil in both differentials and the transmission with synthetic gear oil - the transfer case gets synthetic auto transmission fluid - the synthetic is thinner for the same protection therefor less drag.[*]add a MSD ignition box (work in progress) there are some youtube videos showing off MSD ignitions - if it makes mine idle smoother I'll be happy.[*]Low restriction exhast - a glasspack or similiar low back pressure muffler. From here is gets expensive... There are front locking hubs that can be bought and installed. Costs more than I paid for my Jeep. The later models XJs (mine is an 86 with 2.5L I4) have MPI fuel injection (mine is TBI) have better HP. I'll have to swap the electronics with a late model - I'm in no hurry for that... Mine is kind of a daily driver - no lift or monster tires yet (although I have a 3 inch waiting to be installed) big tires hurt economy so I'm going to go 30x9.5x15. I hope this gives you some ideas... I'm sure there are others out that have done some of these steps and perhaps they will share too.
CF Veteran
Joined: Aug 2010
Posts: 1,678
Likes: 0
From: Carlisle, PA
Year: 2000
Model: Cherokee
Engine: Inline 6
an aerodynamic cherokee...its a box basically, gonna be tough 
its definitely interesting but a cherokee aint never gonna be that fuel efficient of a vehicle.
its definitely interesting but a cherokee aint never gonna be that fuel efficient of a vehicle.
Trending Topics
CF Veteran
Joined: Feb 2012
Posts: 2,282
Likes: 18
From: central IN
Year: 1997
Engine: 4.0
mine gets great mpg. it's all stock. fresh ignition components, ATF in the xfer case, syn 75-90 in the difs. 225 75 15 tires w 40 psi. I get 22+ mpg mostly under 50 mph, I rarely get on the interstate.
Thread Starter
Member
Joined: Sep 2013
Posts: 124
Likes: 5
From: Etowah, North Carolina
Year: 1999
Model: Cherokee
Engine: Stright 6
Yes this is what I was looking for, thank you.
I understand XJ's are not Honda Civics but I started to read this thread and then lost it.
I currently get 16.5/17.0 mpg around town light footed and 20.0 highway if I stay under 65.
I understand XJ's are not Honda Civics but I started to read this thread and then lost it.
I currently get 16.5/17.0 mpg around town light footed and 20.0 highway if I stay under 65.
CF Veteran
Joined: Oct 2011
Posts: 4,440
Likes: 3
From: Seal Beach, CA
Year: 1996
Model: Cherokee
Engine: 4.0 HO Straight Six
I doubt you'll ever get THAT much better than that
Junior Member
Joined: Aug 2013
Posts: 102
Likes: 0
Model: Cherokee
Since the XJ is as aerodynamic as a brick every single aero tweak does help get better gas mileage. For most of the guys here lifting their XJ's for offroading and getting better gas mileage is inversely proportional. For me since mine is a street jeep (bought it for the love of it's simple boxy look) adding a front air dam, taking of the roof rack, fixing the parachute of the front lights and rear bumper and driving conservatively (55 mph) will do the trick. I do agreee with the oil suggestions above.
CF Veteran
Joined: Oct 2009
Posts: 2,867
Likes: 16
From: Fauquier County, Virginia
Year: 1991
Model: Cherokee
Engine: I-6 4.0 HO
I just drive my Jeep and cry at the pump. Having fun with it later makes up for the crap mileage lol.
In reality, I cannot complain. When my Jeep is running tops and in good weather, I can get 20mpg on interstate going between 65-70mph. In its current condition... lol. My drums seem to be giving me problems and I am tired of them. They are def dragging and making my XJ drink fuel. Discs are almost ready to be swapped in.
(In all honesty, it's probably a shot e-brake cable as I have pulled and adjusted 3 times now. I just hate drums and used this as an excuse to get my wife on board with me buying disc brake parts lol.)
In reality, I cannot complain. When my Jeep is running tops and in good weather, I can get 20mpg on interstate going between 65-70mph. In its current condition... lol. My drums seem to be giving me problems and I am tired of them. They are def dragging and making my XJ drink fuel. Discs are almost ready to be swapped in.
(In all honesty, it's probably a shot e-brake cable as I have pulled and adjusted 3 times now. I just hate drums and used this as an excuse to get my wife on board with me buying disc brake parts lol.)
