SO gas prices as you all know are going up, every guy I talk to that has a lifted xj gets alot better gas mileage then me what can I do to help this. Right now I have edge performance kit and the live wire upgrade for my plugs, I am working with a 6 in lift with 33 by 12.50. and I am getting 10.5 mpg all the guys I talk to are getting like 15 mpg and above.
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Gas Mileage
- Thread starter XJ_Muddin
- Start date
AZCA jeeper
NAXJA Forum User
- Location
- Phoenix, AZ
Did you re-gear it? If not, that is where your problem is. I think you need 4.88 gears for 33's, but I can't be positive.
Ba-Riedo
has frame envy
- Location
- redmond/bellingham, wa
4.56 works great with 33's.
-Alex
-Alex
Mudderoy
NAXJA Forum User
- Location
- Katy, Texas
1998 4.5" lift 32x10.5x15, 3.55 gears, same gas milage, about 210 miles per tank. I'm going to the 4.56 as soon as I can.
jwtrapper
NAXJA Forum User
- Location
- Wetmore, CO
You have to adjust for the tire size also. Get a GPS and go for a drive and check the differance. Or count mile markers.
Mudderoy
NAXJA Forum User
- Location
- Katy, Texas
If your adjusting for mpg, yes, if you want it to read correct on the speedometer get a new speedo gear. Less than $30 and very easy to install, especially on a lifted XJ. 15 minutes to swap.
fscrig75
NAXJA Forum User
- Location
- Burkburnett/Lawton
I'm getting ready to regear my rig, I did the equation in the FAQs, and per that I should go with 4.11. I haven't been able to find 4.11 for the 8.25 so I was going to go with 4.56. Is this still going to help? Or by going to to low is it going to hinder? THX
I'm and idiot, there are 4.11 but would the 4.56 help or hurt?
I'm and idiot, there are 4.11 but would the 4.56 help or hurt?
Last edited:
- Location
- Hammertown, USA
fscrig75 said:
There are 4.10's for the 8.25, which is the same thing.
What size tires? If you have 31's and are never going bigger, 4.10's will be fine. If you have 32's+ or plan on going bigger, go with 4.56.
Mudderoy
NAXJA Forum User
- Location
- Katy, Texas
They both have to be changed, and they both have to be the same. Same ratio, but the right ring and pinion for your differential.
If you haven't already done so get a build sheet for your XJ. You can request it via the Chrysler web site. The build sheet will tell you what your XJ had from the factory. There are other ways to tell but this is free and very good information to have.
The higher the ratio the more gas you'll save! If you can get into a negative ratio, the gas will actually "appear" in your tank!
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tiremike
NAXJA Forum User
- Location
- Springfield, MO
WITH OVERSIZED TIRES TRY RECALCULATING YOUR MILEAGE SINCE YOU ODOMETER IS READING SLOW
- Location
- Hammertown, USA
XJ_Muddin said:
If your question is that general, you want to save money and pay a professional to change your gears. Its not an amateurs job; in fact, its the one thing most of us "do EVERYTHING yourself" people pay someone else to do - myself included.
- Location
- Hammertown, USA
XJ_Muddin said:
You will need gears, a master install kit, and a carrier, for each axle (plus labor).
What rea raxle do you have? You may find it in your best interest to upgrade that BEFORE paying to have gears installed.
tiremike
NAXJA Forum User
- Location
- Springfield, MO
AT A SHOP $300 REAR AND $350 FRT IS ABOUT THE GOING RATE IN LABOR, WITH THE GEARS I WOULD RECOMMEND A REBUILT KIT MAYBE LOCKER SINCE IT DOESNT COST EXTRA TO INSTALL. IF YOU ARE LOOKING FOR A CHEAP DYI PROJECT FIND AN OLD 4CY 5 SP XJ WITH 4.10S AND JUST SWAP THE AXLES. I KNOW ITS NOT 4.56 BUT IT IS CHEAP AND A NICE SUNDAY PROJECT.
- Location
- Hammertown, USA
tiremike said:
Or an old 4 cyl auto with 4.56's.
Either way you end up with axles that have 20 year old bearings and a dana 35. Not the best route.
fscrig75
NAXJA Forum User
- Location
- Burkburnett/Lawton
muckleroy said:They both have to be changed, and they both have to be the same. Same ratio, but the right ring and pinion for your differential.
If you haven't already done so get a build sheet for your XJ. You can request it via the Chrysler web site. The build sheet will tell you what your XJ had from the factory. There are other ways to tell but this is free and very good information to have.
The higher the ratio the more gas you'll save! If you can get into a negative ratio, the gas will actually "appear" in your tank!
I tried the other week to get the build sheet via the website, got a nice email saying due to security reasons..... blah blah blah. easier just to go to the local dealer
I was going to go w/ 4.56 eventually I want to go up to 32s, I've got 31s now.
- Location
- Hammertown, USA
Do you know what axles you have now?
If you don't, snap a couple pictures and post them.
If you don't, snap a couple pictures and post them.
wild1joker
NAXJA Forum User
- Location
- fayettville,nc
3 weeks ago I changed to 4.56 gears. I also changed the speedo gear to compinsate .I am getting 17-18 mpg. I have 33-12.50's and 5 inch lift. the gears made a huge difference in torque and drivability. I highly recommend doing the gear change with 33's. also my friend works at a speedo calibration shop and my speedo is within 1-2 mph.
