I just recently put a 3 inch lift on my XJ with 31x10.5 and my gas milage dropped significantly (never really had that good of milage). what can i do to help save some money at the pump?

 

Your mileage should not suffer that bad with 31 inch tires. What do estimate your MPG to be now? I am getting 16 MPG with the stock drivetrain and 33s.

 

Honda Civic FTW!!

LOL jk. you can get like 1 MPG for every 2 things you do to increase air flow.

A bored throttle body, coldish air intake, free flowing muffler, high flow cat and headers.

Really the only way to get more power from a 4.0L is forced induction...

 

Would adding a snorkel equate to being a cold air intake?

 

It would be getting cold air, making it a cold air intake.... but from what I hear, snorkels are quite restrictive, and can hurt the flow of your intake. It is usually recommended to disconnect the snorkel until needed and then reconnect for normal driving.

To the OP. There are a lot of things you can do. Free flowing exhaust, cat, headers... a real cold air intake, proper gear ratios, bored throttle bodies, and shave as much weight as possible (heavy bumpers, winches, keep the trunk empty, ect.)

All in all, the XJ is not a very fuel efficient machine to begin with. If you are looking for more than 20-22... buy a honda.

Good Luck,
Jeep450r

 

just a quick question... did you recalibrate the speedo for the larger tires? that would throw off your calculations a little.

 

Also run the tires at their max pressure

 

x2
with bigger tires you are going a longer distance per revolution, but it is still registering as one revolution from your stock tire size. With 31's you could add about 12-15 miles per 100 miles you go to your tank. This should give you a more accurate reading until you can re-calibrate your speedometer. Also, your streets mpg will suffer a lot, but your highway mpg will be somewhat better, so if you drive streets a lot more than highways, then your not getting a good average.

 

yeah this is the big question cause i have 33 with stock gearing and when the heep speedo says 65 i am going close to 80 like 78 or so and that makes a big difference when trying to figure mileage. if your tire size is off by 15 percent then the reading will be off that much to and so will the mileage on the jeep. just something to think about

 

If you have the stock air filter box in there check to make sure that the baffle at the opening is out. it restricts flow a bit and that would help. keep your air cleaner clean or buy a new one. Change all the fluids in your drive train to lessen the friction. re adjust your rear brakes a little to lessen the drag. Do that with extreme caution though. Too much loosening will make the rear brakes less effective and could cause a failure of your front pads and control in an emergency situation.

Reduce whatever wieght you have on the xj and whatever areodynamically challenged add ons you may have. I know that jeeps are the worse aerodynamically but safari racks add alot of drag.

Keep the jeep tuned and run some b12 chemtool or techron through the fuel system to help clean up the injectors. When the fuel atomizes well and mixes with the air it burns more efficiently.

the rest is common, Upgrades to exhaust to allow free movement and lower back pressure a bit.

last thing that really effects milage is driving style. lighter on the pedal is better on the wallet. You didnt state if you put on wider tires. The wider the tire the more friction with the ground and more energy needed to get them rolling and keep them rolling...

 

A K&N air cleaner set up is a good start, easy to do as well. The stock air box is very restrictive.

 

Here's good tire size calculator: http://www.miata.net/garage/tirecalc.html

 

My Cherokee with everything stock seems to get 22MPG combined. when i had the lift on i was getting 18MPG and everything is stock, no cold air intakes or anything just stuff that was on it when i bought it. BTW if you want a car that is good on gas mileage and can still have fun in the dirt you don't get a HONDA, you get a Subaru impreza, forester or outback, a honda's only good for everyday road drivers and street racing... i also agree that you should make sure your tires are filled to max, also check fluids, air filters and spark plugs.