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MPG decreaser

Stallacrew

NAXJA Forum User
Location
Cullman, Alabama
I suppose this goes here.

There is a thread of "Best MPG improvers"....but.....

What are the DON'TS of MPG's? I know that more weight means less MPG's and bigger tires ( generally) mean more gas consumption.

But what are ya'lls major add on's that kill the wallet on gas? Tire carrier? Roof rack? Gearing? Armor? and if so, how much did it kill MPG's?

I'm looking to do the tire carrier but will leave it alone if it kills my MPG's. I figure since it's in a little vortex back there it can't hurt much.

Biggest MPG killers and how bad?

--Alex
 
well i bought a jeep... thats a pretty big "DONT of MPG's" haha...but actually. we drive bricks. bricks tend to disagree with flowing air. if you want good mpg dont add on to the lack of aerodynamics...any extra weight or bulky things will lower your mpgs slightly so bumpers and roof racks dont help.. depending on how bulky your tire carrier is...it shouldnt be much of a difference..leave it on. better to have a spare and pay for the like $5 difference each month than get a flat and have to pay $300 to get it towed :p....really tho i know we are all wishing we had better mileage right now but its not even an issue worth bringing up...because its just not going to happen. lol
 
My tire is tucked inside the hatch, and when I say tucked, I mean that it's completely in the way.

My brick gets about 19 MPG but I think I could get more. I really wonder if a lift messes with the MPGs or if its just the tires that accompany it.
 
I have an 89 5 speed 2 door XJ that is completely stock other than a set of Michelin LTX 235/75/15 (the perfect size for an xj sans lift, IMO).
Running trips of 700 miles a day sometimes in My little Jeepy, I'll get 22 or 23 mpg. that's sitting at 80 or 85 mph for 8 or 9 hours. 3.07 gears have the motor turning just over 2500 rpms, and theres plenty of power left, and i couldn't be happier. I realize that mileage decreases most when we take a brick above 50 or at the most, 65mph. i don't have that kind of patience, but i am happy as a pup with 2 peters to be getting what i do out of it. 190k miles on the motor, a hoot to drive, and only gets stuck when i get stupider than the rig... it's all i can really ask. One day i'll blow through a tank at 65, just so i can brag about extreme mileage outside a 85 diesel.
someday.
 
Stallacrew said:
I really wonder if a lift messes with the MPGs or if its just the tires that accompany it.
In theory lifting the jeep exposes more frontal area (all the running gear is now exposed to the windstream causing more resistance). More resistance = less mpg. But wider and heavier tires along with compound variations can cause mpg drops.
 
swapping in a 2.8.
 
i was getting about 12mpg then i changed my plugs, seafoamed and removed my rack and tire off the roof and now i am getting around 19! I think the rack and tire will stay off now. gotta love the rollin brick!
 
Lifting the XJ cuts the MPG the most. I've owned three. The biggest drop was when I put a 3" lift and 31" tires on an 84 with a 2.8 engine in 1984. I put 4:10 gears in and that helped a little and then when I went to 4:56s I got even better MPG. I end with that set up at about 16 MPG. The 2.8 was gutless.
 
Being a member of NAXJA:doh:

This insues a serious case of inchitis, followed by a need for more armor symptoms, then............well its all down hill from there.:spin1:

You want to save money on gas, sell the jeep buy a honda.
 
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