Gas mileage in the CJ's
- Thread starter flatie46
- Start date
SteelHeadz
Super Moderator
Yep! gear ratio has a lot to do with it. I get around 8-9mpg , 10 if i'm lucky. However, i also have some mild performance in the engine like the cam, intake and a 750 Edelbrock 4 barrel with the stock axle gears. 
82CJ7JEEP
New member
Currently with an engine that I feel is out of tune (timing and carb need to be set) I am getting almost 15 on the highway at 50-55mph. I have a AMC 360 with a stock 4 speed, I am geared at 4.10's front and rear with 33X12.5X15's. Hope this helps.
P.S. Steel where did you get the manifold for the four barrel? I have a 600 CFM I would like to put on but can't find the manifold???
P.S. Steel where did you get the manifold for the four barrel? I have a 600 CFM I would like to put on but can't find the manifold???
SteelHeadz
Super Moderator
Edelbrock. I'm currently using the performer intake and carburator but later on i'm thinking of swapping the intake with the airgap series.
Crazy4diesels
New member
My 78 CJ7, 258, 3 spd std, 4-something gears, 29 inch tires, used to get around 12-15 MPG depending on what kind of driving I did. My 05 TJ (4.0, 6 spd std, 3.07 gears, 31 inch tires) gets 15-20 MPG. I guess all that fancy computer control equipment adds a little bit of mileage. Both Jeeps seem to get worse mileage if pushed on the highway. "Pushed" meaning 55-60 for the CJ and 65-70 for the TJ :lol::lol: . I guess we must remember that we're cruising down the road on a concrete block with a tent on top. Ahhh, yes... The aerodynamics of a refrigerator box. -John
82CJ7JEEP
New member
Thanks Steel, I will look into it. Is the "air-gap" intake that much better, or is it just a cooling factor? I know the performance is better the cooler the fuel, but I am not convinced in the cramped engine compartment it will make that much of a difference. If you get it please post as to the performance you get.
John your right, Jeeps probably aren't much different aerodynamicly from the front or the side. I was hopeing to kinda hear a comparison between the 304 and the 258 as far as fuel mileage. I didn't post the thread that way so it's my fault, but anyway. Personally I like the sound of the V8 but in my opinon the 258 will out last it and take more abuse. I wouldn't care which I owned, both are goood engines. Fuel mileage eats into the family budgit so I'm just tryn' to figure out which would be best for me.
I was hopeing to kinda hear a comparison between the 304 and the 258 as far as fuel mileage. I didn't post the thread that way so it's my fault, but anyway. Personally I like the sound of the V8 but in my opinon the 258 will out last it and take more abuse. I wouldn't care which I owned, both are goood engines. Fuel mileage eats into the family budgit so I'm just tryn' to figure out which would be best for me.
Weylyn
New member
For the record, I am still running the same engine that GOD and AMC put in my 73. I have a 258 with a 3 speed. I avg about 13 to 16 depending on what I am doing. When I made the trip from Arizona to Missouri, I avg 16 on the open road at 58 MPH. I still run the single barrel and only mod is I put a fancy air cleaner on it. This was with 31in tires. I think I have 4:10 gear but don't quote me.
Yea, but that'd be expensive. Might pay off in the long run though. I know you can tinker around and get your mileage numbers up. I've even got a video on how to make a hydrogen generator for less than $50 that may double your mileage [results may vary
]. The thing is I've heard different stories over the years. I've heard that you could milk more gas mileage out of a good running well thought out six with electronic ignition. Then I've also heard that the small V8 will do better because it's not having much load on it at all being in a lightweight jeep body and frame. I know the newer jeeps get better mileage and they're pretty cool, but I've always had a thing for the older CJ's.That sounds like a good project, if you found a roll over it'd work out pretty good. I've been seeing some project jeeps in my area but like you I really don't need something else to work on. [ a man's got to be realistic sometimes] I'd like to buy one that runs and drives pretty good, some rust wont bother me. I'm not interested in pretty paint or chrome. I'll find one when the times right. Gonna try and learn more about 'em till then and keep driving this worn out chreokee.
I bet it feels strong with those gears and the 304. It's a good lookin' jeep I might add. I saw a 69 CJ-5 on cragslist the other day that had the V-6. I wonder if they do well on gas.
I posted this before I bought my CJ-5. After tinkering with it and driving it on some short trips around the block [ about 1.5 miles ] and to the store. I've gotta say the 304 don't seem to be too bad on gas. I've just got a 6gal boat gas tank in it untill I finish all the welding that way I can pull it out easily. I know I haven't driven it enough to give it a good test but I don't think my Cherokee with the 4.0 would have done this good. I haven't owned a V-8 since the early 90's. The last one I had would pass everything but a gas station. I know this thing needs plugs, wires and such.
83-cj-7=383-stroker
New member
superj
Well-known member
the wife's stock 93 (4.0, auto, 3.07 gears, stock tires) gets 15ish in town and 19ish on the highway at 65-70mph
my almost stock 87 (4.2, auto, 3.07 gears, 31" tires) gets 13ish in town and 17ish on the highway at 65-70 mph
if we do 60-65mph, we get a solid 20-21mpg out of both on the highway
my almost stock 87 (4.2, auto, 3.07 gears, 31" tires) gets 13ish in town and 17ish on the highway at 65-70 mph
if we do 60-65mph, we get a solid 20-21mpg out of both on the highway
