Why dont Jeeps get better gas milage?

put on skinny hard tires

replace body with sleeker sheet metal

replace high friction 4x4 drive line with small displacement FWD driveline

lower car closer to ground

oh wait, you could buy a FWD Patriot ,,, and save yourself all the trouble finding the parts to mod a CJ like this

A Jeep is not a car. If you want car-like performance and gas mileage, buy a car. Please don't sissify any Jeeps!

me wrote from a troll saturated privacy service:

Who says a CJ can't get 20+ mpg? It's all in the engine tuning and driving style.

Old Jeeps with the Nutter Bypass routinely get better than

20 MPG and even pass California emissions for newer vehicles.

Even my ZJ gets better than 20 and it's blown.

Doug, how did you get 20+ on your CJ? I doubt I'll ever see that kind of efficiency on my CJ-7. I have a SBC with 33" Bf Goodrich tires. I'm lucky if I get 9MPG. Then again, it's not my commuter car, it's my fun car.

No hold up at all, go for it!

I drive an 86 CJ7 with the 258 ci straight six, basically stock for engine and tune a bunch others for my friends and we all get over 20 mpg or 11L/100KM highway.

Stock the CJ's were rated for 21 mpg, far better than the new fuel injected gas pigs. We wheel alongside folks with the newer TJ's and they are always crying the blues when we use about $15.00 "less" than they do for the same run. The new fuel injection is nice because you don't have to tune them as often, but you pay for the convenience with lower mileage.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail > I would love to have a CJ Jeep but just cant go back to

Besides what the other folks have noted, the Jeeps have the aerodynamics of a brick. Tomes

ok so could they get 30 mpg?

Cant they smooth the aerodynamics down some so that better gas mileage would result?

I'm just proposing some small changes that could really make them more efficient

ZJ.

Only way you could get better milage is with more gears.

I've adjusted the idle down, switched to synthetic, run a bit higher pressure in the tires and cut out any unecissary idling for city driving. On the highway I get about 22-24MPG providing it's not into a headwind. I've gotten as high as 29MPG but that was with a nice tailwind.

One thing I noticed is when driving at certain speeds the ZJ likes to stay in a lower gear. Light tap on the gas will drop the RPMs down and save quite a bit.

For one month I did a little experiment. There are two lights that if I miss them will take about 2-3 minutes to cycle. Just turning the Jeep off gave me another 3-4 MPG just by not idling. Did a bit of thought on cutting out injectors when at idle. Never did go past the thinking stage.

Yes, but it's a nice brick. :)

You really think the difference is the fuel injection and that the 700 pounds more weight doesn't have anything to do with it/

Yes I do because mine gets basically the same mileage fully loaded for a two week camping trip or bare empty, the weight doesn't seem to make a difference.

99% of my mileage checks are running fully loaded for camping.

Now if you want to talk headwind and tailwind, there is a noticeable difference there of a couple mpg.

Running with the front diff spinning up also costs me another couple mpg and the TJ's have no choice on that, where the CJ's have disconnects.

Try the same off-road route empty and with 700 pounds of extra weight and see what difference it makes.

If fuel injection hurt gas mileage then why would car makers in the world of CAFE be using it?

Well on that one $15.00 per run difference with the TJ's, we were bush running from base camp so we were all pretty much empty.

Because you don't have to tune it to keep the mediocre mileage so the emissions are more stable. Carburetor systems need to be kept tuned or they pollute like crazy.

I have owned a brand new carbureted car that got 50 mpg right from the get go.

"DougW" wrote Even my ZJ gets better than 20 and it's blown.

And a TJ's empty weight is about 700 pounds more than a CJ's.

Why do car makers care what happens beyond the EPA certification test? And why would a need to keep the cars tuned, which is revenue for the dealers, be seen as a bad thing?

Hint--they don't get taxed on emissions, they get taxed on corporate average fuel economy. That means that emissions don't hit them in the wallet, gas mileage does.

And you used to be able to buy a brand new fuel injected car that got

58 right from the get go. The highest mileage conventional car ever sold in the US got 68, again with fuel injection.

What abt buying and using one of these? I've even thought abt buying on for my current car and it gets abt 27 mpg..... but this gauge above would give me "real time" info as I drive

Probably not a bad idea, but they won't work with my older OBD. The ZJ does have a milage computer, real-time and average. Fairly accurate, but still a guess based on static fuel pressure and injector timing. Think it also reads the tank since one of the functions is distance-to-empty. I keep a milage log, have since I bought the vehicle. Comes in handy as an indication when things need checking.