gas mileage questions

This subject has probably been beaten around for a long time. I use my 77 cj5 as a daily driver. It has the original 4.2 with the 3 speed tranny. Does anyone have any ideas about how to get more miles out of a gallon of gasoline? I am not very mechanically inclined but I have some friends who are willing to help. I realize that putting in a newer carb or changing the transmission to a five speed would help. Are there any lower cost or less labor involved options? Ideas Please!!!

 

The easiest thing to do is lower your speed on the highway. The aerodynamics of a Jeep makes going even 10 mph faster much more expensive.

I'm not sure you'd see much difference if you changed to a newer carb or a 5-speed transmission.

I'd recommend that you make sure your Jeep is in perfect tune. I'd also recommend installing a vacuum gauge and using that to help adjust your driving habits for best economy. You could also consider an ignition upgrade, either to the GM HEI system or to the later Duraspark system with the TFI upgrade. A low restriction exhaust system would help. Switching to fuel injection would certainly help. Synthetic oil in the engine, transmission, transfer case and axles will help a little.

None of these things are going to make a big difference on their own, but they should make a noticeable difference when taken together.

 

What gear ratios are in your axle and what type/size tire do you have now? What type of driving, city or highway, do you want to improve your mileage?

What Tim reccomended is the basics to ensure maximum MPG for any vehicle.
Make sure that the engine is tuned correctly. This is the easiest and cheapest step but usually a little time consuming. Replace all old vacumn hoses. Adding a better high energy distributor does help on some engines.
Changing your gear oil in the axles, transmission, and transfer case to a good quality synthetic will also help lower friction in these units. Mobil1 syn gear oil is about $8 a quart and available at most auto parts stores.

 

Make sure you are running the proper pressure in the tires. Other than that a tune up will help.

You are driving a brick, however, and if you want much better mileage, get a car..

High5

 

Keep your foot off the skinny pedal. Nothing is more of a gas hog than fast acceleration. When approaching lights that are turning red, even if they are a ways off, put the tranny in neutral and coast. Using brakes wasts gas.

Look up "hypermiling" on google. Some people get up to double the millage in their cars. Course these are the extreams but you can get some ideas.

But what Tim said will be a good start.

 

I agree with all the above. Knowing what kind of mileage you are getting now would be more helpful for us to help you with any options. They will only get so much...

 

How many miles do you put on your Jeep in a year? How soon do you want your investment paid back? You could spend thousands on ignitiion upgrades and fuel injection. You could have the rotating components smoothed and coated to reduce windage drag of crankcase oil. You could have carbon fiber front clip constructed. Do the math on payback of investment before getting out the checkbook.

Example: Jeep is driven 5000 miles a year. A widget costing $250 will raise mileage from 15 mpg to 17 mpg. Figure gas at $3.50/gallon (I'm an optimist). It will take you 22 months of driving (assume consistent monthy mileage) to break even. Then you'll only save $138 per year for every year after that.

Do what is free: keep your engine tuned, keep your filters clean, check tire pressure, drive more carefully. Save your money somewhere else: eat out less, drink cheaper beer, turn down your thermostat in the winter by 2 degrees and wear a sweater, wrap insulation around your hot water heater, cancel Cinemax, skip the Starbucks coffee...

 

What's a Widget and where can I buy one.

Sounds like a good deal:twisted:

High5

 

The "widget" is a propeller with a generator mounted to your bumper. The faster you drive the more gas you save!

 

"drink cheaper beer" BLASPHEMY!!!!!!!!!!

Some things, such as the simple pleasures of quality beer and driving a Jeep are worth a few extra bucks!!

 

All it takes is an adjustment in your driving habits. The most I could get out of the '72 CJ5 with 258 was about 16 MPG.
The '75 with the 258 was a little better. The '78 with 258 would do an honest 20 on the commute, 24 on the highway.
Bone stock. How much more than that can you expect?

 

I took the expensive route. Bought the jeep like everyone else it was old old an tired at frst. I got about 8-10 mpg. Over a year of issues, I rebuilt the engine, replaced the carb with a motorcraft, replaced the ignition system with motorcraft parts and did the nutter buypass. Removed all emmission controls except the pcv, and cleaned up the electrical system, also runa manual choke.

With the warm weather the jeep now does 75 on the highway, but I still drive it mostly locally because its still a short wheel base jeep.

I average 18 mpg and I had it hit 22 on sever occasions. Not bad for a stock 258 as far as I can tell.

 

18 mpg aint bad,,, I get 19 in my Liberty.

Now Im just curious what my CJ-5.0 will get once it's on the road. Whatever it is,, it wont stop me from driving and enjoying it. Just the price we pay for our toys.