Don't ditch the Jeep thread!!!

[tobycat1]

If high gas prices have got you down, don't ditch the jeep yet! This is the thread for fuel savings and tests, I will be testing several ways to get better mpg. I will show you a couple figures

this is what you get for a trade in on a 2000 jeep with 100000 miles
Condition Value

Excellent - less than 5% of all vehicles
$6,175

Good
$5,620

Fair
$4,695

Say you sell it for 5,500, and get a brand new Corolla for 15,000. It cost you 9,500 for better mpg!

08 corolla mpg - 27/35, we'll call it 27 knowing how most people drive
00 wrangler mpg- maybe 12-20 for most, we'll call it 15.

the average vehicle is driven about 12,000 miles per year, assuming $5 per gallon on gas, you will save $1778 each year on gas. BUT, based on this info, it will take over 5 years before you investment starts to pay off, and by then you may want a new car. So stick with the Jeep and just try to make it more fuel efficient for less $$$

First off, my baseline

BASELINE:
99 TJ
4 Banger
33" tires
3.73 axle ratio
flowmaster 50
CAI
MPG-----11.5

TEST #1- upgrade to 4.56 axle ratio
99 TJ
4 Banger
33" tires
4.56 axle ratio
flowmaster 50
CAI
CITY MPG----- test in progress

[tobycat1]

BTW, if you have anything you want tested and its within my budget, I will probably test it

[bigjohnjeep]

I for one appreciate you posting this thread. Most people don't "run the numbers" to see that buying a different vehicle would have to be an even swap dollar-wise to see any immediate savings in the increase in fuel mileage. Good job, dude!!

[jeeptales]

I live in West Texas so anywhere I go I have to drive is some distance.

Granted when I stay in town I don't rack up many miles.

But when I travel that is another story:

• Midland is 18 miles
• Big Bend is 165 miles
• Amarillo is 235 miles
• El Paso is 242 mile
• San Antonio 285
• Dallas is 332 mi
• Houston is 440.00

And that is with out ever leaving the state!

I drive a 2007 Jeep Wrangler Rubicon on a 2 1/2" BB Lift on 33" MTRs with the stock 4:10 rear end around town 11-12 mpg on the highway 14-15. But my list trip to El Paso I purchased the Lucas Fuel Injector Cleaner with each fill up and the trip averaged 17.85mpg for the whole trip.

This is good to know because I'm about to add the Mopar 4 1/2" long Arm Lift Kit and go to Cooper 35" tires. I know at 35" the recommended Pinion and Sun gear ratio is 4:56. SO any thing I can do to pick up MPGs I'm listening.

When I pay off my Jeep I might buy a 2009 Honda Civic for road trips that do not include wheeling, but even if gas was over $8.00/gal I would never give it up.

[Jerry Bransford]

TobyCat1, are you sure you want to regear your TJ to 4.56 with 33" tires with your 3-speed automatic? With that transmission and tire size, I think you'd be a lot happier with 4.10 due to the really high rpms you'll get on the highway with 4.56 and 33" tires with your 3-speed automatic.

I was recently running a 5 speed transmission with 35" tires and 4.88 gearing which produced ideal highway and offroad engine rpms. But I recently converted the 5-speed to the same 3-speed transmission you have and the rpms are now excessive on the highway so I now cruise at around 60 mph, no higher than 65 at the very most if traffic won't let me go 60 mph.

My 4.88 and 35" tires produce about the same engine rpms as your 4.56 and 33" tires would so I wouldn't go 4.56 for 33" tires unless your TJ is strictly a trail Jeep like mine is pretty much becoming.

[jeeptales]

Originally Posted by Jerry Bransford

You sure you want to regear your TJ to 4.56 with 33" tires with your 3-speed automatic? With that transmission and tire size, I think you'd be a lot happier with 4.10 due to the really high rpms you'll get on the highway with 4.56 and 33" tires with your 3-speed automatic.

I was recently running a 5 speed transmission with 35" tires and 4.88 gearing which produced ideal highway and offroad engine rpms. But I recently converted the 5-speed to the same 3-speed transmission you have and the rpms are now excessive on the highway so I now cruise at around 60 mph, no higher than 65 at the very most if traffic won't let me go 60 mph.

My 4.88 and 35" tires produce about the same engine rpms as your 4.56 and 33" tires would so I wouldn't go 4.56 for 33" tires unless your TJ is strictly a trail Jeep like mine is pretty much becoming.

Well my plan is to drive it and make a road trip or two to do my review on the Lift kit and tires. I plan to track the MPG and see how it does before I swap gears. But when I have it on the rack I have got to fix that front diff leak that has been driving me crazy since March.

I have an automatic transmission 4 speed.

[Jerry Bransford]

Originally Posted by jeeptales

Well my plan is to drive it and make a road trip or two to do my review on the Lift kit and tires. I plan to track the MPG and see how it does before I swap gears. But when I have it on the rack I have got to fix that front diff leak that has been driving me crazy since March.

I have an automatic transmission 4 speed.

I must have been typing my response to Tobycat1 as you posted. My response was aimed at Tobycat1's post, sorry for any confusion.

[AzTJ]

Toby also has a 4cyl....

[tobycat1]

Originally Posted by Jerry Bransford

TobyCat1, are you sure you want to regear your TJ to 4.56 with 33" tires with your 3-speed automatic? With that transmission and tire size, I think you'd be a lot happier with 4.10 due to the really high rpms you'll get on the highway with 4.56 and 33" tires with your 3-speed automatic.

I was recently running a 5 speed transmission with 35" tires and 4.88 gearing which produced ideal highway and offroad engine rpms. But I recently converted the 5-speed to the same 3-speed transmission you have and the rpms are now excessive on the highway so I now cruise at around 60 mph, no higher than 65 at the very most if traffic won't let me go 60 mph.

My 4.88 and 35" tires produce about the same engine rpms as your 4.56 and 33" tires would so I wouldn't go 4.56 for 33" tires unless your TJ is strictly a trail Jeep like mine is pretty much becoming.

Its been done about 500 miles ago, and I'm very happy with it. I am getting to speed as fast as before while only pushing the pedal down half as much. I drive mainly city anyways and 65 mph is about 3000 rpm, which isn't bad. I went 75 up to the casino and back an hour away up in the mountains and I only used 1/4 tank, before gears I used 1/2 tank. So i'm happy.

[tobycat1]

Originally Posted by AzTJ

Toby also has a 4cyl....

yep, if I had a 6 cyl my ratio would be numerically lower by quite a bit.

[Jerry Bransford]

Originally Posted by Jerry Bransford

TobyCat1, are you sure you want to regear your TJ to 4.56 with 33" tires with your 3-speed automatic? With that transmission and tire size, I think you'd be a lot happier with 4.10 due to the really high rpms you'll get on the highway with 4.56 and 33" tires with your 3-speed automatic.

I was recently running a 5 speed transmission with 35" tires and 4.88 gearing which produced ideal highway and offroad engine rpms. But I recently converted the 5-speed to the same 3-speed transmission you have and the rpms are now excessive on the highway so I now cruise at around 60 mph, no higher than 65 at the very most if traffic won't let me go 60 mph.

My 4.88 and 35" tires produce about the same engine rpms as your 4.56 and 33" tires would so I wouldn't go 4.56 for 33" tires unless your TJ is strictly a trail Jeep like mine is pretty much becoming.

Edit: Nevermind, I just caught on that you have the 2.5L four-banger, thanks to AzTJ. 4.56 is the ratio you want with that engine, carry on.

[Jerry Bransford]

Originally Posted by AzTJ

Toby also has a 4cyl....

Thank you, I missed that he had the 2.5L.

[jeeptales]

Originally Posted by Jerry Bransford

I must have been typing my response to Tobycat1 as you posted. My response was aimed at Tobycat1's post, sorry for any confusion.

Sorry I should have see that too!

[nicolas-eric]

Originally Posted by jeeptales

I have an automatic transmission 4 speed.

i have this tranny and 35s with 4.56 gears. in my area it´s gread, but if i´d live in the montains i´d like to have a 4.88.

[4.0l sahara]

Id like to see what the gears do for mpg.

[Rawkon]

just make sure you are redoing your speedo gear when changing gears or tire size. with my 33s and 3.73s and 3 speed auto with the 4.slow i average 15 to 17mpg. before i changed the speedo gear i thought i was getting much less.

[tobycat1]

I didnt re-do it with the 3.73, but I did the math to compensate.

[bpowa]

i added a e fan and correct speedo and now get 11.8 mpg... sigh.. i dont know what is happening.. i drive lightly 3.73 with 32'' tires..

everything is tuned up.

is there a way to check voltage from the 02 sensos to see if they are not burnt?

[tobycat1]

Originally Posted by bpowa

is there a way to check voltage from the 02 sensos to see if they are not burnt?

4 or 6 cyl? and there are these diagnostic machines they "sell" at auto stores that can tell you if there is a problem most of the time, you can return them after you use them.

[Rawkon]

i have all new fluids in my trans tcase and axles, fresh true flow air filter and oil. also running an e fan. If you can get a thermal gun and check the temps in your exhaust that would check for restrictions. how many miles on your jeep?? i have 50k

i also sea foam my motor and fuel on a regular basis. when was your last tune up??

[tobycat1]

My 1st tank of gas is at 1/4 of a tank so the initial test is almost done, Its getting at least 15 mpg, but not sure what the exact will be because my gas gauge is never quite right, and changes. When I fill up next i will see how many miles i got per gallon i put into it.


For my next test I will take out the CAI and put in the stock box with a new filter and see if it gets better mpg with that. does that need oil?

[TJ_Bleu]

'99 TJ SE 5 speed. 79k miles, bone stock. Just did a tune-up (plugs, wires, cap, and rotor). Last tank 306 miles 15.9 gallons = 19.2mpg. This was mostly on 2-lane back roads at ~45-50 mph. A lot of the time with top off.

I think the best way to increase your mileage is to ditch the top and doors.

[distortedtj]

Originally Posted by tobycat1

For my next test I will take out the CAI and put in the stock box with a new filter and see if it gets better mpg with that. does that need oil?

You will only have to oil it if you get an oiled filter such as K&N. Your best bet is to use a AC Delco filter from AutoZone or simalir auto store near you. It has been proven to do better than "aftermarket" drop in filters.

Good luck.

[bpowa]

Originally Posted by Rawkon

i have all new fluids in my trans tcase and axles, fresh true flow air filter and oil. also running an e fan. If you can get a thermal gun and check the temps in your exhaust that would check for restrictions. how many miles on your jeep?? i have 50k

i also sea foam my motor and fuel on a regular basis. when was your last tune up??

i seafoamed it. its has 50k.

toby the cheap obd 2 scanner only reads check engine codes.. it only reads it when it totally fails.

[Rawkon]

how are all your gear fluids and air filter?

[tobycat1]

The result is in! 15mpg, thats a 3.5 mpg increase

[bpowa]

Originally Posted by Rawkon

how are all your gear fluids and air filter?

the filter is a k&n and its clean.. I did not change my diffs yet I bought it used. tranny seems good, the fluid is still red/pink. oil is every 3k.. its at the dealer now getting a main seal and gaskets. so the oil would be changed.. I wanna switch to full synthetic but i'll wait another 3k since the oil change included in the main seal. the tires are aired up 38-40 psi. I know its a bit high but im trying to save gas.. the treads are wearing evenly.. I doubt the steel wheels make me loose 3 miles per gallon.

[tobycat1]

Originally Posted by bpowa

I doubt the steel wheels make me loose 3 miles per gallon.

I wish I had the money to test that right now. switch to alloy allum.

[NY94YJ]

Could a MOD Split this thread? I'd like to follow Tobycats progress, bpowa's issue could be another thread.

Please feel free to delete this post either way.

[bpowa]

Originally Posted by NY94YJ

Could a MOD Split this thread? I'd like to follow Tobycats progress, bpowa's issue could be another thread.

Please feel free to delete this post either way.

scheesh.. lets make this 3 threads.. another one for your complaining.

j/k

I would stop adding to it...just for you.. although I am just advocating about if it worth keeping a jeep with bad milage.. although I am not selling mines..