24+ mpg after 6 weeks on the road

[Elsuperbeasto64]

I have read and counted all of your comments up to this point. There seems to be a sharp line of those below 20mpg (more like 15-19) are Rubicons and Sport S with Max Trailer 4:10 gears and those above 20mpg (20-25) are mostly Overlandsers and those with 3:73 gears. Facts only ' )

I agree 100%. The Rubis and max tows are getting murdered by their final drives. Taching out to get 75.

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[Sazabi19]

I agree 100%. The Rubis and max tows are getting murdered by their final drives. Taching out to get 75.

My 20-22mpg is with a Max Tow Maybe it's the 33's getting you guys? Extra weight from addons?

 

[ShadowsPapa]

My 20-22mpg is with a Max Tow Maybe it's the 33's getting you guys? Extra weight from addons?

I'm noting a bit less mpg now with the extra weight up front - the bumper at about 80 pounds, the winch at about 80 pounds and then the steel skid plate - that's a lot of weight! The original bumper is so light I can carry it over my head with one hand and that plastic air dam? what, a pound?
So I've added over 160 pounds to my truck and I have to suspect the air flow was impacted, too.
It's not a lot, and it has gotten colder since I installed that stuff, but still, adding something between 160 and 200 pounds to the front end of the truck............ it dropped it 1/2", too.

 

[KurtP]

its the tires making the biggest difference. I'm debating trying to sell the Falked Mud Terrains while they're brand new and going with a more road biased tire, then getting a second set of wheels with 35's or something. The daily driving on MT's isnt something I especially need, even though the falken's are excellent tires.

 

[DreamedofaJeepSomeday]

its the tires making the biggest difference.

Three things really. Final drive ratio, tire size and weight, driving style.

 

[Len]

Hey Len. What part of VA are you in? I'm in Norfolk and looking for advice on trustworthy dealership for service and upgrades (Mopar lift).

I'm in VB

 

[Len]

I'm in VB

I currently go to the dealership off VB blvd. I haven't had issues with the service department. They seem to be on top of things. The service manager is Vicki, she is very helpful, at least she has been with me.

 

[KurtP]

Three things really. Final drive ratio, tire size and weight, driving style.

final drive doesn't affect it in the least. The difference between 3.73 and 32.2" tires and 4.10 and 32.4" tires is about 150rpm's at 65mph. At 85mph it's about 200rpm, which matters not at all.

It is entirely inconsequential. It comes down to tire tread design and weight in this case, along with amount of throttle required to keep the tires moving pushing the truck into open loop fueling. I haven't tested it, but I'd bet a bottle of ketchup that regearing a rubicon/mojave to 4.33 or 4.56 would actually improve mileage. Id bet another that swapping passenger car tires from the Overland would net similar results.....

Staying out of open loop fueling maps is the key to better fuel mileage...increase power, or reduce gearing to compensate for loads or rotational masses.

 

[DreamedofaJeepSomeday]

final drive doesn't affect it in the least. The difference between 3.73 and 32.2" tires and 4.10 and 32.4" tires is about 150rpm's at 65mph. At 85mph it's about 200rpm, which matters not at all.

It is entirely inconsequential. It comes down to tire tread design and weight in this case, along with amount of throttle required to keep the tires moving pushing the truck into open loop fueling. I haven't tested it, but I'd bet a bottle of ketchup that regearing a rubicon/mojave to 4.33 or 4.56 would actually improve mileage. Id bet another that swapping passenger car tires from the Overland would net similar results.....

Your point that tire size, mass, and tread pattern are more significant than drive ratio is well taken. However to say that 150-200 RPM is entirely inconsequential does not quite square wtih experience.

 

[JTRUBI]

Man, I wish I got numbers like that. I’m getting 15.7L/100kms right now. Rubi, manual trans 37s but I drive pretty spirited.

 

[Len]

So here is an update on my mpg for my stock Rubi. I took a road trip to visit my son in Ohio and I took the 81 back. The speed limit was between 55 and 65 so I set my cruise to 63 and rolled with it. I ended up get a record high fo me of 20.2 mpg which gave approximately 400 miles to.a tank of gas. That is the best I ever have gotten. Typically I cruise at 72mph and I get around 18.2 to 19.0 mpg (that's a guess since I never really clocked it). Not sure how others get 24+ but hey good on you for it! I usually don't pay attention to my mpg, but after reading all the post I decided to pay attention this one time. Keep on Jeep'n!

 

[KurtP]

Your point that tire size, mass, and tread pattern are more significant than drive ratio is well taken. However to say that 150-200 RPM is entirely inconsequential does not quite square wtih experience.

have you methodically tested fuel mileage where the only change you made was a reduction in gearing?

 

[DreamedofaJeepSomeday]

have you methodically tested fuel mileage where the only change you made was a reduction in gearing?

What I have done is compared instantaneous MPG when shifting between 5th and 6th at highway speeds. While traveling at constant speed on level ground.

The difference in ratios between 5th and 6th is 1.13, nearly the same as the difference between 3.73 and 4.10, which is 1.10.

 

[KurtP]

What I have done is compared instantaneous MPG when shifting between 5th and 6th at highway speeds. While traveling at constant speed on level ground.

The difference in ratios between 5th and 6th is 1.13, nearly the same as the difference between 3.73 and 4.10, which is 1.10.

Your point is taken, but it isn't the same, despite all logic indicating it would be.

 

[Sazabi19]

So here is an update on my mpg for my stock Rubi. I took a road trip to visit my son in Ohio and I took the 81 back. The speed limit was between 55 and 65 so I set my cruise to 63 and rolled with it. I ended up get a record high fo me of 20.2 mpg which gave approximately 400 miles to.a tank of gas. That is the best I ever have gotten. Typically I cruise at 72mph and I get around 18.2 to 19.0 mpg (that's a guess since I never really clocked it). Not sure how others get 24+ but hey good on you for it! I usually don't pay attention to my mpg, but after reading all the post I decided to pay attention this one time. Keep on Jeep'n!

I usually drive at 60 or the posted speed limit if higher (yes I use the right lane and get passed lol). Our trucks seem to do alright up to about 60mph but above that mileage starts to tank, especially 70+. Add in ANY uneven road or an incline and it goes down a lot. If you want better mileage, usually going slower in our truck helps. Being a brick it sucks trying to be forced to go faster and faster, lots of resistance.

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