Finally got my Rubi! Now, I have questions.

[alksion]

Geez I didn’t know standard rubicons we’re just getting only a few miles more per gallon than a 392. My foot has been heavy this week and I’m currently seeing under 10MPG haha

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[jellis4148]

Do not waste your time on the cold air intake. They are a waste. You get no MPG or horsepower gains. All you've done is cut a hole in the hood of your Jeep. Those CAI are as bad as angry bird grills to me.

 

[DavidArmen]

The discrepancy for some of us is definitely interesting. I guess I blame my roof rack (133 pounds and an aerodynamic hit) for my never touching 20mpg... but what was your hit? You're still low-mileage. Maybe you switched tires too early before yours was broken in enough and would have started seeing better mileage. I put my roof rack on on day 2, before I hit 500 miles, so I have never driven it without the rack and with a broken-in engine.
Of course none of us Wrangler owners see gas mileage as priority 1. I want to be able to 4wheel, hard. BUT, it doesn't mean I don't care about gas mileage at all. I will buy an all-electric Rube AFTER that technology is tried-and-true, tested in real Rubicon situations for a few years... until then, I wish I was getting 2-3 more MPG.

It indeed is interesting. I got my 21 JLUR last September and it was stock in terms of lift/wheels/tires until this July when odo was at 6k. It’s an etorque pentastar with hard top, tow package and steel bumper group.

Before the lift and tires, I had only minor exterior and interior upgrades with the only thing that weighed enough to have any impact being a winch. i didnt notice any difference in driving characteristics or fuel economy whatsoever with the installation of the winch. i did, however, put half inch spacers in the front when i eventually installed the 2 inch dynatrac endurosport in july.

I never measured or looked closely at my fuel economy but I have the average mpg always on display on the upper left corner of the evic and once in a while I navigate to the mpg page to view current mpg's or to reset it and see what numbers i get when only on the highway etc.

For as long as I can remember, even the day I got the jeep with 8 miles on the odo, the average mpg of the jeep computer has hovered around 14 and I don’t remember ever seeing anything above 20 on the freeways, other than intermittent instances when I reset the computer during favorable conditions such as slight downward slopes or favorable winds.
My highway speeds are normally 70-80 when there is no traffic.

When I eventually got the dynatrac endurosport in early July with the 1/2" teraflex front coil spacers and 1/4" longer mopar front LCA's , even though steering and driving characteristics improved considerably, i still didn't notice or measure any big difference in fuel economy and the average would still hover around 14.

I had the same experience a few weeks later, in late July, when i switched my wheels to 8.5” wide icon’s and 315/70r17 KO2’s. I was honestly surprised that there wasn’t any noticeable change in driving. Maybe it’s because I almost never accelerate to red line? I can perhaps say that I lost maybe 1mpg on the highway but my overall average didn’t change much, even after 2k miles of driving with the new wheel/tire combo (jeep odo is now 8k). I also didn’t lose 8th gear the way some forum members were saying and it doesn’t shift into 8th gear any less than it did before, as far as I can tell. Maybe it shifts down sooner than it did before on inclines but that’s expected. The only noticeable difference to me was the steering wheel becoming very slightly heavier but I am unsure of this as it can be a placebo effect from knowing I have heavier tires than before.

To this day, my avg mpg hovers around 14. It was recently down in to 13.7 because I visited Hungry Valley twice in a week but it’s back to ~14 now. It’s in fact 14.5 as of this very moment.

Right after second Hungry Valley Trip two weeks ago.

Yesterday.

 

[ColoradoMike]

It indeed is interesting. I got my 21 JLUR last September and it was stock in terms of lift/wheels/tires until this July when odo was at 6k. It’s an etorque pentastar with hard top, tow package and steel bumper group.

Before the lift and tires, I had only minor exterior and interior upgrades with the only thing that weighed enough to have any impact being a winch. i didnt notice any difference in driving characteristics or fuel economy whatsoever with the installation of the winch. i did, however, put half inch spacers in the front when i eventually installed the 2 inch dynatrac endurosport in july.

I never measured or looked closely at my fuel economy but I have the average mpg always on display on the upper left corner of the evic and once in a while I navigate to the mpg page to view current mpg's or to reset it and see what numbers i get when only on the highway etc.

For as long as I can remember, even the day I got the jeep with 8 miles on the odo, the average mpg of the jeep computer has hovered around 14 and I don’t remember ever seeing anything above 20 on the freeways, other than intermittent instances when I reset the computer during favorable conditions such as slight downward slopes or favorable winds.
My highway speeds are normally 70-80 when there is no traffic.

When I eventually got the dynatrac endurosport in early July with the 1/2" teraflex front coil spacers and 1/4" longer mopar front LCA's , even though steering and driving characteristics improved considerably, i still didn't notice or measure any big difference in fuel economy and the average would still hover around 14.

I had the same experience a few weeks later, in late July, when i switched my wheels to 8.5” wide icon’s and 315/70r17 KO2’s. I was honestly surprised that there wasn’t any noticeable change in driving. Maybe it’s because I almost never accelerate to red line? I can perhaps say that I lost maybe 1mpg on the highway but my overall average didn’t change much, even after 2k miles of driving with the new wheel/tire combo (jeep odo is now 8k). I also didn’t lose 8th gear the way some forum members were saying and it doesn’t shift into 8th gear any less than it did before, as far as I can tell. Maybe it shifts down sooner than it did before on inclines but that’s expected. The only noticeable difference to me was the steering wheel becoming very slightly heavier but I am unsure of this as it can be a placebo effect from knowing I have heavier tires than before.

To this day, my avg mpg hovers around 14. It was recently down in to 13.7 because I visited Hungry Valley twice in a week but it’s back to ~14 now. It’s in fact 14.5 as of this very moment.

Right after second Hungry Valley Trip two weeks ago.

Yesterday.

Oh, your first photo brings up a damn good point that hasn't been discussed:
Tire pressure.
I like mine at about 40 for highway driving, and I do get at least an extra mpg or 2 when the pressure is 40-42 as opposed to say, 32. Looks like yours are lower than that.
So, here's nominating tire pressure as a potential gas mileage variable for sure!

 

[DavidArmen]

Do not waste your time on the cold air intake. They are a waste. You get no MPG or horsepower gains. All you've done is cut a hole in the hood of your Jeep. Those CAI are as bad as angry bird grills to me.

Every time I see cold air intakes and claims that they add 1mpg, it always makes me wonder why on earth did fca/Stellantis not put cold air intakes on all their jeeps if they could easily get +1mpg? When they spend millions on research and development for lighter oils and mechanisms like the front axle disconnect and other technologies just to gain an extra +0.1mpg… So if they could easily add ten times as much as that by simply adding cold air intakes to all their vehicles, why on earth don’t they do it???

This alone, to me, screams scam, especially when it comes to vehicles such as the wrangler.

 

[jellis4148]

Every time I see cold air intakes and claims that they add 1mpg, it always makes me wonder why on earth did fca/Stellantis not put cold air intakes on all their jeeps if they could easily get +1mpg? When they spend millions on research and development for lighter oils and mechanisms like the front axle disconnect and other technologies just to gain an extra +0.1mpg… So if they could easily add ten times as much as that by simply adding cold air intakes to all their vehicles, why on earth don’t they do it???

This alone, to me, screams scam, especially when it comes to vehicles such as the wrangler.

They are a scam. If you install one and go straight to a dyno you will see a slight hp gain, but once the computer remaps and adjusts fuel and air flow it will go back to the same. You're also correct. If they actually gained some MPG's every manufacturer would install them. That's an cheap gain. They are like fishing gear and any other accessory. They are designed to attract a buyer more than anything. I just couldn't bring myself to cut a hole in my hood.

 

[Jmos4]

Every time I see cold air intakes and claims that they add 1mpg, it always makes me wonder why on earth did fca/Stellantis not put cold air intakes on all their jeeps if they could easily get +1mpg? When they spend millions on research and development for lighter oils and mechanisms like the front axle disconnect and other technologies just to gain an extra +0.1mpg… So if they could easily add ten times as much as that by simply adding cold air intakes to all their vehicles, why on earth don’t they do it???

This alone, to me, screams scam, especially when it comes to vehicles such as the wrangler.

Hi,

All a CAI does is slightly lower your intake air temp, not much performance on a natural aspirated engine, now might do something if it was super charged?

Regards,
Jim

 

[jellis4148]

Oh, your first photo brings up a damn good point that hasn't been discussed:
Tire pressure.
I like mine at about 40 for highway driving, and I do get at least an extra mpg or 2 when the pressure is 40-42 as opposed to say, 32. Looks like yours are lower than that.
So, here's nominating tire pressure as a potential gas mileage variable for sure!

You're tire pressure is supposed to be at 35. Why would you run higher, and risk uneven tire wear or a blow out. They would generate too much heat being overinflated.

 

[rickinAZ]

-One of the options I got was the cold air intake, and while I did get the intake, they didn't do the cutout in the hood, which is pretty disappointing...and the dealer insists that 'my hood doesn't need it'. Figured I'd ask before raising hell.

It seems like the most compelling reason to include the CAI on your factory order is the assumption that they'll make the hood cuts.

 

[RedBaron91]

Adding on to the other MPG discussions here, I've averaged just over 15 MPG in the first 1500 miles on my 21 JLR. Mostly city driving to and from work with plenty of stop signs and lights. Cruising on state highways at 55-60 I can get ~20, but I don't do that enough to make a meaningful difference to my average. The few times on the interstate at 70 I was getting 14...

 

[ColoradoMike]

You're tire pressure is supposed to be at 35. Why would you run higher, and risk uneven tire wear or a blow out. They would generate too much heat being overinflated.

Actually my door sticker says 37; not 35. And the tire itself says 50 is max. Running near full-inflation yields better gas mileage. I have run every vehicle I have owned for 20 years this way, and never experienced a blowout or unusual tire wear--and generally gotten better than sticker specs for gas mileage. So... I guess that's why.

 

[hiimmike]

You're tire pressure is supposed to be at 35. Why would you run higher, and risk uneven tire wear or a blow out. They would generate too much heat being overinflated.

Isn’t it LESS heat because less friction? Less friction also means less rolling resistance so greater fuel economy. I always air up my tires before a long road trip. Slightly less comfortable maybe but don’t really notice and do pick up some extra MPGs.

 

[Headbarcode]

You're tire pressure is supposed to be at 35. Why would you run higher, and risk uneven tire wear or a blow out. They would generate too much heat being overinflated.

Specific tire pressure depends on the physical weight of the Jeep they are going on. A chalk test is a great way of determining the best psi for a happy balance of mpg and even wear/maximum lifespan.

Isn’t it LESS heat because less friction? Less friction also means less rolling resistance so greater fuel economy. I always air up my tires before a long road trip. Slightly less comfortable maybe but don’t really notice and do pick up some extra MPGs.

Yes. Higher psi = less tire flex = less friction and the heat produced. The flipside of that coin is that less friction means less traction is available. Also, too much pressure will accelerate the wearing of the center of the tread, which will negate any added fuel economy gains by having to get new tires sooner.

 

[DavidArmen]

If you have no personal problem driving at 40psi, go for it. I don’t see any big issues being caused by that, other than the typical wandering of the steering (especially at highway speeds) and wearing out only the center portion of the tread instead of having even wear throughout the entire width of the tire.

This is why fuel economy increases, you have a smaller area of the tire contacting the pavement, so less friction and less resistance which amounts to slightly higher fuel economy.

To get even wear throughout the entire width, a chalk test is required, as mentioned previously by another forum member, especially if the jeep got new tires and/or has a different weight than a stock wrangler. However, this defeats the purpose of gaining fuel economy since the correct pressure from a proper chalk test will cause the entire width of the tire to contact the pavement, increasing friction and maximizing traction.

 

[Iowa_Wrangler]

392 here, 10.9/avg. $3.81/gal for 91 octane. NO ETHANOL!

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