3.0D What’s your hand calculated DIESEL mileage?

[SolarWizard]

Ok I bought a set of axles out of a rubicon gladiator with 600 miles on them

Seems like I should be able to truss the front and be pretty close to stock gearing wise on 37?

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[GARRIGA]

I have 1500 miles. 37" BFG KM3s with 2.5" lift. Last tank I got 22.0mpg with about even mix of interstate, highway, and city roads.

This is what the “can’t justify the cost MPG” brigade don’t get. Go big. It matters. Plus you have all that torque to move all that mass.

Ultimately, this will likely prove to be a great platform for those pushing 40 assuming those D44s get some help. Was hoping the diesel same with 60s from the factory. Perhaps down the road they create a variant with exactly that in mind. Just don’t forget the Adaptive Cruise Control. Some of us want our DD beefier than others with that infrequent run off-road knowing less worries when you do.

 

[Motoristx]

Edit, 4/27/2020 Looks like I had the wrong transmission numbers. I fixed them with the numbers off the 2020 spec sheet.

Ok I bought a set of axles out of a rubicon gladiator with 600 miles on them

Seems like I should be able to truss the front and be pretty close to stock gearing wise on 37?

It will be slightly different. Use this link to type in your own numbers. http://www.grimmjeeper.com/gears.html

play around with it

these are the ZF 8HP75 transmission numbers.


1st=4.71 2nd=3.13 3rd=2.10 4th=1.67 5th=1.28 6th=1.00 7th=0.84 8th=0.67 Rev=3.30

stock @ 70 MPH would turn 1798 RPM
37's on 4.10's @ 70 MPH would turn 1768 RPM

 

[JLURD]

I expected change. but with estimated mpg's at 22-29 25 avg I thought I would see much closer to that 25 number especially so far I've been 80%+ all highway. Acceleration feels great doesn't feel like I have added any weight what so ever. From driving mostly sport cars most of my lift I will say This jeep is truly a joy to drive. Its not carving out corners and its not a racer but damn if this doesn't put a smile on my face everytime I get behind the wheel even if I am just backing it out of the driveway.

I think the more realistic comparison is with the delta between a 3.6 or 2.0 running 35s or even a JK for that matter. Your mpg seem a bit low compared to mine on 35s, but you’re still achieving a 20-30% mpg increase over alternative drivetrains running the same setup.

 

[SolarWizard]

What about in comparison to the overland or sport tires?

 

[JLURD]

Alright folks, here’s one for the history books. I just filled up my 3.0 with an indicated 24.8mpg running on 37” Milestar Patagonias with AEV Borah beadlocks totaling 117lbs per corner...figured that might be a bit optimistic as I was doing my hand calculation but low and behold, the hand calc shows 28.6 mpg! I don’t even want to believe it, but I’ve been filling the tank to the top of the neck despite the carbon vapor filter risks because I don’t like unaccounted variables in these calculations. For reference, I’m running the pats at 30psi, my hwy/cty mix was 70/30, highway speeds ranged 65-70 with no cruise control, I’m running 0.25oz/gallon opti-lube xpd fuel additive, I’m on the stock suspension still, my driving was bidirectional for the longer highway segments with no consistent tailwind, and I’m running 135lbs of sprung mods on the front axle plus about 100lbs of sprung mods and gear on the rear axle. Fuel was shell diesel but their pumps say its “not a shell product” so who knows on that front. Ambient temps were 30-52 degrees F through that tank. If this rig comes even close to repeating that performance as it further breaks in, I will be happier than a pig in shit.

 

[CAC]

I just did a round trip from Bend to Portland and back, same day. 380 miles round trip.

3.0 Rubicon with AEV spacer lift and 37" Ridge Grapplers on AEV Borah wheels. I'm usually 5-10 over speed limit, so most of the day 65-75 and crossing over a mountain pass twice.

26.5 mpg indicated by the computer. 24.998 hand-calculated.

I'm pretty impressed, I just drove normal, no hyper-miling.

 

[2020 Diesel JL]

Alright folks, here’s one for the history books. I just filled up my 3.0 with an indicated 24.8mpg running on 37” Milestar Patagonias with AEV Borah beadlocks totaling 117lbs per corner...figured that might be a bit optimistic as I was doing my hand calculation but low and behold, the hand calc shows 28.6 mpg! I don’t even want to believe it, but I’ve been filling the tank to the top of the neck despite the carbon vapor filter risks because I don’t like unaccounted variables in these calculations. For reference, I’m running the pats at 30psi, my hwy/cty mix was 70/30, highway speeds ranged 65-70 with no cruise control, I’m running 0.25oz/gallon opti-lube xpd fuel additive, I’m on the stock suspension still, my driving was bidirectional for the longer highway segments with no consistent tailwind, and I’m running 135lbs of sprung mods on the front axle plus about 100lbs of sprung mods and gear on the rear axle. Fuel was shell diesel but their pumps say its “not a shell product” so who knows on that front. Ambient temps were 30-52 degrees F through that tank. If this rig comes even close to repeating that performance as it further breaks in, I will be happier than a pig in shit.

thats great.
I don't think the diesel has a carbon vapor filter. If it does I don't know what it would be doing.

 

[JLURD]

thats great.
I don't think the diesel has a carbon vapor filter. If it does I don't know what it would be doing.

Yea someone on here claimed it does but I don’t actually know for certain.

 

[SolarWizard]

Given your post would I be doing an MPG detriment by running 4.10s with 37s or actually enhancing it?

 

[JLURD]

Given your post would I be doing an MPG detriment by running 4.10s with 37s or actually enhancing it?

Given that it’s holding 8th on the highway with the 3.73 gearing on 37s, 4.10 will likely drop mpg.

 

[Megatron JLU]

Just re geared to 4:56 waiting on 40s. Been driving it around with the 37s and currently getting 18 mpg avg. 90% highway driving.

It drives awesome with this gear ratio and 37s. Starting to think I should of went 4:88s for the 40s. But I wanted it to stay as strong as possible.

I've been babying it only going up to 65 mph to break in the gears and that's as good as I get.

 

[JLURD]

Just re geared to 4:56 waiting on 40s. Been driving it around with the 37s and currently getting 18 mpg avg. 90% highway driving.

It drives awesome with this gear ratio and 37s. Starting to think I should of went 4:88s for the 40s. But I wanted it to stay as strong as possible.

I've been babying it only going up to 65 mph to break in the gears and that's as good as I get.

Not bad for the gearing, wheels, tires, added weight and plumbum of the right foot!

 

[Megatron JLU]

Not bad for the gearing, wheels, tires, added weight and plumbum of the right foot!

I have not got on it because I can't. So I've been driving it like a grandpa and still 18 is the best it can get. That's pretty good in my book.

 

[JLURD]

I have not got on it because I can't. So I've been driving it like a grandpa and still 18 is the best it can get. That's pretty good in my book.

Well now that is interesting because I never go anywhere without a couple full-throttle pulls and still manage mid to upper 20s on 37s. I imagine the same reason pats are so quiet also cuts down on some of their rolling resistance, but not by THAT much.