Regearing JK 2 Door 6 Speed
05-30-2011, 04:11 AM
#11
JK Junkie
Join Date: Jul 2008
Location: Lakewood, OH
Posts: 3,017
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Yeah, I've found a huge difference in mileage between travelling at 55-60MPH & doing 70MPH & over.
In my stock 2-door 6 speed with 3.21s & 32" A/T tyres I get about 18-20MPG city & 25-26MPG higway at 55-60MPH (if the road's reasonably flat), but as soon as I notch it up to 70-75MPH & throw in a few hills it falls back down to 20-22MPG. There's a long, flat stretch of motorway in my daily commute with a limit of 50MPH & when I sit at that speed in 6th with the motor just turning over I can get around the 28MPG mark, so from my experience 55MPH seems to be the speed where wind resistance really kicks in on the JK with it's brick shape, near-vertical windshield, big fender flares and all the other un-aerodynamic stuff hanging off it (and that's a stock 2-door, let alone a modded 4-door with big tyres, steel bumpers & winches, armor & all the other stuff weighing it down & causing drag at the same time).
In my stock 2-door 6 speed with 3.21s & 32" A/T tyres I get about 18-20MPG city & 25-26MPG higway at 55-60MPH (if the road's reasonably flat), but as soon as I notch it up to 70-75MPH & throw in a few hills it falls back down to 20-22MPG. There's a long, flat stretch of motorway in my daily commute with a limit of 50MPH & when I sit at that speed in 6th with the motor just turning over I can get around the 28MPG mark, so from my experience 55MPH seems to be the speed where wind resistance really kicks in on the JK with it's brick shape, near-vertical windshield, big fender flares and all the other un-aerodynamic stuff hanging off it (and that's a stock 2-door, let alone a modded 4-door with big tyres, steel bumpers & winches, armor & all the other stuff weighing it down & causing drag at the same time).
You can make enough power to cruise at 50mph at 1500 rpm, and 70mph takes 2300 rpm to cope with modest winds and small grades such as overpasses. It takes as much horsepower to cruise a JK at 70mph as it would to propel a Corvette at 100mph.
Best advice is always to slow down for better efficiency as stated above.
05-31-2011, 09:55 AM
#13
JK Enthusiast
The only thing I haven't replaced under my JKU is the front driveshaft. And low-and-behold, it's broke. I've ordered a new HD one, but in the meantime I've been driving without it... Wow, my milage went from 15+- to 18+-... On e-way I used to get about 13 at 70, now getting 16 +