Jeep Blackout - What fuel injector product are you using? I've owned a couple sport cars besides pretty much always having a Jeep, and I've never used any injector product...

OP - 38 psi? When I got my new axles and regeard and went to 37's the first road trip we did was 180 miles each way, and the ride wasn't very good, you could feel every little bump in the road...

Half way on the return to home I pulled over and checked the psi and the guys had inflated them to 39 psi!

as soon as we got home I grabbed my ARB air down tool and I lowered it to 28 and the ride was wonderful, it was better than stock and better than with my 33's.

i know your talking about gas mileage, but how is your ride quality? And how did you come up with such a high psi?

matthew

 

Great question. I typically air up all my vehicles (Jeeps and Pickup) during the winter months to protect against pressure loss in the cold weather. Once the warmer months come back, I would air down to 34psi or so in the JKUR. Ride quality is rougher with the higher inflation for sure. I am with you in that I too feel every bump in the road. As a truck guy, I am a Chevy guy so it's been IFS for me. With the JKUR, I chalked up the rougher ride to having a solid front axle.

 

Know whats absolutely hilarious about all of these mileage threads? There is no way to get an average. Jeeps are customized. Jeeps are driven with different right feet, in different environments with different tires.

When you get unmodified, stock, cars giving variable mpg across the nation, how can modified vehicles compare? If the owner wants mpg, leave it completely stock. Changing tire size or type means your rig is no longer bone stock. Tires alone can drag mpg down by 2 or more. Not even extra lights, roof rack or a winch. Keep the windows up; doors on; AC off. Slowly accelerate up to speed of less than 65 mph; coast instead of braking; time your lights in city traffic. Try not to be the lead vehicle that pushes air for others, draft if possible.

Drag cd of cars range from mid 26 up to 34 with lower number cd the better. Stock JK has cd of 50.

 

It seems to me it is just simple aerodynamics. Pushing 80 mph with a JK's profile takes a lot of power which equals more fuel. The corn liquer they waste by putting it in gasoline here does not help. Seems like I read long ago that once you are moving a lot of the power an engine uses is just from pushing the air aside.

I have seen 18 mpg at 60 with a tailwind, and 15 driving the same road with a strong headwind. Different speeds would affect it the same way.

Plus I do not feel the JK, at least the 2 door, handles all that safe at 80+ anyway. Unless I feel like jumping on the gas for a brief time, 70 mph seems a comfortable speed for the handling limitations.

Be careful fellow jeepers because any required rapid directional/braking change in a JK at 80+ might cause a high pucker factor. At least compared to a sporty car.

 

I generally get much better mileage just driving around on little two lane routes that are just two lanes where the limit is like 50

i guess people just need to realize that they bought a brick aerodynamically wise.

matthew

 

You are very lucky doing 80MPH and not getting a blow out tire and rolling over.

I recommend checking the MAX rated speed on your tires. Most off road and AT tires are rated about 85mph MAX SPEED.

 

I have been using STP products. I can hear and feel the difference in power when I haven't used them regularly. If anything they are improving the grade of your gas and making sure you're running cleaner.

Also here are some speed recommendations for different sized tires.







Obviously from discount.

 

Nitto AT I have are rated S and there's no way I'm touching that in my jeep without a hemi swap.