I had a 98 TJ and with a lift and 33s the gas mileage sucked. I switched to a hi-flow air intake, hi-flow exhaust manifold and a hi-flow exhaust and the mpg shot up to even better than the 18 mpg on the sticker.

Now I have a 2013 JKU with an automatic, a lift and 35s and yep - gas mileage sucks. Has anyone had success with upgrading the JK to a hi-flow intake and exhaust? If so - what did you do? What products do you suggest? What kind of mileage are you getting as a result?

My TJ went from 9 mpg to 25 mpg on the highway (no kidding). I am getting an average of about 14 now and would like to get to at least 20.

 

your not gonna see much in the way of gains even if you do both exhaust and intake you may get lucky to see 1 mpg increase.

 

On my 2012 I had a MBRP Off Road Exhaust, on 3.5" lift and 35's I saw about 17.2mpg. Before that I was averaging about 14.5-15.5.

 

Like said above with both those things maybe a 1-2max gains, I mean could get a programmer may help a bit, not 100%.

 

I have a Magnaflow cat back, Rugged Ridge snorkel, Superchips Traildash and switched to 91 octane gas. I gained 1.5 - 2 mpg. Oh, and a K&N drop in filter. But I have the programer set to 91 octane performance. If It was set to fuel economy, I'm thinking I'd gain another mpg.

 

I have a 2013 JKU Rubicon 3.5 lift with 37s. I put an Airaid cold air intake. On the highway at about 70-75 I average 16 mpg. Was thinking about messing with the exhaust but I don't think it will do much. I really can't ask for much pushing 37 Trail Grapplers. Good Luck