Ok, so I'm considering usingg synthetic. My question is does it improve performance and gas mileage in 2012 jk? I really know nothing about it besides that its more expensive and supposed to improve gas mileage. Also is it worth the extra cost and what brand is recommended? Mobile 1?

Sorry for making a new thread but I couldn't find answers to my questions.

 

This should help you, it helped me:

http://www.bobistheoilguy.com/motor-oil-101/

 

I have used Mobil 1 full synthetic on my 94XJ since the first oil change back in 95. When we got the 07 JK back in Oct 06, I switched to synthetic at the second oil change. That said, I still use synthetic on the XJ, and alway have. Reason is since it's so far out of warranty I change the filter and add 1qt about every 4 months, and do a complete change every 2 years. I only put about 20K miles a year. I've never had a problem and still run about 40lbs pressure when up to operating temp.
I recently switched back to dino on the JK using Mobil 5000. The 07JKU is still under warranty, and I do a complete change at 3000 miles or 3 months, whichever comes first. Since I change the oil at these rates, I don't believe it is worth it for me to bear the added cost of the synthetic. The JKU has 40K miles on it and still has 30K or 3 more years of warranty. When it goes out of warranty I'll most likely switch back to synthetic. Again Mobil 1 and go to the same frequency as I do for my XJ.
Don't get me wrong, I do believe synthetic has it all over dino, it's just that I believe that as long as the warranty is in effect, and with the frequency I change the oil, synthetic is just overkill.

 

I been running syn since the beginning, have never noticed a difference in fuel econ. Originally was using Pennzoil full syn but switched to Mobil 1 syn when someone suggested I might not experience 'using' oil with the switch. It made no difference whatsoever. I change it every 3-5k.

 

For me, it's synth not because of increase in mileage (there's little to no tangible benefit there) but for longevity of the oil. I usually change oil/filter every 6k, and it's not cooked.

 

The big thing is It deals with heat better and in cold weather it stay as a liquid and doesn't freeze for easy starts and protection and you can go 10k without a change

 

I recently went to syntethic. I have a Banks intake and exhaust and I have 35s. Just with the 35s I was getting 14.5mpg and with the intake, exhaust and synthetic I am getting 16.2mpg. I did the oil and exhaust at the same time. The intake brought me to 15.3mpg. I hope this helps.

 

This how I see it and the interval I change at.

 

I had the using oil issue to. I started adding a quart of Lucas additive during each oil change and it seems to have solved the problem