Rick in Colorado

I just did the first oil change on my JK using Mobil 1. While certainly not scientific, I appear to be getting 1+ mpg better over the same driving routes. Has anyone else had the same experience? Intuitively, it makes sense that better lubrication reduces friction and betters fuel economy (as well as, perhaps, power).

While the onboard mpg indicator may/may not be accurate, it most likely is accurate relative to it's own previous readings.

tgrt

More than likely you had a good tail wind this time.

HULKGREEN

The benefits of a synthetic oil was explained to me this way::::

Imagine running a sprint race ( 100 yard dash ) in a 3 piece suit = conventional oil or dino poop

NOW Imagine running the same sprint race ( 100 yard dash ) in shorts and no shirt = synthetic oil

I have always found this to be an awesome analogy!!!!!!

Windshear

I have not put synthetic oil in my Jeep. I did on my Trans Am and noticed the same 1 MPG difference. I am planning on putting synthetic in manual transmission, transfer case and differentials. Hope to pick up 1 to 2 MPG. I would also use it in the engine, but since you have to change the oil every six months I don't see the cost benefit.

Lorrel

I could believe a 1MPG increase with synthetic, however there could be other factors at work. Mileage could be one. The fact that you just did your first oil change could mean that the rings have seated, and your engine is now more energy efficient. I think ambient temperature could also have something to do with MPG.
I'm a firm believer in synthetic oils, in that I feel they are a higher quality in the refinement process.
The analogy is marbles. While dino oil is like a path of marbles that have the ability to move around, some of the marbles are a bit larger than the others, and likewise a few are somewhat smaller. Some even have flaws and chips in them. While they have the ability to roll around, it is somewhat hampered by the size difference, so there is a bit of rolling resistance. This resistance creates friction.
Now on the other hand, imagine the same area fillied with marbles. These marbles however are indentical in shape and size, and have very little flaws.
You can see the rolling resistance is little if any. Likewise there would be very little friction. This is synthetic.

wolverine_man

I remember doing my first oil change with Mobil 1 last spring. I felt as though the Jeep ran a little smoother. I also remember getting a little better fuel economy but I attributed that to engine break-in.

Where I can honestly say I did gain a mile or so per gallon was when I put back on my front air dam. I absolutely hate the way that things looks on my JK, but I lost 1-2 mpg when that thing was taken off.

tgrt

Awesome analogy.

IGOFSHN

It is all a coincidence. Long term mpg increase just doesn't happen.

SBlair

Your perception is typically correct. By going to synthetic you WILL gain efficiency which translates to MPG. It's more noticeable when you do it a scooter. My Harley's have ran better and gotten better gas mileage after switching to Syn. My 2 stroke RC Airplane engines have smoothed out and I've had to lean them out after switching to Syn oil in the gas.

tgrt

I don't disagree, but in practice what level of efficiency are you really talking about -- 0.01 miles per gallon. I think the real benefit is the decreased wear and the improved lubrication.