parkerdt

My '06 was getting about 280-290 miles/tank prior to 10k miles, and now gets routinely 320-330 I switched to full synthetic (Mobil 1) at 10k.
Too many degrees of freedom to pick a cause. But I'm not gonna switch back to dyno oil to prove or disprove a point.

I'm gonna try this on my '02 Spa which is still on dyno oil at 46k Will run a few tanks on normal mixed driving, do the switch to Mobil 1 and compare again. However, this will not take into account the difference in rolling resistance between Dunlop Winter Sport M3s and Re01Rs. LOL!

My anecdotal evidence over many cars and many years does suggest about a 5% mileage increase coinciding with going to synthetic oil.

But it ain't fact, and your mileage may vary

Dave

kingbriani

Dave, that sounds like it should be a good test on your '02. It would rule out break in and winter/summer fuel if you were able to see a difference. I imagine RE01R tires will have a significant negative effect on mileage though. when are you doing the switch?

ottokrat

My car seemed to reset the ecu at almost exactly 12k miles. Even though I had not recently been in for service, or disconnected the battery, it had all the symptoms of being reset: difficult initial starting, rich smell, lower milage for about 3/4 of a tank. I suspected something so I also checked the emissions test state (via key on for 25 seconds), and that indicated not tested - also a sign of a recently reset ecu.