Re: 110 Racing fuel
I have an Audi A6 2.7T as well as the two 2005 XFs and have driven them with mid-range gas (89 octane) most of their lives. I haven't seen any improvement in gas mileage when using premium and any performance benefit is not really noticeable since I don't hammer the cars. Saving 10-15 cents a gallon may not seem much, but I used to drive 25-30,000 miles per year distributed across my three cars and it did add up. Now that I drive a lot less, I am using premium in the XFs and I usually alternate between 1/2 tanks of midrange and premium with my A6. I would never...repeat never....use regular. I also pay attention to any knocking. Note: I have found that gas mileage is worse when I have to use 10% ethanol, that is sold in some states and stations.