rsilvers129

How fast do you average when you do that?

Brimstone

Picture says 58 mph, and for a < 2 hr. drive which I can do on the highway cruising so long as its not all up hill. (its probably more like 28-29 mpg anyways)

rsilvers129

If I locked ACC onto 60 and drove far enough, yes, I would expect it to reach 30.0 indicated MPG.

Since I got 28.9 and was going 65 to 75.

But for my car, true mileage was 9% less than what the Audi indicates.

Gsrjc

oh okay... interesting that you haven't seen a difference. cool to know.

nly04

I believe the indicator alway show better MPG than manually measure and calculate miles per gallon. My last trip from San Francisco to Disney Land (410 miles). When I fill up before I start the indicator show 560 miles. On my way to Disney, starting from 6AM I stop one for breakfast and restroom and I have just enough gas to get there, the indicator notice I still have about 30 miles. So 410 miles trip plus 30 miles left for a 21 gal tank equal to 21 mpg which is not bad for this size of SUV, but the indicator show 24.5 mpg.
On my way back, I did very much the same but without stopping since I left Disney at 7PM, when I got home indicator show 25 mpg and and reminder show 50 miles left. By the way, HWY5 speed limit is 70 mph, but my average speed is 80mph.

rsilvers129

Read this: https://www.consumerreports.org/fuel...d-premium-gas/

Gsrjc

I will say I used to use 7/11 gas here on the east coast for many years because it was cheap. I still used premium gas but after about a few years the ML350 I drove ended up having issues. In the end needed a whole new fuel injection system and fuel rail and injectors because it was all clogged up. I don't know if it was related but ever since then I stick with premium if needed and only get gas at reputable companies like shell or Sunoco.

rsilvers129

Yes on reputable companies, for which 7/11 is not one of them that keeps your engine clean. Consumer Reports reviewed AAA's test and found that TOP-TIER affiliated brands were better for keeping engine and injectors clean. However, there is no difference between 87 and 91 or 93 in terms of the detergents added to gasoline. The 87 will keep the engine just as clean as 93. Everyone has to use premium if it is required for their car, or else you can damage your engine. Q7 is not one of those cars.

BigKutta

I have heard arguments that generic gas comes from the same refiners as the name brands. I have heard no need for premium etc etc. Guys, stop overthinking this...feed your luxury car what the manufacturer recommends, and go with a reputable brand.

rsilvers129

Well I know the answer now after all this research. AAA tested brands. Turns out that TOP-TIER has 5x the EPA-mandated detergents, and that makes a significant difference. And it also turns out that, while it is possible for a maker to add those detergents without paying for the TOP-TIER license, none of them do! So get TOP-TIER gasoline. All of the major brands are TOP-TIER, as far as I know. And all TOP-TIER companies have agreed to use the same level of detergents in their 87 as in their premium.

However, with a Q7 at least, 87 vs 91 is just personal preference on if you want to pay extra for the octane, which the car sometimes, but not always, needs to make the maximum rated HP. The hotter and drier it is out, and the more often you load the engine close to 100% (especially towing), the more often the car benefits from the extra octane. I am trying to measure the difference with my iPhone accelerometers. I have not finished my testing yet, but I would bet a lot that no one reading this could detect which gas is in the car from driving it.

AAA: Not All Gasoline Created Equal | AAA NewsRoom