Paul Allen

US octane ratings are the average of two different rating (using different ways for measuring fuel octane).

Ultra 94 is 89 motor octance rating, and 99 RON (research octane rating).

So..... Audi's 91 requirement refers to US fuels, don't worry about the 95 number... any US premium fuel will meet that.

AvramD

First of all, I find it expensive compared to others, octane for octane (i.e. comparing their 93 to other's 93). Second, over-shooting the octane rating on a car never helps you, just throws away money.

But as for Sunoco, I find that I *often* used to get bad tanks from them (before I started bycotting them). Also, I consider them dishonest b/c they list "economy, regular and plus" on their big road signs, to make you think it's "reg, plus & super" like at most gas stations, and they price them to "match" i.e. econ will be like $0.01 less than Mobil's regular, etc. So, you go, and either buy regular, and pay more than you expected, or buy econ thinking it's regular, and get a tank of 86 oct. Of course if you're shooting for super, it's the same game at a different octane rating.

Anyway, the moral of this story is, 94.5 might be the highest oct. rating you can buy, but if it's a contaminated tank, I'd rather put Mobil 87 in my S4.

Paul Allen

91 US octane is fine for S4 (same as 95 MOT)

Sandy

When I first moved to Denver, I couldn't understand how the barometric pressures the TV weathermen were reporting were essentially the same as that at sea level (You know, 30 inches and rising, etc.) So I called the TV station and they put me right through to Ed Green (or whoever it was) and he told me they correct the barometric pressure for altitude. In other words they add some number of inches to make the "normal range" the same as sea level.

It would be as if premium gas in Denver was 91 octane but they corrected it to read 95 so it would be the same as at sea level. See. . .there's a little bit of a connection.

Sandy