Not that I really care because I romp the hell out of my car but I have noticed that my gas mileage is gradually depreciating tank by tank.
I probably get something like 11/18 City/Hwy … What does everyone else get?
Depends on your driving style… if you stay in the low RPM range, you can be in the upper teens to low 20s if you’re doing mostly highway speeds… Your mileage sounds like what I’m getting in the city (with heavy traffic) while driving in sport mode most of the time (because it sounds amazing and the quality of music has generally degraded over time)… I’ll check when I get back, but I drove in on sport mode today, through heavy traffic, and I think I ended up with something like 11-12mpg… if I’m driving in the slower sections of the area or in the city city (25-35mph limit due to speeding cameras, etc), in sport mode it’s more like 9mpg… in regular mode it’s more like 13-15mpg.
Same experience I had as well. On all hwy I remember seeing an all time high of 26.5, all city best I saw was 15. Averages as I didn’t care much and like doing hearing the exhaust was city 12-13 / hwy 22-23 / mixed 16-18 sounds about right from my recollection.
I will note this is after the exhaust, carbon clean, new injectors, and msds filters. Without the maint and minor modifications the results were 2-3 mpg worse in all conditions. So if you have a light foot mods can increase mpg and your range, heavy foot well you know 
but you will have more smiles per gallon.
Car: 2008 S6
Gas: 93 Octane
Location: Mid Atlantic USA
Modifications: custom 2.75 catback exhaust and MSDS air filters
Wheels: Stock
Tires: 275/35/19 Conti DWS
Most recent major maint: Updated IM, Carbon clean, and two new injectors
Best: 26.5
Worst: 7.5
City Avg: 12
Hwy Avg: 22
Mixed Avg: 16
I get 20.4MPG at 75mph, drops to 18.9 at 90mph. This is averaged over multiple hours on a highway run. City driving is disastrous so I’ve stopped counting. But it’s probably 12-13 over a tankful. Usually about 250 miles/tank in the city.
Edited: (Hey, I can edit now!)
Work: complete top-end work (carbon clean, plugs, coil packs, fuel injectors), IM with flaps removed, JHM intake spacers. Otherwise stock.
Location: BG, South EUR
Gas: 95 RON
Might be bet to post up mods, and location/elevation and gas , and any major recent maint, so is an easier compariso. Are you stock? I have edited mine to include.
2008 S6
New Motor New Transmission
Mods: JHM tune, KN Filters
20" Rims
City; 13 roughly 258/tank
Highway: 18.5 378/Tank avg 85mph
Yeah I just came back from a short lunch run/driving break, and it was 8-9mpg for that duration lol… So yeah, all just depends on what you’re doing. I was in normal until it was warmed up, then into sport mode for the sound…
and regarding mods, I have the basic suite of JHM mods minus LW CP and LW Rotors
It varies for me, based on a ton of factors.
Leaving the selector in D and driving purely highway, I’ve gotten as high as 20mpg. Using Sport mode or paddle shifters, and being heavy-footed, it can get closer to 12. I don’t think I’ve ever had a tank go below 12mph though.
I’ve noticed in increase in MPG since my JHM tune and overhaul, but honestly I don’t know how much exactly. I’d say I get about 30 more miles on a tank of gas than I used to (so I guess it’s about a 1.5mpg increase)
I’d estimate that the vast majority of my tanks fall between 14-15mpg
Sounds reasonable. I’ve averaged 12.7mpg over the last 10k miles or so
hey my IM flaps are all mangled up, to the point I cant epoxy them shut…I see you jsut removed your entirely. Does it still run nice and smooth? I am leaving my tumble flaps in, but want to remove the tract changeover flaps-is that what you did?
I had mine removed completely (before the idea of epoxy ever crossed my mind). It does run nice and smooth. Still feels torque-y at 2-3K, but you don’t get an extra kick above 5K or so.