i used to get that shitty number when i was putting in 87 oct
2012 Fuel Consumption Guide from Natural Resources Canada actually states that GC uses premium gas... (when our 2012 manual says to use 87)
Anyhow I've been putting in 94 from petro and i'm down to 10.9 in city. Yes it depends on how I drive, and well I sometimes get as low as 9.4L and high as 13.
If you really want to know how to figure out your L/100KM
Do the following (got this from my service manager at my dealership)
1. Pick a gas station you go the most and pick a pump from that station.
2. Fill it to full until it clicks. (Make sure you stop at the first click)
3. Drive 100km and go back and fill again.
Repeat several times and get the average.
This will give you what your average consumption is.
Only engine mod I have is CAI btw.
My service manager and I went for drive on the highway for 100KM and found out that I was getting 7.9L which is very close to 7.8. So there is nothing hyundai will due for me.
In the city, I'm usually sitting at 5th gear if I'm driving at 60km. Some guys I know will even sit on 6th.
Turbo engine runs better with premium gas regardless of what your manufacturer says.
For anyone that knows how to use gear ratio for better driving please let me know.
First Gear Ratio

1) 4.23
Second Gear Ratio

1) 2.47
Third Gear Ratio

1) 1.67
Fourth Gear Ratio

1) 1.23
Fifth Gear Ratio

1) 1.00
Sixth Gear Ratio

1) 0.79
Reverse Ratio

1) 3.99
Final Drive Axle Ratio

1) 3.91