Fuel Economy - What do you get out of a tank? (3rd gens only)

[Apollo441]

I got about 513km's per tank on petrol, i'm getting about 600+ on gas which is awesome for the hip pocket and i tank of gas lasts me about a week and half rather than 4-5 days on petrol.

[kiwisimon2006]

I started with a full tank Wednesday last week. Light came on today so I filled again. Distance travelled was 446kms, 80% city driving, 100% grandad style.
The fuel was E10 blend and the cost was $68 for 55.3 litres

It worked out to be 12.4L/100km

Heard I could go further on premium but would that outweigh the 13c extra cost per litre? Would like to hear everyone's thoughts.

I have a 96 Magna TE V6 Exec, 189000kms. Just bought it last week. Getting full service inc timing belt on Monday so will be interesting to see if economy improves. It may not have been serviced properly in a while if log books are anything to go by.