Gooseybhai: I spent over 12 years hanging around a service station (fam bus.), and at the end of the day....all it comes down to is how you drive your car. I see a lot of muppets on the roads...zooming / start /stopping / tail gating for no reason and this wastes gas. It like that guy who races past you just to end up being stuck at the same red as you and/or stuck behind the slower car as you waltz past doing the same constant speed. Dont even start me on the muppets who floor it when the lights go green to only end up behind you later.700 - 800km per tank full. What sort of vehicle, what size tank are you talking here.?
Depends on what your car is tuned to, 98 will get you slightly more kms, but you will only notice this on long haul and perhaps notice 'around town'. I know some people who have got 700-800kms on a long distance trip using 98 and that was 4-5 years ago !
Semaj: 700 - 800km per tank full. What sort of vehicle, what size tank are you talking here.?
SteveON: I have a 2004 Impreza, its tuned for 98 with a 40L tank. Currently it costs 91 $80-90 and 98 $90-100 to fill.
I have been testing this for the past 8 months, I get about 440Km on 98 and 350Km on 91.