But has any UK Beemer drivers noticed their cars driving quite different if you use super unleaded (97octane) or normal unleaded (95octane). Obviously your car feels quicker and zippier with the super unleaded, but I have noticed that after filling up with some super after I have been using normal unleaded for a while, my car idles a little slower just for a second? Also at very low revs (below 1300 rpm) my beemer seems to feel a little hesitant and not so smooth? Once above 2000 rpm my car feels pretty lively though.
When I then later in the week fill up with normal unleaded my beemer actually seems to idle much more smoothly and pulls away from low revs much more smoothly, even a bit quicker as well? Except of course once I am cruising at above 2000 rpm my beemer does not feel quite so lively on normal unleaded.
Can anyone answer why more beemer's engine seems to respond differently at different revs on the two petrols?