Actually, despite my appreciation for people who use the recommended fuel in their cars, higher octane burns at a *lower* temperature than lower octane. Additionally, "proper" high-octane gas (i.e. gas that isn't ethanol blended to achieve the octane rating) gets there with higher levels of aromatic compounds that will increase carbon build-up if the car isn't built for it….and whether or not our cars are is up for debate, but they're not super-high compression engines.
'99 528i ('98/12 build). 174,000km BY29428/Royalrot
Breaking My Wallet since 2009
Mods: Stoptech SS brake hose, 280piece toolkit resting on trunk floor, Beisan VANOS seals
'99 540i (grandfather's)