|
German cars in general are optimised to run on 98 RON. High performance (high compression) engines, and BMW petrols fall under this category, will give around 2-5% greater BHP (KW) output over the 95 RON fuel. Whether you will notice it is a matter of opinion but I think a very experienced driver would, particularly if he/she knows the car really well. Its definitely measurable though.
In addition the higher the octane the cleaner it burns so emissions are less, injectors are cleaner and milage is better. Again the difference is small so it really comes down to price.
98 is marginally better than 95 but is it worth it? Your choice.
I always use 98 (or higher) if its available.
__________________
 "Do or do not, there is no try!" - Master Yoda
"Always in motion is the future" - Master Yoda
"Truly wonderful, the mind of a child is" - Master Yoda
"There is no passion to be found playing small - in settling for a life that is less than the one you are capable of living" - Nelson Mandela |