Just thought id throw this one out there, but im pretty sure the M54 (2.2i to 3.0i) engines adopt a 'Lean Burn' map when running on higher octane fuel which helps explain the economy increase and power increase.
This is toally un-scientific as ive only had the 'plugs out twice now. Firstly was at ~35k (2 previous owners before 28k). The car was probably run exclusively on '95 octane but upon checking they were the normal brown colour.
At my inspection 2 last night, after running the car exclusively on 97/99 for a while, the plugs were now a slight whiteish colour which shows the engine is running leaner. Therefore the engine utilising (quite well might i add) the extra octane numbers to lean off the mixture without any knock... Ive had plenty of cars before claiming to do this with knock sensors etc, but none with quite so profound effects! Well done BMW!
This at least proves why my economy increases with 99 giving more proof that Super Unleaded really does 'pay for itself'!
This is toally un-scientific as ive only had the 'plugs out twice now. Firstly was at ~35k (2 previous owners before 28k). The car was probably run exclusively on '95 octane but upon checking they were the normal brown colour.
At my inspection 2 last night, after running the car exclusively on 97/99 for a while, the plugs were now a slight whiteish colour which shows the engine is running leaner. Therefore the engine utilising (quite well might i add) the extra octane numbers to lean off the mixture without any knock... Ive had plenty of cars before claiming to do this with knock sensors etc, but none with quite so profound effects! Well done BMW!
This at least proves why my economy increases with 99 giving more proof that Super Unleaded really does 'pay for itself'!