HIgher octane is better only if the car can adjust it's timing accordingly. So if the limit of the cars management is an advance curve for 97RON them 98 or 99 RON will make your car slower
Sorry I thought they where linked. Surely if the ECU detects Knock it would alter the cam timing as well? And if it does it would work in reverse when higher octane fuel is used. The way I understood it is that the ECU constantly try's to advance (to a degree) to gain best performance and the pulls back when it detects knock.
Both my 330i's run better with shell Vpower and both Pink now and again on "normal" fuel.
I find this very interesting and would like to know more.
yes they are but vanos controls (via the ECU) when and how long the exhaust and inlet valves open / close
the knock sensor(also via ECU) will determine at what point to fire the spark sooner for 95 ron and a bit later for 99 ron
My opinion - standard octane fuel (95RON or less) should only be used on Carb-based injection systems due to systems involved
If you want to extend the life of your fuel delivery components (pump, filter, injectors) and engine as well as maintain maximum mpg, higher octane should always be a pre-requisite
It doesn't alter the lobe profile the valve only opens for the same time, if it opens earlier it closes earlier. Twin vanos can alter the relationship of the cams to each other too.
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