What Fuel Grade for max BHP on the 35i?????

[Z_Victor1]

Interesting one this..........guys.
Need your help.

Now, most (all?) modern cars (Z4 included) have dynamic ignition timing which will advance the timing as much as possible before 'knocking' commences - thus ensuring max power output.

In the UK, what Octane is recommended by BMW for max BHP output on the twin-turbo engine?

Before you respond, 2 points....
1. I am not asking what octane YOU use, rather what does BMW suggest be used for MAX BHP.
2. Remember, US & UK Octane numbers are different - they are defined differently.

For max BHP, previous BMWs I have owned recommend up to 98 Octane (RON method) in EU & UK.
Inside the fuel filler cap on the 35i, is a plaque recommending 95 Octane.
Inside the fuel filler cap on my 840, is a plaque recommending 98 Octane.

Hmmmm, me, no comprende???

[yabbanoname]

I've been using 95 Oct for 3500 kms, now using 98 oct for the last 500 kms.
The fuel consumption seems to bee less (not very much), the performance ... (don't notice the difference).

[Z4 Beemer]

Interesting indeed. Just checked my fuel filler flap (sDrive 23i), and it does say in big letters 95.

Underneath that it says in brackets 91-98. Perhaps its part of their Efficient Dynamics strategy, and 95 offers the best compromise in terms of performance and economy...