The V8 Owners Forum -

At this time, this does not apply in Australia, but I am wondering if it applies within the U.K.

My understanding is that fuel sold in the U.K, both 95 and 98 octane are now in the order of 5% ethanol blends. If that is the case, or even if it isn't, has anyone noted if the traditional 12.5 : 1 A/F ratio for maximum power has dropped? In other words, if the fuel does not deliver the same degree of energy, is it now necessary to run richer needles in carbs or change the fuel maps in order to run richer mixtures?

I am just seeking information based upon what you have found.

Ron.

Hi
I believe the 98 ron (super unleaded) we get over here is actually is often up to 15% ethanol, apparently you should not put it in your tank if you are going to stand the car for more than 2 weeks as what you are left with after that time is definatly not 98 Ron. The ECU in modern cars is meant to be able to richen the mixture up to compensate, logically I can see this being in the range of the ECU, especially as I suspect they were designed with this in mind, it just makes it drink more.
Best regards
Mike