Originally Posted by zoopsta
hey there
i have read many threads about this topic and ill say something none of u guys have mentioned (but dont quote me on this - iam just referring to a source)
Now i cant remember exactly, but its along the lines of this:
BP Ultimate fuel is purely 98RON, but Shell Optimax is actually lower than 98, but they add stuff to the fuel to bring it up to the 98 level.
Also, the chemical additive in Optimax (called teluine or something) is left stuck in the surrounds of your fuel tank and other bits the fuel go through (like an unwanted deposit).
I use ultimate myself, a much smoother ride ;)