Just collected my latest batch of pro boost from my supplier, he advised me against using optimax and pro boost together, apparently can actually lead to increased problems with detonation.

i know it sounds strange but his theory was based upon the additives in optimax and pro boost reacting poss losing octane ..rather than gaining, recommended sul and pro boost instead.

The guy has great knowledge of performance cars so im taking the advice seriously, just wondered if anyone else experienced problems running the 2 together??.

 

There has been many debates about this and the official response from Shell was that optimax is "refined" to be 98.6 RON and IS NOT NUL with additives in so there shouldn't be a problem. I run a 93wrx on optimax and millers octane booster and don't have any problem with det at all(My knocklink hardly lights up even at full throttle)