Engineering_guy
Back a few years ago when I was at the most competitive stage of my go kart racing, my old man, who is an industrial chemist, took samples from all the different providers in town (including the 100 ron stuff from united) over the course of a month and tested them all with a gas absorption spectrometer, the results were that the bp 98 was better by a good margin. I cant remember the specifics, but the components of the bp lent itself to a better torque curve across the range. We tested these results with back to back runs on an engine dyno and were validated.
I agree with this - a mate of mine who is a Chemical engineer who also has a love of cars, did similar tests with the BP Ultimate (98), United 100, V Power, Caltex Vortex 98 and a regular unleaded BP 91, and found that the fuel that outperformed the others was BP Ultimate. On the dyno it had a greater torque curve in the midrange to top while also having a low EGT.
(Funnily enough, BP 91 (regular unleaded) had the lowest fuel consumption, even out performing the higher octane fuels with fuel consumption.)
BP Ultimate all the way - I was using it in my CBR250RR before I had the MR2 and have been using it in the 2 ever since I've had it. Remember, these cars with 3SGTE's were tuned (ECU and timing) in Japan where they have much higher octane fuel (100 RON) as regular fuel compared to here.