Originally Posted by
kojack
It depends if the car was designed for it. If the car calls for 91 and you use 87, the car will retard timing and you will drop a couple of hp. but its not an inverse reaction with a car going from 87 which is was designed for to 91. you will not gain any hp. Its not using 91 for extra horse power, its using 91 for resisting knock and detonation from higher compression ratios and advance timing. In the micra, 91 is pissing away your money....nothing more. I am a mechanic, and built race engines etc.
Glad to see someone else understands this issue..."money for nothing"!
Thanks...
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View my fuel log 2016 Micra Active manual: 6.0 L/100 km ... 46.9 mpg (Imp) ... 16.6 km/L ... 39.0 mpg (US) ...