Racing fuel? as in 110 Octane?
My car ran fine on Premium 93 there for a while, but I switched back to normal when gas prices were skyrocketing. The engine really doesn't act too different with higher octane. The concept behind race fuel is that, because racecars generally have MAD-high compression ratios, the fuel needs to burn SLOWER in order to realize the larger stroke, etc. Low octane is good in low compression engines, where the gas needs to burn quickly to fill the larger amount of space and exit in a timely manner. That is what octane #s mean in gas. This is why the good majority of vehicles with blowers/turbos from the factory call for Hi-Octane. Those railcars at the track with blowers the size of our engines NEED the race fuel to even run.
My theory on a Zetec running extremely-high octane gas is this. The fuel will fail to combust all the way, throwing unused gas into your exhaust. Your pipe will become coated in it, O2 sensors will fail, spark plugs will foul up,valves will be coated in varnished gasoline, and a match to your tailpipe will cause flammability issues. Because the engine is not firing properly, there will be a DRASTIC loss of power.
Too little octane, however, and you will get something called 'preignition'. This is where the gas 'bangs' before it is 'squished'. VERY HARSH ON THE VALVETRAIN! This is most undesireable, but rarely occurs today, due to standardized gas octane levels.
Overall, don't go much higher than 93 octane, or you're just asking for trouble. I'm finally putting that year of working on little Briggs & Strattons to use. Hope I helped!
