jet fuel like Driller probably uses
ROTFLMAO! :laugh:
TECHNICALLY it's not jet fuel but I have been known to use an octane booster. Shhhhhhhhh....!!!
Seriously, what you need to know is the Mark VIII has 2 knock sensors, one for each bank. The PCM 'listens' for the slightest beginning of pinging and will agressively pull timing to control knock.
The stock A/F ratio is quite rich throughout most of the power band. Under normal driving in a stock Mark VIII with normal atmospheric conditions, the knock sensors will likely
not detect any pinging and you may not notice any performance hit or mileage difference when using a lower octane fuel.
However, not all drivers are the same and not all 'regular' gas is the same. Add the changing effects of temperature and humidity and you could easily have conditions that are prone to causing knock. Especially so on 'tuned' cars with a more lean A/F ratio. The knock sensors should detect even the most inaudible pinging and the PCM will subsequently pull timing to prevent engine damge. IF the PCM pulls timing, performance and mileage WILL suffer. It is quite possible for the PCM to proactively pull timing and the average driver would not notice the difference unless he is tracking the mileage closely.
I always run premium fuel. To me, the additional cost of $0.20 per gallon is not significant. With the current cost of fuel at $2.60 per gallon, the additional 7-8% cost does not deter me from choosing premium.
It should also be noted, my HD F150 runs on a premium fuel tune by Lonnie and gets 15% better mileage - more than enough to make up for the additional cost.