Originally Posted by ALPINEX
Well seems I've misworded something. I don't have a pinging now, the manual states to use 87 or lower octane, as 91-93 will cause a pinging. The question then relates to whether or not that info in the manual applies when the predator is added, or if its safe to run the 91. Sorry for the confusion fella's, regardless some good info here!
Higher octane gas will definitely not cause pinging, there's just no benefit to using a higher octane fuel than the engine was designed for. When we're talking about the octane rating of gasoline, it's a measurement of the knock resistance of the gasoline. The higher the number, the more resistent it is to knocking/pinging. See the link below for more information
With a tuner though, you probably want to use the highest octane gas that is practical (i.e. 91-93. Race gas would be excessive, and expensive) so that you can use a relatively agressive tune to get more power, and maybe better fuel economy (the octane wouldn't be what causes mpg to go up, if anything it'd be maybe a leaner A/F or different timing. If nothing else, the higher octane would give you a wider range of A/F and timing to work with before getting knocking/pinging)