Custom Tunes.

[tohi2care]

Won't the knock sensor retard the timing if detonation occurs?

[Jackpine]

Originally Posted by tohi2care

Won't the knock sensor retard the timing if detonation occurs?

I'll answer your question first. Yes, but that doesn't make everything wonderful for the engine. There are other settings that may not get adjusted properly if you're running low octane gas on a high octane tune. And, these problems come up in open loop, when the engine is under load. Not a good time to have them happen.

Now, Levi - you can use higher octane gas with a low octane tune. If the tank is FULL of 91, add 2.0 degrees of timing advance if you are using an 87 octane tune. But, there are other properties of that gas that you are not taking advantage of when you use it in an 87 octane tune. So, you're simply not taking full advantage of the properties of the higher priced (but not necessarily "better") blend. In fact, since we cannot increase the compression in our engines, there's no way we can ever utilize the properties of the expensive stuff properly.

- Jack