Custom Tunes.
 

Ok, so I just receieved my invoice for my Edge upgrade to a Gryphon and two custom tunes. I choose a 87 Perf tune and a 91 Perf Tune. I also kept the 87 stock tow(canned tune)

My question is since all the gas stations in the area sale 87, 91, 92 octane. Am I good with the tunes I ordered? Will a 93 perf tune suit me better? I usually run the highest octane offered which is 92.

My perf mods include cat back exhaust, CAI and new gears.

Thanks

Looks like good choices to me!

However you answered your own question and I agree that a 92 perf tune would suit you better over the 91. Doesn't look like much of a difference but I don't wether or not you are using any ethanol blended gas or not?

What we have here in SD is 87 89 92 you go out to the black hills the octanes are now 85 88 91 but out there the elevation is higher.

Lars

Lars said it correctly, Levi.

I want to add a couple of things though.

1. Don't ever request a tune for octane ratings that are higher than the gasoline you have available - you would NOT want a custom 93 octane tune.

2. If you travel to a place in the US that has higher elevation, you are likely to find all octane ratings reduced, as Lars stated about the Black Hills. That's because altitude improves the anti-knock properties of gas. So, if you were to travel to the Black Hills, you could safely run 91 octane with your custom 92 octane tune. (And, you should not have to adjust the timing). I use 85 octane gas when we go to Colorado with my 87 octane tunes.

- Jack

Thanks for the quick reply guys. Is there any drawback to running higher octane gas with a lower octane tune? So is it bad to run 92 octane with an 87 perf tune?

Thanks.

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