Custom tune question

[Riceball1]

Originally Posted by JackandJanet

I think we're on the same page now, but he was asking about using 93 octane gas with an 87 octane tune.

Quote: "I was wondering if you can just change the octane setting to run 93 octane on the 87 performance tune."

I said yes, and he could probably bump the timing to gain a bit of power to offset the increased cost of fuel, but it would not be as good as a true custom tune.

You said, Quote: "The answer is that TECHNICALLY you can run 93 octane with an 87 calibration. However, you run the risk of detonation even with retarding the timing."

And here, I think is where we crossed ideas. But, I now believe you were thinking he should not put 87 octane gas into a vehicle that is tuned to run 93 octane (and that's why you mentioned "retarding the timing").

But, I understood you were saying not to put 93 octane gas into an 87 octane tuned vehicle, or damage could result. And, I was puzzled by your comment on retarding the timing. Also, I'm pretty sure Northern SuperCrew thought he should either replace his fuel tank contents with 87 octane (OK, but wasteful) or raise his tune to 93 - which would be bad, since he'd be burning 91 octane in a 93 octane tuned truck.

So, all is well, now that we are communicating again. Riceball and Northern SuperCrew are you with us now? It's OK, just not particularly efficient, to burn a higher octane gas in a vehicle tuned for 87. And, if you do it, you can advance the timing a bit. (The Edge/Gryphon manual even gives you guidelines here as I remember).

- Jack

All is good

I was just wondering if it was possible to change the timing on a custom tune. Many times when I go to Wisconsin you will find Mid Grade 91 or even 93 octane cheaper than 87. Maybe they just don't move it as fast as Reg.
Thanks for the help.


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Bob