Timing/Octane question

[Jackpine]

First, I have to ask: "Why are you using the 87t tune if you're burning 93 octane gas. Are you towing?" If so, then yes - go ahead and advance the timing. You should be able to set it to +3, but I'd start with +2, since your engine is most always "under load" when towing. If you notice no problems, try setting it higher, to +2.5, then +2.75 and finally to +3.0 if things seem OK.

If you're NOT towing, you should really be using the level 3 91+ octane canned tune. In that tune, with 93 octane gas you MAY be able to set the timing to +1, but I'd do it in stages (+0.5, +0.75, +1.0), checking for problems at each step.

- Jack