Anyone gone from 93 to 91? (octane)
 

So I'm still undecided on what to do with the Miata when I move to Cali. I'm thinking take it out there and leave it parked most of the time, but as soon as I get to about the middle of Texas there'll only be 91 at the pumps, and the car's tuned on 93. So...

Just take a few degrees of timing away? Add any more fuel?

Of course, I'm going to keep my 93 octane .msqs saved for when I (hopefully) move back out here or somewhere else with 93.

GA gas is good but not great (not like that Texas 93). You'll need to peel back a bit of timing, but don't forget you've got WI. A little meth in the water will do worlds. I wouldn't get too worried.

That's pretty much it. Your mixture may lean out a bit when you get into the CA gas, but it's impossible to say how much. I'd expand the EGO authority to, say, 10 or 15% and keep an eye on Gego. If you don't already have it, set one of your Megatune gauges to Gego.

As to timing, just pull 3 or 4 degrees and live with it. You can probably leave it alone in the lowest kPa cells so as not to mess with your idle too much.

Thanks for the advice, guys.

Ben - my WI causes a lot of boost creep, so I disconnected it.