I just dumped a whole tank of regular (85 I think) into my beloved Z. Because I'm awesome.

I should basically assume it's going to run a little off for a bit but I'm not looking at any serious issues, right? I don't track it or anything.

If I was you, I would go to a paint store and toss in a few gallons of Toluene. It will raise up your effective octane in the tank. Do not buy any 'octane booster' nonesense from a auto store: its weaker and smaller in quantities then the good stuff from a paint store.

Xylene can also used but I have found Toluene easier around me. I would not add more then 2 gallons (keeps it < 20% toluene mix)

Ex:

Toluene (R+M/2) Octane: 114
Xylene (R+M/2) Octane: 117

Average Octane = (Base x Qty1 + Change x Qty2) / (Qty1 + Qty 2)

Example for 16 and 2:

((85 x 16) + (114 x 2)) / (16 + 2)

Which is 88.2, pretty close to 89.

Now, if you are at sea level (DFW) and not altitude, 85 octane is cat piss and I would be a bit concerned about running that in any car tuned for 91. Sure the knock sensor should detect any noise and reduce your timing maps but that is a pretty large drop.

If it was 87 (I hope), its a bit better story and the toluene will get you above 89 and you can rest easier until you get 1/2 a tank left, then go find a sunoco and fill 1/2 with 93 octane.

Finally, please smack yourself for putting in a full tank of 87 octane. This is your Z doing it, not us: nothing personal, and its for your own good. :D

- b

Thanks for the advice.

It's important to note this occurred an hour or two after my wife (not a car person), completely unprovoked by me, comments on how much she likes riding in my car and what a great job I've done taking care of it. I'm a bonehead.