06Estukay

For boost, maybe. For N/A, if the timing is advanced to the point of knock, chances are it's already well past the point of peak power. Especially on stock compression ratio. It's nice to have the extra octane for the extra bit of safety.

myflys2k

So what happens when you run 91?

06Estukay

If you run 91, head for hills and hide!!!

C63AMG

Are you saying you couldn't squeeze more power from an NA F20C if timing is advanced to take advantage of 94?

myflys2k

So my point is if you're tuned on 94 and you run 91 you'll detonate like crazy. How do you know that the gas you are buying that is 94 octane is actually 94 octane? Be safe and tune on 91 and run 94 for track IMO.

06Estukay

Nah, I've run shitty gas in a pinch. Haven't gotten any knock counts with it.

myflys2k

Maybe because the 94 you're running isn't actually 94

06Estukay

Haha I think you're missing the point.

You can advance the timing past the point of maximum power and still not get knock.

FluKy15

I tune on 91 and use 94 as well for the extra insurance. I have been to areas where 94 just isnt available, i prefer to not take the chance. My recent track day as shannonville also makes me feel like i need the petro 91. I put in shell 91 and it didnt feel right at all...

C63AMG

Are you sure about that?