high octane fuel + FI, tune not needed?
 

so I have a track day coming up, and some of the guys mixed the 92O and 110O race fuel half/half at the track. I was told the ECU will relearn the high octane fuel and change the spark timing on its own.

Since my car is FI with a custom tune, will I be ok running a mixed high octane fuel at the track? Will my ECU just learn on the fly? Or should I run the car a day or two with race fuel to have my ECU learn?

They ran it fine at the track, saying the car will pull less timing and the car will generally run better with higher octane. No tune needed.

What do you guys think?

The car will not add any additional timing, but it should give you better knock supression with the higher octane which should help @ the track. Wait for others to chime in.

Do NOT run 110 leaded fuel. 100 unleaded will help maintain your maximum tuned power whereas 92 you will most often lose power at the track with timing being pulled to save your engine from detonation. ECU will adjust on the fly. However, I typically reload my map if the dynamic advanced multiplier is not at 1.0 before the first run.

If you are already at max IAM you won't get additional timing from running higher octane. More knock resistance yes so if your 93 is causing timing to get pulled it'll resist pulling more. You didn't mention if it was leaded, leaded fuel will kill your O2 sensors and cats if you have them.

I put 2 gallons of 101 octane Trick in with a tank of 92 0E. It's all unleaded of course, no ethanol whatsoever, and seems to make the engine run crisper during track days while providing knock suppression. This brings octane up to optimal levels for this high compression motor, right around 93.5

It costs me about $12 more a tankful but is worth it. I still average 34mpg on the street.

For reference, I was using about a 25/75 mix high octane to push my octane to around 94 or 95, and it was VP Racing MS109 which is an unleaded oxygenated fuel.

awesome. I will contact my tuner just in case as well. Looks like if I just dump it in with half fuel, should be good then. 93O + 101O UNLEADED.

Ahhhh so excited for my first track day! Car is at the shop half of the time, but finally able to drive it!