Highest Octane For Stock ECU??

Hi-TecDesigns

To answer the earlier question about the ECU advancing timing...

Using a semi-closed loop system, The ECU will retard timing as knock appears, and it will advance timing back as knock disappears, slowly but surely until either knock appears or it is back to the default timing. The key here is once the ECU has advanced back to the default value, it will not advance any farther. If there is zero knock on 93 on a sunny day, you are getting the best performance out of the engine possible, and placing a higher octane will not increase power (not getting into the oxygenated argument here). Don't make the mistake that the ECU will continue to advance timing beyond the default until it starts to knock, always giving you the most power possible for each tank of gas... it doesn't work that way.

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Modshack

Just as an example (from a 2008 Corvette) there are High octane and low octane timing tables that are selected based on knock sensor output. Without tuner intervention, the high octane table is going to give you the most timing advance adjusted for commonly available gas octane, but no more. Tuners can and will build Very high octane tables to take advantage of 100 octane race gas. Usually the only differences with these tunes are the timing adjustments. More octane + more timing = more HP

High:


Low:

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