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Thread: Octane rating and safety

  1. #1

    Octane rating and safety

    I'm looking for a little knowledge on Octane rating. I have a Gen 5 6.2L with a whipple supercharger and a custom ground cam. There is some question to what octane level the fuel tables were made for. It is either programmed at 93 (as I requested) or 91 (sticker put on the fuel door).

    My supplier of 94 octane is no longer going to be selling high octane fuel. How can I tell by monitoring if 91 octane is safe for the timing/fuel tables written?

    Will there be certain codes set? Or extreme retarding of timing?

    High octane fuel is hard to come by in Oklahoma, but every station in Texas and Arkansas have 93 Octane.

    Thank you for any insight

    Jack.

  2. #2
    Tuning Addict 5FDP's Avatar
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    No codes will be set. You'd likely just see an increase of knock retard if the octane isn't high enough.

    I doubt whoever did the tuning specifically made it for a certain fuel, they just knew you were running premium in it.

    I don't make my tunes any different for the fuels because not every station has 93 octane here. It can be 91, 92, 93 or even 91 with no ethanol. I make the tune so it's safe and don't try to get every last horsepower from the engine.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  3. #3
    Will the computer keep the engine safe or is there an actual chance of destruction?

  4. #4
    Tuning Addict 5FDP's Avatar
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    The computer will always pull timing if there is knock and it will learn if there is knock for prolonged periods of time. There is a high octane and low octane spark table and if whoever tuned it wasn't dumb they would have left room like a factory tune does and has both of those tables with different values. So say the HI table had 16 degrees at full throttle, the low table should have 8 or 10 degrees. That way if it shows knock it can reduce the timing and find a medium between those two values for however long is required based on the knock learn factor.

    If you have HP Tuners, just start watching the data logs.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.