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Thread: Can i run 87 on a 229/242 cammed ls3?

  1. #1

    Can i run 87 on a 229/242 cammed ls3?

    2010 Camaro LS3 M6 E38. All i have done to it is the cam essentially. Stock intake, stock engine(aside from the cam, pushrods, springs, and trunnions), tsp exh manifold, straight pipe. Since the compression ratio hasnt changed, cant i still run 87? Low octane spark tables are stock as well. 229/242 .600"/.600" 112 LSA 109 ICL
    Last edited by Z107; 09-20-2022 at 04:27 PM.

  2. #2
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    Timing will have to be reduced to prevent detonation, mostly in high RPM areas

  3. #3
    I figured, have the option to get free gas for life, but its 87 octane. Had to double check here to see if my cam was too large for it. Whats the amount i should decrease the table by? 5%?

  4. #4
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    What do you mean still run 87? LS3 with a stock cam requires 91. On 87 it would eventually knock it's way to running completely off the low octane spark table. And it might still knock running on that. You could copy the low octane table to the high and try 87 but watch for KR.

  5. #5
    the owners manual says it can take 87...

  6. #6
    Tuning Addict 5FDP's Avatar
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    Yeah it can but it likely says it recommends 91+ for best performance.

    Say you do win free gas, why not just chase it instead of only running 87 octane because I sure as hell wouldn't with a modded engine like that. Run half 87 and half 93, then it's at least 90 octane.
    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.

  7. #7
    Thats what i was thinking about doing. Remember doing this when i started out with E, so why not 87. Thanks for the input guys.

  8. #8
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    You might also have to take out some timing in the mid range. Log your knock retard and take out some timing anywhere you get more than a few degrees of retard. I big cam probably lowers your dynamic compression enough so you may not have to take out very much timing except at higher RPM.