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Thread: kr at 8 psi with 11ish degrees of timing knock sensors too sensitive?

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    Advanced Tuner Boosted C6's Avatar
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    kr at 8 psi with 11ish degrees of timing knock sensors too sensitive?

    Im thinking this might be the knock sensors being too sensitive and would like to see a second opinion. this is on 93 octane 8 psi on3 7875 turbo stock ls2


    Boosted c6 7 psi timing test 1.hptkr.hpl
    2007 C6 Corvette on3 single turbo kit on a bone stock LS2

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    It could definitely be real. Not all power adders are the same.. things like exhaust restrictions or if it has a cam matter when thinking how much timing at what boost it will take.

    Is your IAT mounted on the charge side? You are dropping in temp slightly on pulls. I'd definitely put a IAT sensor before the throttle body. I'm sure you know already but its part of the MAF sensor on your car.
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    Advanced Tuner Boosted C6's Avatar
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    Quote Originally Posted by Alvin View Post
    It could definitely be real. Not all power adders are the same.. things like exhaust restrictions or if it has a cam matter when thinking how much timing at what boost it will take.

    Is your IAT mounted on the charge side? You are dropping in temp slightly on pulls. I'd definitely put a IAT sensor before the throttle body. I'm sure you know already but its part of the MAF sensor on your car.
    No cam and the IAT sensor is mounted right before the throttle body
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    It doesn't make sense that you would drop 2 degrees F making 8 psi of boost. Something doesn't add up.
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    Quote Originally Posted by Alvin View Post
    It doesn't make sense that you would drop 2 degrees F making 8 psi of boost. Something doesn't add up.
    Someone told me something about under partial throttle the air is slower and since the air in the pipe is slower it heats up faster because of under hood temps. When in boost the air speed goes way up so it doesnt have time to get heated up by the under hood temps. My car is using a gm IAT sensor.
    2007 C6 Corvette on3 single turbo kit on a bone stock LS2

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    Quote Originally Posted by 09cobalt 2.2 View Post
    Someone told me something about under partial throttle the air is slower and since the air in the pipe is slower it heats up faster because of under hood temps. When in boost the air speed goes way up so it doesnt have time to get heated up by the under hood temps. My car is using a gm IAT sensor.
    That may be true one the pre boost side, but if that was true on the post boost side, there would be no need for intercooler setups. Squeezing the air heats it up.
    Is your IAT sensor with the MAF?

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    Advanced Tuner ttz06vette's Avatar
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    I ended up changing my sensitivity on two cylinders that were causing the issue. I’m able to run 16* now at the top within the powerband with no Kr. I’m using meth though. Think it was my exhaust causing the sensors to react.

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    Have you tried a higher octane fuel and verified nothing is rattling around in the engine bay?

    Things that are weird to me, but may not matter:
    • Dynamic airflow disable/re-enable RPMs are usually set outside the RPM range the motor will use, along with a properly failed MAF, when in SD and super low when we want MAF only. You have 8,192 disable and 0 re-enable. Try re-enable at 8,000.
    • The MAF diags are weird also. Failed MAF, usually the fail hi/lo are 2/1 or 0/0 and the hi/low counts are 1/1. I never really understood why people flip flop any settings related to enable/disable stuff. Changing things in that manner just creates more unknown variables. Most of us cannot see the code running these cars and a smaller subset of us even understand what we're looking at if we can see the code. It's best to follow factory logic with enable/disable settings and sometimes 0 is not the answer. My opinion on this applies to any setting that involves an enable/disable threshold and hysteresis.
    • MAF diags ERT, IGNV, RPM, and Delay, usually left stock.
    • You have 3 VE tables, 2 of them are zero'ed out. Might want to have them all be the same at all times.
    • Spark smoothing is enabled, likely should not be.
    • Your current PE settings are dumping to much fuel at to low of an RPM/boost, in my opinion. Use the Boost PE table and ramp in your fueling with boost as nature intended.

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    Ok its been awhile but i started messing with the car again. Still have bad kr even though im trying to get around 16ish degrees of timing. I fixed the super rich spot on tip in and i satrted using the boost enrichmaent table and still have issues. Im thinking maybe the 93 we have here is just garbage maybe and im going to try octane booster tomorrow

    turbo-ls2-c6-8-psi-test ve change 7.hpt ve log 7.hpl
    2007 C6 Corvette on3 single turbo kit on a bone stock LS2

  10. #10
    Advanced Tuner JayRolla's Avatar
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    Quote Originally Posted by Boosted C6 View Post
    Ok its been awhile but i started messing with the car again. Still have bad kr even though im trying to get around 16ish degrees of timing. I fixed the super rich spot on tip in and i satrted using the boost enrichmaent table and still have issues. Im thinking maybe the 93 we have here is just garbage maybe and im going to try octane booster tomorrow

    turbo-ls2-c6-8-psi-test ve change 7.hpt ve log 7.hpl
    I would try to find some high octane race fuel instead of using an octane booster. Or if you have the fuel system capable run some e85 and switch stoich 9.765.
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