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Thread: Why KR at cruise? and Timing pull at WOT but no KR?

  1. #1
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    Why KR at cruise? and Timing pull at WOT but no KR?

    OK guys I think I understand some of this but not near all. On the first log I have KR at cruising speed, but none at WOT. Why would it KR at cruising RPM and not WOT?
    On Race 1 I have no KR but timing is pulled? something is pulling it?




    LT1 383 forged 11.4 diamond pistons, AFR 195, Comp 238/246 605/618+4 110 Pacesetter LT, 36 Bosch, 3600 Circle D converter, 390 on 9" ford, 58mm T body, ported intake, 24x LS1 ign.
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  2. #2
    Why is your B1 LTFT all over the place? I am guessing you have an exhaust leak on at least 1 side, making it add fuel. Timing can be pulled for multiple reasons. What are your IAT's running at on a cruise? On just that race 1, you hit nearly 120, so my guess is maybe address the intake air temp as well.

    I am really new at this though too. Where are you at in S.Il? I am in Alton.

  3. #3
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    I have a 3.5 in alluminum after market air intake and I think it's getting heat soaked and sending iat high. I moved iat to the air filter, but no change, I am in the proses of extending air filter out of the engine compartment to factory filter placement. I will see if that helps. I had not noticed the LTFT And sure didn't know what would cause it. Thanks.
    I live by Mt Vernon.

  4. #4
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    IAT temp is responsible for 5 deg of the timing. That table is really conservative.
    The KR at cruise is really odd looking. I'd bet it's mech in nature. I have to admit to not knowing anything about LT1 knock sensors. Same as LS1?
    You also have burst knock active in the tune. We usually zero all of that out.
    What car is this in? Sounds like fun!
    Ron
    Y2K C5 A4 Coupe (10.78 @ 127) Cathedral port 6.2
    S476 L33 5.3 69 Nova 8.76 @ 158 Drive to the track street race car
    06 Cobalt SS bought new

  5. #5
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    Yes it is a fun car, it's a 95 T/A convertible, black with flames. Just finishing it and as you can see got some small bugs to work out.

    The LT 1 knock sensor is like the LS1 (not the 2 wire with bolt hole in the middle) but the one that goes under intake, the LT has pipe thread, the LS has metric thread.

    Mechanical as in? Not sure what that could be? So mine is conservative? Is my timing conservative also?
    Thanks

  6. #6
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    Quote Originally Posted by RonSSnova View Post
    IAT temp is responsible for 5 deg of the timing. That table is really conservative.
    The KR at cruise is really odd looking. I'd bet it's mech in nature. I have to admit to not knowing anything about LT1 knock sensors. Same as LS1?
    You also have burst knock active in the tune. We usually zero all of that out.
    What car is this in? Sounds like fun!
    Ron
    I am looking for "burst knock" don't see it, could it be labeled something else in HPT? d it be Knock Learn? I did notice my tune is set for 2 knock sensors? I think I only have one I will check.
    Last edited by 540gts; 06-03-2014 at 08:25 AM.

  7. #7
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    I relocated the MAF and the IAT and the temps are much better below 80*, but still have some retard in this new log? I did notice my tune is set for 2 knock sensors and I think LT1 LS1 F bodies only have 1? still haven't found "burst knock" but I will keep looking.

  8. #8
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    Cool car. The LT1 is vortec based, right? If I recall, they like around 34 deg total timing. And that's what you are telling it.
    If you have your IAT now down closer to 80 deg, The IAT table won't pull any timing. But it will at 95 degrees. You can alter that table. What was the ECM out of? Prob ok to not have it pull timing until 120 or so. You just watch for KR.

    Burst knock is located under Spark/Retard. Upper right in the display window.
    LS ECM assumes 2 knock sensors. I saw where you can choose. Never seen that before!

    By mechanical, I meant the knock sensor might be responding to the mechanical noises the engine makes causing false knock. I would imagine the old SB makes different noises than an LS on the inside.

    I was going to convert my old school rat motor over to EFI with an LS based setup. But decided to just yank it and go LS turbo instead.

    Ron
    Y2K C5 A4 Coupe (10.78 @ 127) Cathedral port 6.2
    S476 L33 5.3 69 Nova 8.76 @ 158 Drive to the track street race car
    06 Cobalt SS bought new

  9. #9
    My guess would be your rockers. Those older style rockers, and even a lot of aftermarket rockers on LS based will cause this to happen. Sorry, I didn't notice it was SB based till after my post. You should be able to reduce sensitivity on them.

  10. #10
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    Ok my rockers are Comp cam Pro 1.6 this is a LT1 383. My PCM is out of 2000 Silverado
    Last edited by 540gts; 06-13-2014 at 03:32 PM.