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Thread: LT1 24x H/C/I Procharged

  1. #1
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    LT1 24x H/C/I Procharged

    KInda just seeing how things are going, looking for advice and critiques.

    Car is a gen 2 LT1 24x of course. Pro charger 14.5psi. TFS 180 ported heads, 223/235 114 cam, mostly forged but wasnt originally boost built and 11 to 1 compression.
    4l80e w/3600 protorque converter and s60 rear.

    Tuning in speed density, open loop on 93 with an ethanol content reading of 9-10% as to why the command shows what it shows. Yes i have an ethanol sensor and will be running Flex/E85 as soon as i get the AFR in a smudge more. Prob will need injectors tho.

    She has a slight lean on tip in and light throttle which is where the red areas come in it seems. I believe a few knock events are false. Knock detection on these 24x swapped cars seem random.

    Im hitting 14.5psi which seems like a lot for the pulley at 3.7. Low end seems great top end is meh. She seems a bit low on power for what it is thats partly why im looking for another set of eyes to look at the logs/tune. IAT seem to roll in fast in third.

    Thank you

    23-08-20 16-56-49.hpl

    VE-Timing-Boost AFR LT1T ver 02 Conversion to OL_REV 7BD.hpt
    1997 30th SS. Torqhead 24x, TFS heads, 223/235 cam, 4l80e, S60 D1SC 14psi

  2. #2
    Senior Tuner edcmat-l1's Avatar
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    How can definitely take a little bit of WOT fuel out of it and the old small blocks all like more timing even at 11:1 compression. Up top where you've ramped it down you can probably some back.

    What intake manifold?

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  3. #3
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    Quote Originally Posted by edcmat-l1 View Post
    How can definitely take a little bit of WOT fuel out of it and the old small blocks all like more timing even at 11:1 compression. Up top where you've ramped it down you can probably some back.

    What intake manifold?
    I just ran 20 degrees up top and showed 1 - 1.6 degrees of knock but I could probably go for another hit and not show any.

    Right now my WOT fueling is set to 11.48 but the 9% ethanol reading brings it to about 11.04. are you saying I can lean it out more than 11.48?
    I'm just getting comfortable with it.
    1997 30th SS. Torqhead 24x, TFS heads, 223/235 cam, 4l80e, S60 D1SC 14psi

  4. #4
    Senior Tuner edcmat-l1's Avatar
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    Quote Originally Posted by anniversaryss View Post
    I just ran 20 degrees up top and showed 1 - 1.6 degrees of knock but I could probably go for another hit and not show any.

    Right now my WOT fueling is set to 11.48 but the 9% ethanol reading brings it to about 11.04. are you saying I can lean it out more than 11.48?
    I'm just getting comfortable with it.
    I's shoot for mid 11s to about 11.7.

    In something like that, gen 3 PCM on a small block, I would not be looking at knock retard unless you've set them up using a knock headset. Gen 3 PCMs were notoriously undependable for accurate knock detection to begin with.

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    Absolutely!! I had a feeling you'd say something similar to that. The knock detection coming from the pcm tends to be random and sometimes I get it, sometimes I don't. As I said i could go for another run and the knock won't be there.
    1997 30th SS. Torqhead 24x, TFS heads, 223/235 cam, 4l80e, S60 D1SC 14psi

  6. #6
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    I agree on a lot of points.

    Timing seems low.. need a dyno and some plug readings to verify
    Fuel seems rich. high 11's perfectly OK
    and knock detection isn't reliable especially on 24x swaps. I don't honestly know if I seen one yet behave like I'd expect.
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  7. #7
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    Quote Originally Posted by Alvin View Post
    I agree on a lot of points.

    Timing seems low.. need a dyno and some plug readings to verify
    Fuel seems rich. high 11's perfectly OK
    and knock detection isn't reliable especially on 24x swaps. I don't honestly know if I seen one yet behave like I'd expect.
    I agree. I'm working my way in there. I def have to do some plug reads.
    I think we talked in another post I made about knock sensors and I planned on swapping to the ks7 sensor to test. Still seems random and not dependable.
    I'll keep at it and take some pointers from you guys.
    1997 30th SS. Torqhead 24x, TFS heads, 223/235 cam, 4l80e, S60 D1SC 14psi

  8. #8
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    Quote Originally Posted by anniversaryss View Post
    I agree. I'm working my way in there. I def have to do some plug reads.
    I think we talked in another post I made about knock sensors and I planned on swapping to the ks7 sensor to test. Still seems random and not dependable.
    I'll keep at it and take some pointers from you guys.
    I've tried knock sensors out of this or that.. still haven't seen them act in a way I would expect. I came from LT1 tuning.. chip LT1 tuning in fact.. The LT1 ECM/PCM's definitely reported knock normally like a newer car.. You could build a timing map easily with where it is knocking and where it is not. I've not seen one LT1, BBC, or SBC 24x swap do the same.

    From school I know knock sensors have to be tuned for the bore size they are used in and there needs to be some function on what the speed of sound is inside the bore, at temperature, with the density of the mixture, etc. Its not as simple as listen for a bang. I think this stuff is likely inside the calibration where we can't see and wouldn't know exactly what to change anyway.
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