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Thread: Cruising NB #'s

  1. #1
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    Cruising NB #'s

    Can someone explain why my LTFT's are all -3 to -4, but I'm see 400's while cruising?

    Is 41 degrees too much at 70-75 mph or can I go higher and get more mpg?

    Thanks
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  2. #2

    Economy

    How did you manage to get 41* timing - mine is still capped at 40* and I cannot figure it out. At lowish cylinder loads (0.20-0.30g/cyl) I am told and read out of various techno/nerd books (cant try it for myself) an AFR of 16.0ish and 42* timing is ideal for LS1 economy. For me after many trials 40* (MAX) and 16.5 (Aussie LS1 lean cruise) gives the best economy upto 32 imperial MPG average on a reasonably flat road at an avg of 55mph (not sure what that is in US MPG)

    Also at low loads I would aim for trims of +1 or +2 upto +4 in decel(although I disabled LTFTs a while back) One of the Super Moderators (soundengineer or EC Tune, I cant remember which, sorry ) suggested this and it helps economy significantly.

    Ref the LTFTs what are your switchpoints at - if set less than what you are seeing than this could be a factor - not sure

    Good luck

  3. #3
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    Not to take away from my original question above, but, we both have reciprocal problems. With an American LS2 I can't lean it out, and it appears you are capped at 40*. Honestly, I'm not sure what you would really gain by going higher. I think its all coming from the AFR which I can't touch... yet?

    Now, why am I seeing 400's while cruising?
    www.outlawpontiacdragseries.com
    Come race with us in MA, PA, and VA!

    2005 GTO A4 - Spintech X-pipe with Powerstick mufflers, IAT relocate, Volant, !scoops, !cowlgasket, !skid plate, LM-1, HPT2.0/MPVI Pro USB, 275x40x17 Nitto DR, rolled fenders, Pedders 2985 springs, Britax baby seat with 5 point harness.
    Stock:13.36@104
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  4. #4
    Tuning Addict WS6FirebirdTA00's Avatar
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    what airflow mode are you in and what is the switch point in that airflow mode?
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  5. #5
    Супер Модератор EC_Tune's Avatar
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    LS2 -- no switchpoints. No Mode vs Airflow either. Request??!!??

    Not sure why SS is capped but PP can try a bit more SA if the LS2 will allow it.
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  6. #6
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    EC, what do you mean by SA?

    EC, is it normal to see 400's on the NB while cruising?
    www.outlawpontiacdragseries.com
    Come race with us in MA, PA, and VA!

    2005 GTO A4 - Spintech X-pipe with Powerstick mufflers, IAT relocate, Volant, !scoops, !cowlgasket, !skid plate, LM-1, HPT2.0/MPVI Pro USB, 275x40x17 Nitto DR, rolled fenders, Pedders 2985 springs, Britax baby seat with 5 point harness.
    Stock:13.36@104
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  7. #7
    Супер Модератор EC_Tune's Avatar
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    Spark Advance.

    the narrowbands should be tripping back & forth over 451 mv (o2 trip points in an LS2) They shouldn't be hovering totally in the 400 mv range AFAIK. If so you have an extremely tight loop control and should congradulate your self on some extra fine tuning!
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  8. #8
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    Well as you can see from the image attached, the average of each cell is hovering around 450's. I do see it swing from 50-900 back and forth which you can see on the bottom. So your saying its normal? Why do they do that, then jump to 890-910 when in PE?

    I'm far from congratulating myself. This has been really frustrating. I'm hoping Autotune and/or RTT for LS2's is coming.
    www.outlawpontiacdragseries.com
    Come race with us in MA, PA, and VA!

    2005 GTO A4 - Spintech X-pipe with Powerstick mufflers, IAT relocate, Volant, !scoops, !cowlgasket, !skid plate, LM-1, HPT2.0/MPVI Pro USB, 275x40x17 Nitto DR, rolled fenders, Pedders 2985 springs, Britax baby seat with 5 point harness.
    Stock:13.36@104
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  9. #9
    Супер Модератор EC_Tune's Avatar
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    The average should hover around 450mv as that is the trip point for rich/lean determination. If the average is moving up, you are rich, if down then lean.

    Have you tried turning off the LTFT's and tuning with just STFT's? Tightens up the VE table a bunch!
    Wish there were more loop controls in the LS2 like the LS1. Maybe in the next release....

    EC
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