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Thread: Not atkinson cycle engine

  1. #41
    Senior Tuner Higgs Boson's Avatar
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    Quote Originally Posted by murfie View Post
    What is the weak link if it wasn't the exhaust?
    Intake manifold I guess.....considering how much the gt350 IM is picking up....more than long tubes......

    I put one on my car and it's noticeable.

  2. #42
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    Quote Originally Posted by Higgs Boson View Post
    Intake manifold I guess.....considering how much the gt350 IM is picking up....more than long tubes......

    I put one on my car and it's noticeable.
    I see them pickup up top but low and mid not so much. Your saying partial throttle it picks up a noticeable amount.

  3. #43
    Senior Tuner Higgs Boson's Avatar
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    Quote Originally Posted by murfie View Post
    I see them pickup up top but low and mid not so much. Your saying partial throttle it picks up a noticeable amount.
    It feels great at part throttle, which is not reflected on a wot dyno pull. I don't have any numbers on it. Definitely nothing lost anywhere and a huge bump up top.

  4. #44
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    I'm can think of two solid benefits to doing the intake/tb rather than headers. Not having to chase false knock from clearance issues and not having to worry are the neighbors going to slash my tires from the noise my car makes. If the power benefits are the same or even more intake had to be the smart choice. Ideally you want both because racecar.

  5. #45
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    Quote Originally Posted by Higgs Boson View Post
    It feels great at part throttle, which is not reflected on a wot dyno pull. I don't have any numbers on it. Definitely nothing lost anywhere and a huge bump up top.
    I haven't changed my cylair tables or disabled airman logic. What do each of those do?

    How was it tuning the gt350 manifold and wot and partial throttle?

  6. #46
    Senior Tuner Higgs Boson's Avatar
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    We have a thread on them but I am still not completely sure what they do. I have them both Enabled at the moment as the car would not idle with one or both disabled. I can say that disabling CylAir Filter will not allow the car to even run, lol.

    One or both of them have to do with using the VE tables but I don't know how to edit them without some kind of tool, like Bluecat or the GMVE Editor we have for GM stuff. It's kind of killing me because I always tune the VE and I can't on this one and it makes such a massive difference in how the car runs.

  7. #47
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    briefly clyair is a multiplier to the final volume of air in the cylinder value the MAF sensor and math calculations gives you. Desired air mass is the speed density tables so all values are based on prediction models and math formulas.

    I would start with the multiplier and raise that up. The stock desired air mass seems to be able to handle being off quite a bit because of the Clyair multipliers.

  8. #48
    Senior Tuner Higgs Boson's Avatar
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    What is the point of the CylAir Mult? Why doesn't the tune just measure and use the real numbers as they actually are?

    What is the effect of raising CylAMult? Why not just make it "2?" Why not just make it "1?"

    If the max Air Load at WOT in the SD tab says, let's say, 5000 RPM is .95 Air Load but in my logs I am getting .78 is this because the CylAirMult is too low? What are the effects of having the Max Air Load at WOT be correct or wrong?

    etc

  9. #49
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    All it's for is when the speed density is a bit off. setting them to 2 will just increase the effect if it needs it.

    If you want to disable the cylair anticipation that shuts off the speed density cross check and it just goes purely on MAF values. OR leave it on and use the multipliers to soak up any error in the calculations.
    Last edited by murfie; 02-04-2016 at 12:22 PM.

  10. #50
    Senior Tuner Higgs Boson's Avatar
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    I just bumped my cyl ant from 1.05 to 1.2 and it completely smoothed out any remaining part throttle buck or surge with SD enabled. Car is running better than ever now. Pretty cool.

    Will check any effect on max air loads.

  11. #51
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    My car has a weird buck during warm up around 2500rpm. Is that the buck you experience?

    Kris

  12. #52
    Senior Tuner Higgs Boson's Avatar
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    That sounds like a TM surge. I was getting what felt like a lean buck.

  13. #53
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    I run my car at 2 on both multipliers. No issues at all. It could be the cause of it not going into deceleration fuel cut off. But that would be the only issue I see.

  14. #54
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    Quote Originally Posted by Higgs Boson View Post
    That sounds like a TM surge. I was getting what felt like a lean buck.
    What is a TM surge?

  15. #55
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    Torque management or throttle mapping?

  16. #56
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    torque management is what i meant. what have you changed with your torque model? Torque/Inverse? Driver Demand? what did you change with your GT350 intake / throttle body config?

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    I've changed nothing at partial throttle with driver demand and torque inverse.

    I'm still running the stock manifold and throttle body. I thought you had a gt350 manifold.

  18. #58
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    Quote Originally Posted by kris5597 View Post
    I've changed nothing at partial throttle with driver demand and torque inverse.

    I'm still running the stock manifold and throttle body. I thought you had a gt350 manifold.
    I do, I thought you bought one also.

  19. #59
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    Quote Originally Posted by Higgs Boson View Post
    I do, I thought you bought one also.
    Ah, no sir, not just yet. That is my next purchase. How it VCT tuning on that at partial throttle and WOT? What does your VCT look like?

    Kris

  20. #60
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    Quote Originally Posted by kris5597 View Post
    Ah, no sir, not just yet. That is my next purchase. How it VCT tuning on that at partial throttle and WOT? What does your VCT look like?

    Kris
    Stock at part throttle right now and similar to what you did at WOT. I have not optimized it for the intake manifold.

    I've probably flashed the car about 300 times by now with all kinds of "experiments...." Will update you how raising CylAirMult affects latitude changing cam events at part throttle.