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  1. #26
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    Click here to enlarge Originally Posted by Carl Morris Click here to enlarge
    The problem that bothers me the most is that the boost target is being lowered by something beyond my control to something less than what is required to hit the load target. I am hitting my boost target from 4000-5500rpm but that still leaves me at 20-30 under my load target. I've gotten nowhere with Cobb when I ask them why and how I can get control of whatever de-rating is going on. Right now I'm just using the Stage1+ load target map since I can't hit the target anyway if it's set above about 150-160.

    But anyway, I don't know if you've seen the logs I posted on the other board ATR thread lately, but other than not getting enough boost to hit load targets I am happy with how the above maps are functioning. It puts me about 1psi closer to the boost target above 5500rpm than I was when I was using unmodified WGDC maps.

    One thing that I'm not understanding yet is if I reduce the target load down to what I'm actually achieving I seem to get odd behavior. Like some sort of overboost error condition that drops the timing to about 0 degrees until the ECU thinks it's under control again at about 5000rpm (this is with no knock retard recorded). So I've left it set at 186 even though I only hit 150-160 or so. All of this may be unique to high elevation use.

    I suspect that part of the answer might lie in the WGDC I table. I haven't seen anyone adjust this table, but the I factor in PID tuning is what helps with steady state error and accumulation of error over time which is essentially the state that you are at by the time you have pulled up to higher RPMs. Upping the I values should help the PID pull the WGDC towards making the boost targets.

  2. #27
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    At high elevation where I am I can max the WGDC out at 57% above 5500rpm and fall more than 2psi away from the target. The turbos are just too small to do what I'm asking them to do even with the wastegate closed.

    My primary concern on this thread is why the boost target is so far below what it needs to be to hit the load target and why I can't seem to control that. Only Cobb knows the answer...

  3. #28
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    Click here to enlarge Originally Posted by Carl Morris Click here to enlarge
    My primary concern on this thread is why the boost target is so far below what it needs to be to hit the load target and why I can't seem to control that. Only Cobb knows the answer...
    This may have to do with the boost limit, which is likely more than its label.

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    Click here to enlarge Originally Posted by GoodToGo Click here to enlarge
    I suspect that part of the answer might lie in the WGDC I table. I haven't seen anyone adjust this table, but the I factor in PID tuning is what helps with steady state error and accumulation of error over time which is essentially the state that you are at by the time you have pulled up to higher RPMs. Upping the I values should help the PID pull the WGDC towards making the boost targets.
    A PID thread would be good.

  5. #30
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    Click here to enlarge Originally Posted by JoshBoody Click here to enlarge
    This may have to do with the boost limit, which is likely more than its label.
    @Carl Morris If you are not hitting 18.6 psi, you need to tweak load target + base WGDC + WGDC limit to get more boost. Not a fun process but it's a one-time thing. Also, the 57% WGDC limit is there for a reason.

    The v402 PID is so good that I don't feel it needs any adjustment. Even with my super-tight RB turbo wastegates, they seem to respond well to minimal base WGDC adjustment and buttery smoothness. I can happily hit 18 psi tapering to 16 at redline with very few adjustments.

  6. #31
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    Click here to enlarge Originally Posted by themyst Click here to enlarge
    @Carl Morris If you are not hitting 18.6 psi, you need to tweak load target + base WGDC + WGDC limit to get more boost. Not a fun process but it's a one-time thing. Also, the 57% WGDC limit is there for a reason.

    The v402 PID is so good that I don't feel it needs any adjustment. Even with my super-tight RB turbo wastegates, they seem to respond well to minimal base WGDC adjustment and buttery smoothness. I can happily hit 18 psi tapering to 16 at redline with very few adjustments.
    What about if you want more than 16psi up top? Any issues with that?
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    Click here to enlarge Originally Posted by themyst Click here to enlarge
    @Carl Morris If you are not hitting 18.6 psi, you need to tweak load target + base WGDC + WGDC limit to get more boost. Not a fun process but it's a one-time thing. Also, the 57% WGDC limit is there for a reason.
    I'm not sure you're understanding what happens at high elevation. I think Cobb is intentionally (or hasn't found a way to control yet) derating the boost target due to lower ambient atmospheric pressure. It doesn't matter how high you set the load target. The boost target stays down between 15-16psi in hot weather and now that it's cooled off appears to rise to 16-17psi in the cold weather. That puts the load at 150-160 in the hot weather and 160-170 in the cold weather. No matter how high you set the load target, the boost target is kept too low to exceed those load numbers. And I had to zero out the pressure drop across the IC table just to get the boost target that high.

    Then there's the whole issue with the turbos not being big enough to hit the boost target above 5000rpm or so even at 57% WGDC after PID, but that's a separate problem.

  8. #33
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    Click here to enlarge Originally Posted by Carl Morris Click here to enlarge
    I'm not sure you're understanding what happens at high elevation. I think Cobb is intentionally (or hasn't found a way to control yet) derating the boost target due to lower ambient atmospheric pressure. It doesn't matter how high you set the load target. The boost target stays down between 15-16psi in hot weather and now that it's cooled off appears to rise to 16-17psi in the cold weather. That puts the load at 150-160 in the hot weather and 160-170 in the cold weather. No matter how high you set the load target, the boost target is kept too low to exceed those load numbers. And I had to zero out the pressure drop across the IC table just to get the boost target that high.

    Then there's the whole issue with the turbos not being big enough to hit the boost target above 5000rpm or so even at 57% WGDC after PID, but that's a separate problem.
    You're maxing out the turbos at elevation. I can only offer my insight at 100 feet below sea level, sorry I missed that you were at elevation. There's nothing you can really do to make those suckers flow then.

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    Click here to enlarge Originally Posted by rader1 Click here to enlarge
    What about if you want more than 16psi up top? Any issues with that?
    Not with my turbos, but with stockers probably going to be real difficult without running a ton of WGDC.

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    Click here to enlarge Originally Posted by themyst Click here to enlarge
    Not with my turbos, but with stockers probably going to be real difficult without running a ton of WGDC.
    What i wanted to hearClick here to enlarge
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    Click here to enlarge Originally Posted by themyst Click here to enlarge
    Not with my turbos, but with stockers probably going to be real difficult without running a ton of WGDC.
    Why not with your turbos? Stiff Wastegates?
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  12. #37
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    Click here to enlarge Originally Posted by marv85 Click here to enlarge
    Why not with your turbos? Stiff Wastegates?
    Bigger turbos will be able to hold boost better because they can move a greater volume of air. Smaller turbos will have to work a lot harder to sustain the same boost curve(IE more WGDC)
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  13. #38
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    Click here to enlarge Originally Posted by rader1 Click here to enlarge
    Bigger turbos will be able to hold boost better because they can move a greater volume of air. Smaller turbos will have to work a lot harder to sustain the same boost curve(IE more WGDC)
    Hey man Click here to enlarge

    yeah I know that part, but I was asking why can't his Turbos hold more than 16psi up top? I mean he has RBs
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    Click here to enlarge Originally Posted by marv85 Click here to enlarge
    Hey man Click here to enlarge

    yeah I know that part, but I was asking why can't his Turbos hold more than 16psi up top? I mean he has RBs
    The way I interpreted what Myst said was that HIS turbos would have no problem holding boost but the stockers would have a problem.
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    Click here to enlarge Originally Posted by rader1 Click here to enlarge
    The way I interpreted what Myst said was that HIS turbos would have no problem holding boost but the stockers would have a problem.
    I reread what he wrote and yes you're right... I thought he was saying the opposite so I got confused...

    I have high hopes for your Stage 2 upgrade. Fingers crossed.
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  16. #41
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    Click here to enlarge Originally Posted by marv85 Click here to enlarge
    I reread what he wrote and yes you're right... I thought he was saying the opposite so I got confused...

    I have high hopes for your Stage 2 upgrade. Fingers crossed.
    Same here haha
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    What does Boost Setpoint Factor (Factor) depend on? with respect to ATR tables / workflow? I'm not seeing anything that determines it?

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    Click here to enlarge Originally Posted by bv1 Click here to enlarge
    What does Boost Setpoint Factor (Factor) depend on? with respect to ATR tables / workflow? I'm not seeing anything that determines it?
    bump @dzenno@ProTUNING Freaks

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