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Thread: boost control

  1. #21
    Advanced Tuner
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    It forces your wastegate solenoid dutycycle to be no less than 80%, so it?s forcing it to stay more closed or in other words not allowing it to open as much.

  2. #22
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    With min wastegate solenoid duty cycle back down to 0% your desired estimated airflow tables should work properly to control the wastegate solenoid.

  3. #23
    gocha, so if I have the minimum duty set to 80 percent it could only open the wastegate a max of 20 percent open?

  4. #24
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    More or less, yes

  5. #25
    thanks for the help, now I have a better idea of what stuff does

  6. #26
    Potential Tuner
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    Oct 2019
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    Quote Originally Posted by JaegerWrenching View Post
    40 PSI is at seal level and 40 psi at elevation are two different things. If our starting absolute is 11.9PSI at elevation 51.9psi absolute would be 40 psi above it. But at sea level if our starting was 14.7 obviously we'd have 54.7psi absolute. This is why trucks and cars make more or less boost on the same static waste-gate settings when changing elevation. A 10lbs waste-gate spring will open when it reaches that threshold, but as we change elevation atmospheric pressure on the backside of the waste-gate changes as well. So you will make the atmospheric difference in boost pressure with the same waste-gate spring on the same setting. This only truly matters if you're goal is X amount of absolute boost or X amount of Actual HP. You will have to spin the turbo faster at elevation to produce equivalent power. It may start pushing your turbo outside it's efficiency range or compressor island, producing more heat than the added boost is worth.
    Thank you for explanation, very clear

  7. #27
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    In my experience less timing will help get turbo going then add fuel then add your timing I don?t know how Cummings run but stock my Powerstroke timing map has -1.75 degrees you can also use post injection and split pilot not that I know how but i read it in a hot rod magazine

  8. #28
    Advanced Tuner
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    5.9 doesn?t have split pilot but you can use pilot and main to create a split injection event, I wouldn?t bother with that though. Reduced timing can be used to help aid spool but as mentioned elsewhere, the Cummins does like timing to get aggressive quick.