04-23-2024, 01:39 AM | #1 |
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Hi!
I’m chasing an issue where the car overboosting right after going from 4>5 gear. I could feel it in the car when throttle closes and DV dumps slightly. The car will jolt I have smoke tested with pressure multiple times and could not for my life find any leaks. It was leaking at intake connection down at the turbo but it is fixed! Watergate position is also checked with Ista and it shows no issues No codes no nothing. Log: https://datazap.me/u/lucasborka/over...og=0&data=3-21 https://datazap.me/u/lucasborka/clos...ata=3-17-21-24 Hot idle log: https://datazap.me/u/lucasborka/hot-...og=0&data=3-21 BMW 435i FBO 2015 Catless FMIC 5” CP Gfb DV+ without additional spring MHD Stage 2+ XHP stage 3 |
04-24-2024, 08:16 PM | #2 |
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Ironically i think that just happens sometimes when you have really good boost control. Here's some examples from my logs:
https://datazap.me/u/thejeremyman9/1...&data=4-5-7-17 https://datazap.me/u/thejeremyman9/d...=4-5-7-9-17-19 I think its happened less since i went down to XHP stage 2 but i havent logged 4-5 gear shift in a while. |
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04-25-2024, 01:20 AM | #3 | |
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But did you ever feel the closure? I can clearly hear the DV dump and the car jolts. If I go back to XHP stage 2 I never feels it |
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04-25-2024, 04:52 AM | #5 |
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04-25-2024, 11:44 AM | #7 | |
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I have only tried in manual mode and it doesn’t change gear. I’ll have to try in regular S mode Super wierd issue |
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04-25-2024, 04:55 PM | #8 | |
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MHD is very sensitive to overboost and quick to react if boost mani exceeds target (and relatedly if load exceeds target). Basically i think what is happening is when your boost control is so close to target and you shift quickly into a higher gear with more, the higher load pushes the boost over target right after the higher gear engages and what you feel/see in the logs is the reaction to the overboost. |
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04-25-2024, 04:56 PM | #9 |
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It doesn't really "dump boost" fully or anything, it just reacts to boost exceeding target my partially closing throttle and regulating the boost with the DV until you are back below target. But its not like its going back to zero boost then building back up, its more of a boost/load 'correction'
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04-25-2024, 11:57 PM | #10 | |
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Maybe I could benefit for a custom tune to eliminate this at stage 3 XHP. But I don’t want all the hassle 😂 I’ll have to accept that there is no issues with the car |
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