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boost pressure drop during run

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Old Aug 15, 2017 | 08:00 AM
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Default boost pressure drop during run
I have a 5.3 th400 with a 78/75 on3 turbo and with it set at 13 lbs it holds there during first and second gear but during third gear it drops to 9 lbs. What are things to consider for this. Other car I did with a glide held same pressure from start to finish. All help appreciated as I must be overlooking something.
Thanks in advance
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Old Aug 16, 2017 | 06:26 AM
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As a starter>>>data logging?
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Old Aug 16, 2017 | 07:42 AM
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What ecu, wastegate, boost controller? Where is the wastegate placed?
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Old Aug 16, 2017 | 08:33 AM
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Originally Posted by svslow
What ecu, wastegate, boost controller? Where is the wastegate placed?
Microsquirt, 50mm that I have checked for problems and no leaks, turbosmart dual stage controller inside with hardlines to it. Wastegate is set on 45 angle just prior to turbo on merge to T4 flange. Also checked charge pipe for leaks and there are none there.
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Old Aug 16, 2017 | 08:35 AM
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Originally Posted by Old Geezer
As a starter>>>data logging?
Will try to get datalog for you but I havent seen anything there that is wrong in my eyes
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Old Aug 16, 2017 | 11:05 AM
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What does it do with no boost controller hooked up?
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Old Aug 16, 2017 | 11:46 AM
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going to do that next as I think the signal is slow to recover after going that far, But what do i know lol
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Old Aug 16, 2017 | 11:52 AM
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