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      03-13-2020, 12:08 AM   #26
Nezil
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Drives: LCI '18 6MT M2
Join Date: Jul 2017
Location: San Francisco Bay Area

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I did some further testing today to see if the waste gate delay was caused by the DME seeing the clutch position, or due to simply getting back on the gas from a 1 second lift off. To do this I conducted 2 tests:
  1. A 'no lift shift' from second to third: https://www.bootmod3.net/log?id=5e6a...0b4350057969b9
  2. Going from floored in gear, to lifting off for 1 second (no clutch) to floored again: https://www.bootmod3.net/log?id=5e6a...0b4350057969bd
Both of these cases resulted in no waste gate drop when back on the gas!

The second test was quite informative because it does show the same boost drop when you lift, but has different characteristics when you floor it again. Wastegate is pegged at 100% from only 62% pedal position and stays there until the boost target is met... as I would expect.


The 'no lift shift' felt pretty terrible; a big shock to the drivetrain, and I don't think I'll be doing that again in a hurry. Boost was held through the shift, so the waste gate never had to close, so I'm not sure how useful this test was.

The next test I plan to do is shifting up without the clutch. This is slower than with the clutch, because you have to wait for the revs to drop to match the gearbox speed, but it is pretty easy to do on an upshift. This should indicate if it's the clutch signal to the DME that is causing the waste gate delay because it doesn't seem to be present when you simply let off the gas.
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2018 ///M2 LCI, LBB, 6MT...

Current Performance Mods:
CSF FMIC, ER CP, Fabspeed Cat, Aquamist WMI, GFB DV+, NGK 97506, BM3 (Stage 2 93 OTS), CDV delete, UCP, M2C/M3/M4 Strut Brace, M3/M4 Reinforcement Rings
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