Is it my turbo? wastegate? or something else.

Discussion in 'Mazdaspeed 3 General Discussion' started by Matt Dickey, Nov 11, 2021.

Watchers:
4 users.
  1. Matt Dickey

    Matt Dickey Greenie Member

    Joined:
    Apr 3, 2021
    Posts:
    64
    Trophy Points:
    8
    Location:
    California
    Ratings:
    +8 / -0
    okay so this might get long winded but in short im hyper conscious of the health of my engine and im noticing things in my logs while re tuning for a different setup that dont make sense to me and im just looking for clarification and making speculation based on research that i have done myself.

    recently i added an XS power exhaust manifold, COBB sf intake and turbo inlet pipe with the largest K&N filter i can fit into the available space, vtcs delete and IM polish, and a COBB front mount intercooler.

    previous setup unchanged mods include, hpfp internals, egr delete, 3" catless turbo back, CS 3 port BCS, bosch 3 bar map sensor with adapter.

    the previous setup was CS tmic, stock exhaust mani, and ebay TIP with SURE motorsports short ram with slightly smaller air filter and other mods listed above as previous.

    however looking at the current logs for the tune im working on with will from PDtuning it seems my WGDC is almost 30% higher at the same given RPM and very close to similar boost pressure, and in cooler weather and the intake which SHOULD be more efficient, given the ID of every part until the turbo connection is bigger in diameter thus should support more flow, is reading less G/S from the MAF (i suspect this is because the maf was very dirty and i have cleaned it last night and not logged since) and it seems like the car is struggling to reach the 22 psi set max boost for the tune and is only holding to 15psi around 6k and showing 65% up to 100% WGDC whereas the previous tune would hold 21 psi easily and hold out to 17psi at 6k with less than 60% WGDC. i found the exhaust manifold to turbo gasket severely leaking so i replaced it and the DP gasket to eliminate that as a cause and it still seems the wgdc is still much higher than it was previously but i noticed that the exhaust manifold was leaking hot exhaust gas directly at the wastegate actuator the houses the spring and diaphragm and further research showed that when exposed to high temperatures springs will soften and become weaker over time.

    so my speculations are wgdc was increased by both the pre turbo exhaust leak and the wastegate actuator spring being cooked and loosing its integrity causing the EBCS to need to input more Duty cycle to keep the wastegate closed. or the turbo is showing age and starting to loose efficiency, however the car almost never sees WOT other than tuning pulls i drive the car very tame 97% of the time there is no abnormal ammount of shaft play and the turbo does not smoke. so im reluctant to believe the turbo is failing but i am willing to entertain the possibility.

    my questions are, would anything else i listed or am unaware of cause this WGDC increase and boost curve decrease? do you think there is any merit to my speculation about the leak and WG spring loosing integrity and why/why not. and do you see anything in the logs that might help support this or disprove it. i have a low mile KO4 i dissected to rebuild that i can take the wastegate actuator off to swap to the new turbo to see if this could be the cause for scientific purposes and will update when i do.
     

    Attached Files:

  2. L337TurboZ

    L337TurboZ World Class Truck Squatter Greenie Member

    Joined:
    Jun 15, 2020
    Posts:
    1,132
    Trophy Points:
    113
    Location:
    Charleston, SC
    Ratings:
    +1,149 / -4
    Are you running the stock turbo? If so it isn't going to hold more than 17psi near redline. They can shoot up quick to 22 psi but immediately begin to fall off as they aren't large enough
     
    L337TurboZ, via a Motorola device, Nov 11, 2021
    #2
  3. Enki

    Enki Motorhead Platinum Member

    Joined:
    Feb 10, 2016
    Posts:
    2,244
    Trophy Points:
    113
    Location:
    Tucson
    Ratings:
    +3,236 / -3
    I used my settings for both of these, so while the power is probably wrong it doesn't matter.

    upload_2021-11-14_1-4-41.png
     
  4. Matt Dickey

    Matt Dickey Greenie Member

    Joined:
    Apr 3, 2021
    Posts:
    64
    Trophy Points:
    8
    Location:
    California
    Ratings:
    +8 / -0
    okay i replaced the turbo with a rebuilt one and here is the datalogs from the new turbo
     

    Attached Files:

Loading...

Share This Page

Users Viewing Thread (Users: 0, Guests: 0)