Tuning for CST4 turbo

Discussion in 'Mazdaspeed 3/6 ECU Tuning' started by Shadowplane676, Feb 19, 2020.

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  1. Shadowplane676

    Shadowplane676 Greenie Member

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    So I did find that there were three additional tables that are the ones mainly affecting AFR on full throttle. They were specific single row tables for WOT conditions. I adjusted those to mimic what I was targeting in the primary 3D tables and was able to see a change in logged AFR.

    I was able to log about 5-6 WOT pulls and saw at most 2.5 KR (with the corresponding change in AFR as the ECU flipped from base WOT AFR targets to the Knock AFR targets). Generally my knock was quite contained, however the odd higher knock was as best as I can determine, a byproduct of heat soak/increased BATs into the 150* or higher range due to heat soak.

    Additionally, cruising state still saw BATs around 100-110*. While the TMIIC may be ok for staving off obscene BATs, to me this is highlighting the fact that a FMIC is probably a good idea. an increased surface area intercooler along with better airflow for heat transfer hopefully will keep BATs down into a more agreeable range.

    Lastly, I did try and bump the WGDC and target boost by a small bit to test if I was in the right tables, but did not see a corresponding change in WOT boost logged yet.
     
  2. broda

    broda Silver Member

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    If you're hitting load limits per gear then increasing boost targets won't effect anything. The only way you'll hit the increased boost target at that point is if you reduce timing without changing load targets.
     
    Last edited: May 31, 2021
    broda, via a mobile device, May 31, 2021
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  3. Shadowplane676

    Shadowplane676 Greenie Member

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    That's the odd thing, current load by gear tables are significantly below the desired boost table and logged pressure. I.e. in 4th, i see peak boost of 2.09 bar, yet both load by gear tables peak at less than 1.7 bar.

    upload_2021-5-31_20-40-29.png
     
  4. broda

    broda Silver Member

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    Load and boost aren't the same thing. Load is essentially a calculation of your engine output based on various parameters. Boost is just your manifold pressure which is only a single factor in how much power your car is making.

    This is why load tuning is better than boost tuning. Say you've determined that 1.7 load is your max load value that you deem is safe before you starting getting knock. If the air is colder (therefore more dense = more oxygen), then you'll need less boost to hit the same load so you may only need 1.8 bar pressure to hit your same load target that requires 2.09 bar currently in hotter weather. For just a boost tune, if you're targeting 2.1 bar pressure your car is going to attempt to achieve that regardless of your ambient conditions so you may hit a 2.0 load on the same tune in colder weather.
     
  5. Shadowplane676

    Shadowplane676 Greenie Member

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    Fair enough and makes sense. What I am trying to do is be able to correlate what tables (whether boost or load based) are the ones that I need to edit to reach the tuning point I am aiming for.

    Looking at engine load, my log where I hit 2.08 bar of boost I logged a max engine load of 1.89 at the same point. Earlier that morning, I saw boost of 2.09, but load was only 1.72. Both data points are above the load by gear table values, and above the "desired boost load" table as well. This is where I am trying to clarify in my own understanding. I'd love to be able to just increase a desired load table and have the ECU work within the boost, WGDC, IAT, BAT and other limit tables to hit said load target, but i have yet to figure out which table or tables will do that yet.
     
  6. JohnnyTightlips

    JohnnyTightlips Platinum Member

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    https://www.versatuner.com/article/mazda-mzr-disi-23l-turbo-load-targeting-logic
    [​IMG]
     
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  7. Shadowplane676

    Shadowplane676 Greenie Member

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    @JohnnyTightlips - Thanks! That really helps with the thought process for the ECU. I did find a "Desired Boost Load" table, rather than a straight "desired Boost". Made some tweaks and saw some higher boost pressures and load values so continuing to slightly poke at things and see what happens.
     
  8. Shadowplane676

    Shadowplane676 Greenie Member

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    I am stumped. I have been trying to find which load/limit table is catching me out. I have adjusted a number of load tables mainly to the 2.10 to 2.20 range, but I cannot seem to exceed a load of 2. I have only peaked at 1.98 load on a cooler day. Otherwise I am consistently peaking at a load of 1.85-1.95.

    I have increased the fuel cut limit tables, load by gear, desired boost, desired boost load, target load, WGDC, overall load limits, load limit vs rpm, and per gear requested load limits. I feel like I am either missing a table in the ECU definition or overlooking a table relationship that is causing the ECU to select a lower load limit than the values I am trying to hit.

    I have looked over the flow chart a number of times, and one table I cannot seem to find is the APP load request. I am not sure if that is a name that is specific to VT, and as such, is called something else in ME. I am hoping I don't have to start learning Hex to go dig up undefined tables still in the ECU, but if that's what's needed...
     
  9. Shadowplane676

    Shadowplane676 Greenie Member

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    Eureka! Well, kinda. Ended up adjusting the boost compensation tables for 3,4 and 5-6 to 1 (vs having values as low as .8 in the main boost section). Definitely had more pep getting on the highway and saw boost up to 2.29 bar absolute. I did start hitting boost limit again so I am working on lowering some of my target values and upped the boost limiter a bit more. Load is still clocking in under 2, but at least I am now starting to see results when changing boost target, WGDC and other target values.

    Currently I have left gears 1 & 2 nerfed a bit until I get the target values sorted a bit more and better controlled.
     
  10. broda

    broda Silver Member

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    There's a lot of load tables that contribute to the max load allowable and the ECU will pick from the lowest one. I'm not sure what tables are called in VersaTuner vs MazdaEdit so I can't really spell them out lol.

    Would you be able to post a screenshot of the high load area of your timing table? Just curious what it is currently.
     
    Last edited: Jun 12, 2021 at 11:32 AM
    broda, via a mobile device, Jun 12, 2021 at 11:05 AM
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  11. Shadowplane676

    Shadowplane676 Greenie Member

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    Yeah, I wasnt 100% sure what boost comp was, but once leveled out to 1, it stopped nerfing my boost target values on gears 3-6.

    Here's my open loop max timing table
    upload_2021-6-12_11-30-8.png
     
  12. broda

    broda Silver Member

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    That's some weird ass timing. It should be a smooth increment up until redline. 10.5 @ 6500 RPM is pretty normal for now. Where it starts at 3.5 @ 2500 RPM 2.13 load you should probably do a +1 increment at (ie. 4.5, 5.5, etc.) until you hit 11.5 degrees @ 6500 RPM. 12.1 degrees is a ton of timing @ 4000 RPM which is probably where you'll see knock a lot.

    Then naturally you'll want to smooth it out for the map under it too.
     
    broda, via a mobile device, Jun 12, 2021 at 12:39 PM
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  13. Shadowplane676

    Shadowplane676 Greenie Member

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    I'm not surprised, there are a number of tables that looked odd when I got into the ECU. I have a suspicion someone else has been in the tune before, probably one of the reasons its on a replacement motor. Thanks for the info on the timing. Anything else I should be looking at?

    Fortunately I haven't seen much knock, usually below 2-2.5 with only one or two entries in the 3's

    I am considering getting the CS 4.5 BAR map sensor and BCS to help with tuning control and boost headroom.
     
  14. Shadowplane676

    Shadowplane676 Greenie Member

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    Something more like this for timing? Seems a bit smoother and reigned in on the higher load areas

    upload_2021-6-12_12-2-46.png
     
  15. broda

    broda Silver Member

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    That looks better. If you're constantly getting knock from your timing table being jacked up it'll be harder to tune since your ECU will be pulling timing and targeting lower loads. So then you won't really know where you're at. At least now it should be more consistent.

    I'd recommend a Bosch 3.5 BAR MAP sensor if you're going to upgrade. Love CS products but it seems like the MAP sensor is more issue prone.
     
    broda, via a mobile device, Jun 12, 2021 at 1:08 PM
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  16. Shadowplane676

    Shadowplane676 Greenie Member

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    Agreed, luckily i have not seen very much knock logged, even with IATs in the 150* range and WOT fuel backed out to 10ish under knock rather than 9:1. Another item on my soon to upgrade list is going FMIC with a mishimoto 3" intercooler I have from a previous project. The more I can keep the charge air temps down, the better power and longevity (i.e. less LSPI or regular knock) I should be able to get out of the car.
     
    Last edited: Jun 12, 2021 at 5:08 PM
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