Tuning for CST4 turbo

[Shadowplane676]

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.

 

[broda]

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.

 

[Shadowplane676]

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.

 

[broda]

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.

 

[Shadowplane676]

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.

 

[JohnnyTightlips]

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.

https://www.versatuner.com/article/mazda-mzr-disi-23l-turbo-load-targeting-logic

 

[Shadowplane676]

@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.

 

[Shadowplane676]

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...

 

[Shadowplane676]

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.

 

[broda]

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.

 

[Shadowplane676]

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

 

[broda]

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.

 

[Shadowplane676]

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.

 

[Shadowplane676]

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

 

[broda]

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.

 

[Shadowplane676]

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.

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.

 

[Shadowplane676]

and stuck again....

I think I have not been able to find the map limits or how to rescale some maps to shift the resolution. I.e. The relative throttle plate position A and absolute throttle plate position tables go off the right end of the map as I can exceed the last column of Engine Load = 2. If I could find the way to rescale or extend the map to cover higher loads I'd feel better. I suspect the ECU will use the last cell it knows or the last column in this case, but I'd prefer it to stay within the table..




Also, I think I am still getting nerfed somwhere. I suspect there's a load table (probably APP load request?) or other that is keeping things toned down. I am only seeing Accelerater Angle (main) maxing at ~67 to 70% and thus not allowing the ECU into the upper ends of some of the load tables. My Pedal to Plate mappings "should" allow 100% throttle opening, but something is mitigating that I think.

 

[Shadowplane676]

Back at it tuning the speed again. Lost our daily SUV to a deer so the Speed had to come back into daily use.

Chasing a stumble/cutout that I can't seem to narrow down. Only happens at low throttle and between 2000 and 3000 and acts like fuel cut. logs don't show any real knock, fuel drop out or other reason for the hard miss/stumble. it can happen once, or 2 to 3 times. letting off/clutching in or shifting down a gear generally sorts it out, but thats basically just moving the motor out of that area of the maps. I have lowered WGDC to pretty much 0 in this area so it shouldn't be boosting at all. Stock plugs are at about 25,000 miles.

Also, I have seen some references to programmed in "safeties" for the motor. I'm curious if these are just nerfed regions of the maps that essentially save the motor from abnormal conditions.

 

[Crazycanadian]

I was going to get more into all this info as I wrote out my build thread... but after reading your post I think there's some important information to pass on to help fill in some gaps...

First off, your current problem sounds like a possible ignition misfire from a bad ignition coil, or spark plug... I'd diagnose this before diving to far into tuning issues...

As for some of your previous struggles with load/boost limits..
For logging, you mentioned knowledge of ForScan... stop using VT to log... go use ForScan.. SOOO MUCH better... It's a little tricky to understand some of the EQ pids and which ones to use, but the logging rate is WAAAAY faster, much more comparable to what you're used to with a stand alone ECU... You can log more pids with out loosing resolution in your logging rates.. This might help you find some of these issues better.. If you are familiar with the scanner diagnostic functions, look up Mode 6 data and the misfire counters.. This will help you to diagnose the current possible misfire issue you've got... You can see individual cylinder misfire data, without a check engine light, or any codes.. You can use that data to narrow down which cylinder has the problem...

Carrying on...
"Load"... All of this load targeting and such... What you are targeting is air mass per intake stroke... You aren't targeting power, or a torque value... This is an air mass calculation.... If you want to go to town mathing your way to a tune, you can google the OBD2 information for Absolute Load... you'll get some formulas with that information.. All of the Fuel tables, and Spark tables will follow the absolute load readings you get from any scanner and what you've got in your tables... This is mandated by federal OBD2 regulations... Your Drive By Wire tables use a different air mass per intake stroke calculation that's more in depth and I can't find any information on it..

I've been told that the OEM coding, doesn't use the boost target table.. No clue what Mazda Edit would call that table, but it's RPM/TPS 0-100%.. with MAP values in it.. From what I understand Cobb is accessing/turning on the OEM development coding, that activates this boost target table as part of their boost targeting strategies.. I don't know what Mazda Edit would do with this table... I don't expect this to be where you were struggling with your previous load limit issues.. But if you choose to modify it, it's important to know that the TPS% value is based off a scanner pid call Relative TPS... this is a calculated TPS value.. The ECU runs a throttle body test every time you shut the car off.. It closes the the throttle blade as far as it can go, and then opens it as far as it can go... The ECU memorizes the TPS voltages at the closed position.. ForScan allows you to see this voltage value... it uses that voltage as the 0% mark for the relative TPS value... The DBW tables (at least 1 of them, you mentioned was labled as Relative TPS)... these values are used for the WG Duty Cycle Table TPS values... If you log Relative TPS and WG Duty cycle, you can map out your WG Duty cycle Table...

If you are hitting a load limit it'll be due to a couple different reasons... You'll have 3 APP target tables (0-100% and RPM), Both COBB and VT show a 4th APP target table, but I haven't seen it do anything with my tuning adventures.. the ECU attempts to target the lowest of these values anytime you aren't under WOT conditions... The load target per gear tables are used under WOT conditions... All of these tables you can over shoot your targets.. You're WG and Load compensation tables are used to try and keep you with in these targets.. You could be limited in this area...

You'll have 2 RPM based MAX LOAD tables (VT calls them Operating Load limits, COBB calls them Calc Load MAX)... these tables, set the max fueling calculation limits.. If you use ForScan for logging and you watch the Calculated Load pid.. You'll see this value change if you change these Operating Load Limit Tables... There's 1 more RPM based MAX LOAD table and a single value max load.. (VT calls it Requested Load Limit RPM, Requested Load Limit Overall.. COBB calls them Throttle Requested Load A/B)... These tables work the same as the Operating Load limit tables, but work on the DBW load calculations.. Then you have a BARO/RPM requested Load limit table.. These tables define max limits.. the ECU takes more extreme measures such as slowly cutting fuel in order to stay with in these limits... So you could be limited in that area.. especially if you find you've been adding fuel to your MAF cal in this area...

There's an RPM based soft boost limit table... VT calls it overboost protection throttle reduction, Cobb calls it Boost Threshold for Baro Multiplier... This table works in conjunction with a BARO/RPM Multiplier table.. VT calls this table boost limit baro adjustment.. It's show as values in % form... Cobb calls the table WG Duty baro multiplier.. They list it as a number value 1.0 - 0.5.. How it works is simple.. Stock value at 5500 RPM is 29.2 psi (this is an absolute MAP value from VT).. Cobb takes the absolute map and converts it to a gauge map value.. I don't like this.. it creates more work, if you're going to do any math work to develop your tune.. You should be tuning/logging in absolute map values... side note over... on the BARO/RPM table at 13.56psi and 5500RPM the value is 86.6%.... You take 29.2psi and multiply it by 86.6%... This equals 25.29psi... So if you've got a BARO reading 13.56psi, your map limit is 25.29psi (11.73 PSI boost pressure)... Stock values run 100% above 13.56 baro... So that means you'd be running at 29.2psi (14.49 boost pressure at 14.71 baro)... This is a soft limit... It'll lower throttle, reduce wastegate DC to stay in this range... This is where I suspect you are hitting your limit...

I mentioned Absolute MAP readings because all OEM pressure referenced values are based off Absolute MAP... If you log in absolute map, all you need to do is either log BARO, subtract that from your absolute map reading to get boost pressure... Or simply look up the baro conditions on a weather app for your location when you are logging and subtract your absolute map value by that to get your boost pressure... You should never waste a data pid logging "boost pressure" If you don't get to select looking at the tune in imperial or metric values.. Chances are the OEM tune is based in Metric values... which means it'll be in kpa, not psi like I've mentioned..

You asked about Open Loop functions... There's actually 3 states the ECU can run in... Closed Loop, Open Loop and something called Open Loop Drive.... Closed Loop and Open Loop Drive are the 2 most common states.. Open Loop is a transitional state, used during things like warm up enrichment, or going from decel fuel cut, back to closed or open loop drive... The ECU has 2 strategies for switching out of closed loop and into Open Loop Drive... Load based, and APP position based.... You've got RPM based Cloosed loop tables with load values in them... when the car exceeds those load values it engages the closed loop counter.. You need to stay above the load value long enough for the counter to count down before it'll switch into Open Loop Drive.. This counter isn't something you'll see in any scan data, it's not a traditional time value either... There's also RPM based APP threshold tables.. 5 of them... These define the APP position % to trigger WOT conditions... Stock tune has some of these tables with values above 100%... This means there are times when the stock tune will never trigger a WOT condition... If you set all of these tables about 100% you'll never trigger any of the WOT fuel tables, or other WOT related command tables... If you set this to lets say 5%... you'll be running on all your WOT tables above 5% APP...

COBB and Versatuner show 3 closed loop max tables... This is supposed to be for fuel trimming function during WOT conditions... I've read this is a Gen2 ecu function that COBB and Versatuner have implemented into Gen1 coding... It doesn't appear to work on my Speed6...