Intake / Exhaust Cam Angle Map Questions

Sorry for this being two questions in one post but i have a few questions i cannot find clear answers for that go hand in hand.

I have a 2018 WRX STI with a new IAG 700+ full build, that i have tuned using opensource follwing the videos and love where it is today.

I have started to tune the Intake Cam Advance and have gotten it to where i like it but had a few questions.

#1 - Can someone explain the true diffrence between Cruise and Non-Cruise maps and when does the ECU Choose to be in each map ? Basically what drives the ECU to be in one or the other at any given time.

#2 - There are cruise and non-cruise maps for each Intake and Exhast Cam Advance Angle (AVCS). Can i just combine the Two intakes cruise and non-cruise using the same process as we did in the Base Timing class using a single map ? Is there really a need to have them diffrent ?

If so then i really do need to know the answer to #1 granted i still want to know no matter the answer to #2.

Thanks in advance.

Scott,

That ECU doesn't have cruise and non cruise maps, so that sounds like an open source quirk. There are AVCS target tables based on TGV position open or closed though, which is perhaps what you're seeing.

With TGV in place, they generally should be different, as airflow into the cylinder head is different.

You are not correct on that, "That ECU doesn't have cruise and non cruise maps,". Even in the class videos they show them on their ECU as well and tune them. If they mean something else then ok but they are there,

And also you said "With TGV in place, they generally should be different" Are you saying everything in the classes are taught wrong ? Becouse in all the videos they do combine them and they are not diffrent. Hp Academy is doing all this wrong .... Doubtful...

Scott,

Open source definitions are very often incorrect or not entirely accurate/representative, and based on what you've said, this sounds like one of those cases.

HPA referring to what they see in software does not make HPA wrong, nor does it make you wrong for repeating what HPA says or what you're seeing in software. I am not saying you're reading software wrong, or not seeing what you say you're seeing.

I'm just letting you know the table names in the software you're using do not reflect how the logic in an 18 STI ECU actually works, so tables may be labelled cruise and non cruise, but the 18 STI ECU logic for AVCS table switching is based on TGV position, including blending between tables based on a TGV open ratio monitor which operates during and can continue shifting after the physical flap motion completes. Open source may or may not give you access to that monitor, and I don't know if they have it properly defined, but if you can access that and it is correct, it will tell you the weight of the tables currently in use.

TGVs can be open or closed while cruising or not cruising based on various TGV thresholds related to RPM, airflow, coolant temperature, etc. so cruise and non cruise doesn't really indicate which table is active.

I hope that clears up any confusion.

Does the vehicle being tuned in the course have TGVs deleted?

That is a much better statement than saying it does not exist and that its a open source quirk.

Now for the part of them being diffrent clearly its not needed since in the lessons they do show combining them on the tune side both whats called the cruise and non-cruise for timing and other maps.

Both of the factory maps cruise and non-cruise Intake Cam Maps when side by side are the same minus about 8 cells which on cruise is 3 deg higher / diffrent from non-cruise. So clearly they can be the same especially when my map for cruise/noncruise in those cells are more conservitive in those cells when combined.

The real question am i really losing anything from combining them as well as are we leaving anything on the table combininng the other maps as shown in the Lessons ?

No TVG's are not deleted ... I am also in a state with emmissions so cannot without possibly effecting my emmisssions ...

Scott,

I'm sorry you took offense at my initial comment, but please understand this forum is not like many others, not like FB groups where people are bashing each other, and that's certainly not what I was doing. I just have to preface any comment about how things work on open source with some reference/warning because there are significant issues in many open source definitions I've seen, especially those from the last decade, so what you're looking at is often quirky, possibly misleading, may not behave as you'd expect based on what you see in front of you.

An optimal calibration would have different values in each table, as airflow into the cylinder head is different depending on whether the flaps are open or shut, but yes you could make the tables the same and the vehicle would certainly drive that way.

If the tables are made the same, the system would no longer account for conditions where you're at light load and TGV are open, or moderate load before TGV have opened, because there are delays in the TGV open/close logic so you cannot assume which condition TGV are in purely based on RPM/Calc load.

If the flaps are deleted in a non emissions controlled environment, then the airflow change is no longer present and I would expect values to either be made the same, or more typically you make the ECU operate at TGV open at all times since the TGV can't actually close if the flaps aren't there.

Since you mentioned you are in an area with emissions regulations, and I'm glad to hear you're looking to abide by them, I can tell you that from experience with that car in an emissions laboratory that retaining the stock values in light load areas of the AVCS target tables is your best bet.

You can make the car clean with the TGVs open in some more conditions than stock after careful tuning, but I still have the AVCS targets differing between open/closed states.

Well for full disclosure yes my mind since spending time in other forums did go to a defensive posture. Some if not many forums do get toxic.

There is nothing wrong with Open Source tuning at least with my 2018 WRX STI Everything has worked perfectly and i was expecting issues but have had none. And the default Basis from tuners against open source is getting a bit old. I do have a bias against COBB and it was the driving force to find another solution, and keeping with emissions going after market was not an option. That is why i chose Open Source And i have had nothing but great outcomes with open source so far. Now knowing that the titles of the maps might be a bit off based on what it really might be makes more sense.

Hope you did not take offense ... none was meant to be given just a hard push based on past forums

Scott,

Helping you and other users here is literally one of my jobs, so that's what I'm hoping to do. :)

I'll just suggest continuing to use caution which you're likely doing anyway as you learn more about the tuning process. Table names aren't the only difference with open source, so save every revision along the way, if you see something happen in a log that you're not expecting, carefully investigate, potentially go back to the prior file.

Back to your original question...when you're using software that doesn't make it clear when one of two tables would be active, one way to know the outcome of your changes is to make the tables have the same data, rather than leaving the tables with differing data without knowing all the logic controlling the switching, perhaps without the monitors needed to see the switching occurring in logs. It's as safer strategy to teach a novice. Your question was very specific so I gave you my thoughts, but honestly I hadn't watched that course so I didn't know I was suggesting something different from what was shown.

As a heads up, you mentioned there's only about 8 cells with data differing up to 3 degrees between the cruise and non cruise AVCS target tables. On USDM 2018 STI I took a look for you in what I consider a known good ROM, and I'm seeing more cells with differing data, and more of a difference between them. What you are seeing could be related to the definition info, scaling, or perhaps the file you started with that you thought was stock maybe wasn't actually stock? Getting known good stock files is actually one of the tricky parts of using open source. I don't have a way to provide this stock ROM in open source software format, but in case it helps, you should be seeing a variance of up to 23 degrees in one direction and up to 13 in the other direction between exhaust AVCS target tables (dozens of different cells), and up to 5 deg in the intake tables (23 different cells).

So with that i went to a friends known stock 2018 WRX STI and pulled his rom ... amost exact there were some less cells in mine that diffrered but who knows it might have been tweaked from the last owner or a newer or older revision rom from factory who knows. Attached a screen shot.

And yes i keep every version of each tweak if i have to revert for any reason or see anything that does not align to what i belive should happen and i start again.

I'm checking in to see how it's going. Hopefully well?

Extremely well yes i did merge the two maps. and got the tune to where like it ... Thank you for your help and info

Awesome, glad to hear it.