LS1 Boost Custom OS

For discussion and distribution of custom code and hacks
Posts: 106
Joined: Wed Apr 11, 2018 8:50 am

Re: LS1 Boost Custom OS

Postby bubba2533 » Fri Apr 30, 2021 3:06 pm

Well, I'm probably spending way too much time on this as I have no idea if anyone else is even going to use this when I'm done....but I am making good progress.

From my original post here is an update on each of the features.

[Done] -Update MAP Variable Limit for 3/4 Bar Map Sensor
[Done] -Increase Size of VE Table and Increase Range for 3/4 Bar MAP
[Done] -Disable Part Throttle Baro Update (Already figured this out)
[Done] -Spark cut launch control
[In Progress] -Add New Table Timing adder vs. 3/4 Bar MAP
[In Progress] -Modify MAP range of EQ Ratio vs. MAP vs. Coolant Table (Gas & Alcohol) No need to increase table size IMO.
[N/A] -Disable PE (Not disabled, but no need to tune it with the above Boost EQ Tables)
[Not Started] -Open Loop Boost Control (lots of different ways this could be implemented)
[Not Started] -Overboost feature (Spark cut?/boost cut?)

I also have a couple other timing related features that were a part of my original launch control I'm going to include.
[Done] -1D Timing Adder Table vs. MAP when LC is active (Helpful to build boost)
[Done] -1D Timing Adder Table vs. Seconds since launch (brake/clutch must deactivate LC)

Posts: 19
Joined: Thu Jan 19, 2017 11:09 pm

Re: LS1 Boost Custom OS

Postby Stokes1114 » Sun May 02, 2021 8:16 am

I know I'm watching with interest as are others. I'll give it a shot once I have everything sorted on my build. Wonder if it would be possible to port it to 6125 OS. If not, I have no problem slapping a P59 in there.

Posts: 106
Joined: Wed Apr 11, 2018 8:50 am

Re: LS1 Boost Custom OS

Postby bubba2533 » Wed May 05, 2021 3:30 am

I haven't looked at any P01 OS, but I'm sure it's possible. Just not sure if it's worth the time.

I think I've gotten it to the point where I think it's worth releasing, but I will probably give it another once over after I take a break to make sure I didn't miss anything. Also probably do some bench testing, which would be a good idea since so many things have changed.

I'm going to hold off on adding boost control as I haven't decided how complicated I want to get. This new code has taken up quite a bit of the available CAL space that I created in the EGR area. So if I want to get fancy with the boost control then I might have to find more space. If anyone has recommendations on how they thing boost control should work let me know.

Here is the current feature list:

-Increase MAP Variable Limit (375 kpa Max)
-Increase Size of VE Table (15-375 kpa, 10 kpa increments)
-Disable Part Throttle Baro Update
-Spark Cut Engine Speed Limit
-Spark Cut Launch Control
-Spark Cut Flat Foot Shift
-Boost Spark Adder vs. MAP (105-375 kpa, 10 kpa increments)
-LC Spark Adder Table vs. MAP (15-285 kpa, 10 kpa increments)
-Launch Spark Adder Table vs. Time Since Launch (0.0-4.0 sec)
-EQ Ratio vs. MAP (20-340 kpa, 20 kpa increments) vs. Coolant Table (E0 & E80)
-Disable PE (Set EQ Ratio to 1.0 since no longer needed) I could Disable this, just not sure if it matters.

If anyone has any questions about a feature let me know so I can clarify.

Another thought that I've had is to disable knock retard when LC is active. The spark cut has caused me to see false knock during LC which isn't really desired.

Posts: 350
Joined: Sun Apr 10, 2016 9:20 pm

Re: LS1 Boost Custom OS

Postby kur4o » Wed May 05, 2021 4:29 am

I am not sure if it is off topc but did you find the max tables` size to use with this pcm code.

The biggest I see in cal is 37x29.

Posts: 106
Joined: Wed Apr 11, 2018 8:50 am

Re: LS1 Boost Custom OS

Postby bubba2533 » Wed May 05, 2021 5:37 am

The tables are no bigger than the stock OS because the VE table 15-375 kpa is made up of 2 tables. I rescaled the MAP variable therefore increased the range of the stock VE table to 15-195 kpa and created a second VE table for 195-375 kpa. This way I saved some CAL space.

The limit would be based on the tbl_ instructions which I had no reason to do. And then you could always segment the tables up like I did. No idea why you would ever want a table that big because it would be very difficult to tune.

Posts: 350
Joined: Sun Apr 10, 2016 9:20 pm

Re: LS1 Boost Custom OS

Postby kur4o » Thu May 06, 2021 5:20 am

2 tables will keep it nice and tidy.

I was curious what is the theoretical limit of table size. I know older 8bit pcms have some limit for it.

Once I looked how commercial custom OS work, and they ditch some of the Piston protection code and replaced the afr target there.

If maf is not used, some patch to proper disabling it might worth looking at.

Some table that might be beneficial is spark retard vs map[boost] vs intake temp.

On a side note isn`t a vacuum scalar better to use than a simple map read out.

Posts: 106
Joined: Wed Apr 11, 2018 8:50 am

Re: LS1 Boost Custom OS

Postby bubba2533 » Thu May 06, 2021 2:23 pm

kur4o wrote:If maf is not used, some patch to proper disabling it might worth looking at.

I did actually think about that. I know the way I did it was failing the MAF with P0103, which I believe disables one of the base spark tables. But I don't really think anyone needs both. If anything I want to try and simplify the function so that it's predictable and easier for people to tune. There may be other things that it also impacts.
kur4o wrote:Some table that might be beneficial is spark retard vs map[boost] vs intake temp.

There is already a g/cyl vs. IAT spark adder table.

kur4o wrote:On a side note isn`t a vacuum scalar better to use than a simple map read out.

Not sure what you mean.

I really just wanted to try and give people another option for tuning a boosted setup on the stock PCM because I've used both HP Tuners and EFI Live and wanted to try and make something that was better IMO. I also didn't want to spend years developing it so there are drawbacks to the way I'm doing it.

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