Changing 2004 GTO to 2 bar MAP OS

[llafro]

Working with a 2004 GTO. LS1 with a MP112 Magnacharger kit.

I am trying to change my tune file to use a 2-bar MAP sensor. I followed the directions to apply the different OS. It did change the MAP Sensor Linear parameter from 94.43 kPa to 200 kPa. However, the VE table has not been changed as it describes in the instructions. It only reads to 105 kPa.

I tried the same change on a 2000 Camaro stock tune, and the different OS is ported over. Both the MAP sensor limits and the VE table changed as they are supposed to. The data in the VE table shows all "5.19" as expected.

Why won't the 2004 GTO file change the OS?

[5FDP]

Post the tune.

[llafro]

Here are the two tunes.

2004 Pontiac GTO 57 Manual Trans Magnacharger Base Tune 2 bar OS.hpt

2004 Pontiac GTO 57 Manual Trans Magnacharger Base Tune.hpt

This is the change log:



Looking at it again, it does seem that the MAP range changed, but it seems to have kept the 1 bar data and spread it out over the 2 bar range:

Revised table (has 30-210 kPa readings by 10 kPa increments)


Original table (has 15-110 kPa range by 5 kPa increments)


This is what the VE table looks like when I did the same OS change to a 2000 Camaro tune (the MAP range is 15 to 210 kPa by 5 kPa increments):


Is there a difference in the PCMs and how they handle the different OS?

[5FDP]

Yeah it looks like that OS upgrades gives you the 210kpa VE but still only gives you the same amount of total lines because the resolution is cut in half now. Pretty common on the later OS's from what I always see.

You can just build your VE how you need too, pretty simple stuff.

[llafro]

You can just build your VE how you need too, pretty simple stuff.

Can I make use the table from the Camaro that I posted in place of the GTO one? How do I set up my own table with twice as many rows in the software? I don't see any way to manually go in and change the table setup.

Or are you saying to just enter the correct values into the table that's there? What about the lowest value being 30 kPa vs. 15 on the 1 bar table?

[5FDP]

Simple answer is that you can't do anything about what you are given.

The table resolution is set in stone, you can't change anything about that. The later P59's do not have enough room in the programming to support more resolution.

If you have a table that you have already made in another file as a starting point you have to get creative with how you put it into a calibration with less resolution.

Copy over each row that matches the other table. So in this case it's 30,40,50 etc etc and do that all the way to 210. Then highlight the whole table and you can interpolate and smooth the table with the smooth function.


The screen shot of the camaro file is of no use because it's just one solid number, that's just an auto fill type thing that still requires real number to be put into place. It also looks like you need to switch back to percent in the table. Right click > units > percent to bring it back to stuff you'll understand.

It's hard to say exactly how to setup your new 2 bar VE but a safe bet if you don't have a previous file is to use the stock data rows for 30-100kpa to fill that in. Then click 210 and plug in a number like 130, then highlight from 100-210kpa and interpolate to build a VE for boost. Of course lots of tuning with a wideband is required here to fix the fueling as this is just a starting point. Setting up your boost eq ratio, pe ratio correctly and using a wideband error is needed.

[llafro]

Simple answer is that you can't do anything about what you are given.

The table resolution is set in stone, you can't change anything about that. The later P59's do not have enough room in the programming to support more resolution.

If you have a table that you have already made in another file as a starting point you have to get creative with how you put it into a calibration with less resolution.

Copy over each row that matches the other table. So in this case it's 30,40,50 etc etc and do that all the way to 210. Then highlight the whole table and you can interpolate and smooth the table with the smooth function.


The screen shot of the camaro file is of no use because it's just one solid number, that's just an auto fill type thing that still requires real number to be put into place. It also looks like you need to switch back to percent in the table. Right click > units > percent to bring it back to stuff you'll understand.

It's hard to say exactly how to setup your new 2 bar VE but a safe bet if you don't have a previous file is to use the stock data rows for 30-100kpa to fill that in. Then click 210 and plug in a number like 130, then highlight from 100-210kpa and interpolate to build a VE for boost. Of course lots of tuning with a wideband is required here to fix the fueling as this is just a starting point. Setting up your boost eq ratio, pe ratio correctly and using a wideband error is needed.

So the VE table would look something like this to begin:



I pasted in the data from the existing tune file I have for the rows that line up from 30-100. From there, it's a case of putting in data that sort of lines up with the trend from 100 to 200 kPa. The boost eq ratio will be 1.35 to start all the way, while the PE ratio steps from 1.15 to 1.35 as RPM climbs.

I need to get the wideband set up so I can see what all is going on first. Without that, it's like walking in a forest at night.

[5FDP]

Yes, that table looks just fine to start with.

Often times depending on what else is done to the engine or fuel system the airflow model ends up needing to be scaled back because it's overly rich. It's better to be rich than lean in boost to start off with. Makes it's easy if say you were 10-15% rich and you can just go straight into the VE and subtract 10% worth of fuel, smooth it out and try again before really getting it dialed in.

[llafro]

Yes, that table looks just fine to start with.

Often times depending on what else is done to the engine or fuel system the airflow model ends up needing to be scaled back because it's overly rich. It's better to be rich than lean in boost to start off with. Makes it's easy if say you were 10-15% rich and you can just go straight into the VE and subtract 10% worth of fuel, smooth it out and try again before really getting it dialed in.

Thanks! I know the goal is always to start rich and work to lean it out as needed. It's much better than starting lean and breaking things. I guess it's just a quirk of the PCM that the table doesn't have the resolution of a 2-bar table, even if it does have the correct range. I guess a 3-bar OS would be the same? Not that I plan on doing that.

[5FDP]

Correct, a 3 bar OS would have less resolution as well. Those go up by 20kpa instead of 10kpa in the 2 bar.