% Coolant Contribution Table Smoothing

[K1ng0011]

This is regards to the "% Coolant contribution for calculating charge temp vs RPM & MAP" table within OSE12P. I know that smoothing the spark table is something you want to do. That way there are no large jumps in between the spark table cells. Looking at the stock OSE12P % Coolant Contribution Table has not been smoothed out. Is there any reason to smooth or not smooth out this table. I have posted screenshots below.

Original OSE12P Table.PNG (62.27 KiB) Viewed 3413 times

Smoothed Table.PNG (58.43 KiB) Viewed 3413 times

[antus]

Which bin is that in? The table itself tells the pcm how much to weight the temperature of the air and how much of the coolant when calculating the charge temperature in the cylinder. As its going to be used as a % reference to two other values, I dont think it is going to make a huge difference, but I cant see any reason not to smooth it, either. Essentially what its mapping is how the coolant has less effect on the temperature of the air when its moving in to the cylinder quicker (less time for the air to absorb heat up from the head and block before it is ignited).

[K1ng0011]

This is from the OSE12P .bin (OSE $12P V112 BLCF V8.bin). So based on your description of what this table does I wonder if the table should have the general shape like the one I have below. The quicker the air is moving through the intake the less time the air has to absorb the heat from the intake, heads, etc. So the higher the KPA the closer to wide open throttle you are and the more you want to rely on the the air temp sensor. The original table has a dip near 2800RPM near 100KPA. Then as the RPM increases toward 6000RPM the table goes back to relying more on the coolant temp sensor again. Based on your explanation on how the table works this does not seem right to me. Unless there is something I am missing here of course.

New Table.PNG (44.57 KiB) Viewed 3397 times

[Dylan]

Leave it stock mate unless you change the intake

[pman92]

There's all sorts of thing's at play. The speed of the air (RPM) as well as how dense it is (Kpa) will both contribute to how much heat it gets off the port walls.

Unless you have some reason to change it leave it standard. Especially if using a standard intake, GM engineees would of spent alot of time getting it right.

If you find your fueling changes slightly at the same RPM/Kpa but different COOLANT TEMP, use this table to correct it.

If you find it's changing across the board (all different RPM and Kpas) as the AIR TEMP changes, change the inverse charge temp table.

If you find it changing in 1 spot as the AIR TEMP changes, you will have to change this table to use more coolant temp though.

Both tables (coolant contribution and inverse charge temp) work together. They would be very difficult to calibrate perfectly, if that's even possible.

Small changes and making sure everything else is right first (VE etc) would be important

[pman92]

Another thing at play along with air speed and pressure would be the resonance of the intake.

The dip at 2800rpm on the factory table 100kpa probably corresponds to where the resonance of the air pulses in the banana intake is getting the air in faster as the valve opens

[vlad01]

I found the most relevant is the inverse temp table. I havn't needed to touch the contribution table but have worked the inverse temp one before to get the warm up to correctly follow the AFR once the VE was perfect at operating temps.

I know the contribution table can be useful to tune for cams that have a lot of reversion and thus heat the MAT sensor but even then I have had luck where it was good as default anyway.

[K1ng0011]

Thank you everyone for replying and giving more information on what this table is doing. I might smooth the table just to test it but other than that I dont plan to make any further changes at this point since I have a better understanding of what the table is for.

[delcowizzid]

It's pretty much calibrating the air temp sensor and how it heats up in the runner at idle leave it stock of the inlet air temp is still in the runner