SD tune, Targeting AF?

[freshda9]

This is maybe a very noob question in the GM world of tuning. I havent done much SD GM stuff but switched my truck to a COS SD 1bar tune. Typically if tuning other platforms or standalones in SD their are target AFR's for each cell as you go up in rpm and kpa. Typically over 50kpa i start enriching my targets. 0-50kpa 14.6, 60-75 13.8, 75-100 13/12.8 ranges.

Problem is i have been using closed loop trims and looking at multipliers etc but nothing i see changes from 1.00....
Should i make changes to Open loop EQ ratio (this is the only table that looks like a target table). But its open loop and when i go in clossed loop will it be ignored?

hp tuners 0001.jpg

I have purchased and read a few tuning documents but nothing i have read has been very clear on targets. I assume if i did a 2bar 3 bar SD tune you would want to dial the cells in also. Then work PE into the mix... Sorry guys just confused at the moment, probably over thinking something simplistic.

[mecanicman]

The ve table represents airflow. You don't use it to set afr per say, it tells the pcm how much air flow is into engine for that rpm/map value. Target afr is 14.7 or what ever you choose your stoich to be set at. Your PE(power enrichment) is where you dial in your desired enrichment afr. Can be restricted by rpm/map/torque/tps vs rpm. Multiplyer is calculated by taking stoich and dividing by what your desired afr will be. 14.7/12.5=1.176.

[freshda9]

Mecanicman: thank you for your reply. I understand VE is air modeling. I guess if going up a hill and not in PE i would imagine around 70kpa i would want more then stoich to cool and fight detonation. I guess i need some visual representations to understand clearly. I do understand HP's multiplier equation and have used it.

[mecanicman]

If you feel you need more enrichment at 70 kpa, then you set your restrictor to 70 kpa and make your tps low enough that pe enables.

[MikeOD]

If you're staying in closed loop, you're going to be at lambda 1 (14.7) whenever you're not in power enrichment...and then you just have a single row AFR vs RPM that you can command.

If you want to command any AFR at any time, you need to completely disable closed loop.

For 99% of the engine setups on the road, you can use closed loop and stoich and then setup your enable criteria for closed loop to enrich when it's needed and not when it's too late, and everything will drive fine.

[Maxspeed96ct]

The car uses feedback from the primary (front 02 sensors ) when in closed loop . But you still need your VE pretty close .


In Open loop on a SD tune it fuels strictly based off your VE .