Custom ported and CNC throttle bodies, upper and lower manifolds by Synergy Composite

wstar · 07-01-2014, 07:18 AM

Yeah, I don't believe we get the target AFR behavior in open loop mode. Open loop is still really open loop. That said, surely it's at least somewhat influenced by the ECU's learned trims from closed loop when it goes into open? I have no idea, just speculating.

synolimit · 07-01-2014, 07:39 AM

Quote:

Originally Posted by wstar

Yeah, I don't believe we get the target AFR behavior in open loop mode. Open loop is still really open loop. That said, surely it's at least somewhat influenced by the ECU's learned trims from closed loop when it goes into open? I have no idea, just speculating.

To me closed loop targets 14.5 at xx timing, pretty basic. Open is by itself targeting whatever AFR and timing you're running based off of load and rpm.

wstar · 07-01-2014, 08:03 AM

Quote:

Originally Posted by synolimit

To me closed loop targets 14.5 at xx timing, pretty basic. Open is by itself targeting whatever AFR and timing you're running based off of load and rpm.

?? Maybe I'm misunderstanding you, or I don't understand this **** as well as I thought I did. I thought our AFR target maps (the ones you can modify based on rpm/load/whatever) were what it used in closed-loop mode to realtime-tune the fuel trims based on feedback from the upper O2's to reach the desired target AFRs.

I also thought, by definition, "open loop" meant you're running on a fixed set of fuel tables (perhaps including recently-learned trims from closed-loop mode) but *not* using AFR from the upper O2's to modify the fueling in realtime to try to reach a specific target anymore. In other words, closed loop is based on realtime feedback, and open loop isn't.

synolimit · 07-01-2014, 08:11 AM

Quote:

Originally Posted by wstar

?? Maybe I'm misunderstanding you, or I don't understand this **** as well as I thought I did. I thought our AFR target maps (the ones you can modify based on rpm/load/whatever) were what it used in closed-loop mode to realtime-tune the fuel trims based on feedback from the upper O2's to reach the desired target AFRs.

I also thought, by definition, "open loop" meant you're running on a fixed set of fuel tables (perhaps including recently-learned trims from closed-loop mode) but *not* using AFR from the upper O2's to modify the fueling in realtime to try to reach a specific target anymore. In other words, closed loop is based on realtime feedback, and open loop isn't.

Subi is switched. Real time is open loop but with a non wide band O2 it can only read and adjust down to like 11.2afr which is bad when you need to run richer. Maybe nissan is different being NA. Megan should know.

07-01-2014, 07:18 AM	#1 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3595	Yeah, I don't believe we get the target AFR behavior in open loop mode. Open loop is still really open loop. That said, surely it's at least somewhat influenced by the ECU's learned trims from closed loop when it goes into open? I have no idea, just speculating. __________________ 7AT Track Car! Journal thread / Car setup details

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