%Throttle = WOT = Close-Loop Mode ???

[cobalt]

On the NSX, what percentage throttle application forces the ECU into closed-loop mode (i.e. what does the ECU consider to be WOT?).

The reason I am asking, is that I dynoed last week at 245rwhp, then tuned my A'pex S-AFC to lean out the fuel map to yield 251rwhp. I have the "Hi-Throttle" point set at 85%, and have kept the Lo-Throttle map untouched from OEM (i.e. zero correction). Now, a week later - and about 500 miles later of street driving, I dynoed again with the settings I had before, and put down the 245rwhp, which is the same as my first baseline dyno.

I suspect that the OBD-II is compensating for my tuning changes of the fuel map.

Thus, if I know which % throttle application puts the ECU into closed-loop mode, I can adjust my Hi-Throttle point to that percentage, so that the ECU won't "learn" and compensate for my fuel map adjustment.

Thanks in advance,

Andie

 

[DocL]

All I can think is that there's too much engine management things to tinker with. Why not keep it simple like me and you'll constantly pull 251rwhp with minimal mods.

BTW, your car sounded incredible on the dyno!

 

[cobalt]

Hehe...I just want to get back to where I was at 251rwhp...

I just found it funny that after a week or so of street driving (500 miles or so), that I ended right back at 245rwhp. This leads me to believe that the ECU is learning to compensate, since the Hi-Throttle map and Lo-Throttle map were being interpolated.

With intake, headers, and exhaust, I should be putting down around 255-260rwhp, just like I did when I dyno-tuned it about a week ago...so something fishy is going on.

I plan to reset the ECU, turn the A'pex controller to zero-correction, and do 2 pulls to redline for the ECU to "learn", and then do a baseline dyno. From the baseline dyno, I will tune the A'pex for better A/F ratio, which should yield 5-7 addition rwhp as it did before. Then I will drive around all day...and redyno later in the evening, and see if the fuel map settings are "lost" (i.e. the ECU has compensated). The S2K guys have had problems with the ECU's compensating for A/F tuning done with the A'pex.

What I will do is determine what voltage/% throttle application is considered to be WOT by the ECU (i.e. closed-loop mode). For example, if it is 75%, then I will set the Lo-Throttle point to 75%, and then the Hi-Throttle point to 76%, and just tune the Hi-Throttle map. Thus, when the Hi-Throttle map comes into play, it will only be adjusting A/F deliver at WOT, which the ECU does not compensate for via O2 sensor signals.

From the 251rwhp (257rwhp in STD) I got last time with fuel map tuning, I think I should be able to fine tune it to around 265rwhp, at which point I'll be happy. I have put on the new A'pex Power Intake, which tested better in filtration and flow than the K&N cone filter, and have enclosed it inside the OEM air-box...so this should help incrementally...probably just 1rwhp, hehe.

I'm gunning for 265rwhp with just intake, headers, exhaust, and fuel tuning...and if I can keep it at that, I'll let it rest.

-Andie