AlexEvo6

iTrader: (1)

Well, this is an open question. My aim is to change the target AFR for closed loop. Let's say for example I want 15.5 AFR rather than 14.7

The purpose is just to have maps for daily driving (fuel economy) and alt maps for track use.

For info, it's a VI RS2, running a VIII ecu with 96530006 Tephra 5.10 rom

I know I can use the simulated narrowband output from my zeitronix and change the threshold. There is also a thread which provide some info about using the linear WB output.

BUT I wonder if it's possible to achieve this using the OEM narrow band ?

logic

iTrader: (2)

The OEM narrow-band O2 sensor is considered "narrow" for a reason; it's only accurate at or around 14.7:1. From this article:



I wouldn't trust any reading outside the range around 14.7:1. You really do need a wideband sensor with predictable output to trust any non-stoich value.

Once you have a wideband available to you, then mrfred comes to the rescue, with ECU-driven table-based AFR control.

AlexEvo6

iTrader: (1)

Thanks, my concern was about WB accuracy at low RPM and "heating time"...
Will use WB output data

fostytou

iTrader: (15)

For the most part *not really*. The problem is not in the definition, but in the sensor itself. Narrowband sensors are only accurate at 14.7 AFR. their inaccuracy is orders of magnitude larger every little bit away from stoich. Even if you could tell the ECU to look for 15.5AFR it would be very difficult for it to try to maintain that with any degree of accuracy.

mplspilot

iTrader: (7)

Look on ebay, there has to be those "fuel saver" things that alter your stock O2 NB signal. All you need is something that would add ~0.100 volt to the stock O2 sensor signal. Has to be easy enough.

Jack_of_Trades

iTrader: (17)

Google "transistor amplifier". IF you put in the effort, you can design a simple voltage adder yourself for only a few bucks.


Here is a start:

http://www.allaboutcircuits.com/vol_3/chpt_4/7.html