Car: 04 STI

Would it be possible to put my techedge wideband in instead of the narrowband sensor on the exhaust (near the midpipe) and then wire the 0-5v signal from the techedge controlbox to the wires on the oe sensor? so I do not have to have 2 sensors, and then have the signal react faster? Or would the ecu not be able to handle it?

/Jesper

 

I am considering same setup on a MY99 GT. From what I have found Techedge sets the folowing guidelines:

• The sensor should always be placed on the engine side of a catalytic converter, unless you are testing the effectiveness of the convertor itself.
• The gas temperature to the sensor should never exceed 850 degrees C (about 1560 degrees Fahrenheit).
• The sensor should never be run without power to the WB unit (a hot sensor burns off carbon residues)
• Always have the long axis of the sensor perpendicular to the gas flow (stops sensor clogging)
• Position the sensor vertically or at most between 10 o'clock to the 2 o'clock position (this avoids cracking the internal ceramic structure should moisture condense internally)
• We don't recommend using a short sections of exhaust pipe shoved up your tailpipe. A specially welded additional bung is the best mounting strategy.

Since the simulated narrowband is designed to match a Bosch LSM-11 I cannot se any downsides with this setup besides the simulated narrowband can be too quick for the ECU. I do not know if it is a problem that the sensor reads the partial pressure of gases in the exhaust and infers the AFR, rather than measuring some magical AFR directly.

http://bbs.22b.com/cgi-bin/ultimatebb.cgi?ubb=print_topic;f=7;t=000469

 

anyone with input to this setup?

 

It's very simple.

Wire the NBsim (pin 3) output into your O2 sensor signal wire on the ecu loom (blue connector pin 21).

This will make your car run with the wideband installed in the down-pipe rather than the oem narrowband.

But, as mentioned above the output is similar to the LSM-11 sensor which is different to the oem sensor. This will make you run rich at cruise and idle. The best thing to do is use the config utility ( http://wbo2.com/sw/conf-afr.htm ) to set the NBsim output to target whatever AFR you want at cruise.

I target 15.1:1 cycling between 14.9-15.3. This gives good economy whilst maintaining a smooth idle and cruise.

Simon

 

thanks - I was starting to wonder if nobody actually uses this setup

What about the two problems discussed on the 22b board - does not look like they ever came to a conclution

- the simulated narrowband can be too quick for the ECU
- the partial pressure of gases in the exhaust and infers the AFR vs. measuring some magical AFR directly?

 

There's always going to be lag between what the sensor reads and what is going on in the combustion chamber due to when the ecu is altering fuelling, the sensor isn't going to see the exhaust gases for a finite time as it travels through the head, down the headers, up-pipe, through the turbo until it eventually hits the sensor in the downpipe. I have been able to get very accurate control cruise and idle AFRs without difficulty.

Your second question I presume relates to different oxygen content fuels? The oxygen sensor measures lambda. It then applies what you tell it about the fuel you are using to give an AFR ie for normal petrol stoich (lambda=1) is 14.7:1. If you were using 100% methanol stoich would be around 9:1. So if you add methanol to your petrol for example, you will shift stoich towards 9:1.

The ECU closed loop fuelling targets 0.6-0.7V as lambda = 1 for whatever fuel you put in, at least on the oem preMY01 narrowband. As such if you re-configure the NBsim so that an AFR of 15:1 lies at around 0.6V the ecu will target that in closed loop.

It'll take a few flashes to get your targeted afr and swing right.

Good Luck

Simon

 

If you have an ecutek remap on a newage STI, you can change the closed loop cruise afr. The 04 STI comes with a much more accurate sensor than the pre01 cars.

Do you want to use it for tuning?

Paul

 

Here's a more detailed description on how to re-configure the NBsim output.
http://bbs.scoobynet.co.uk/showthrea...light=techedge

The 22B link from above is outdated, as it is from before the config utility supported changes to the lookup tables.

Paul, so does that mean you can tell it to target 15:1 closed loop using the oem sensor?

Simon