AutoVE with nb02

[Biggsy]

First of all I would like to say hello to everyone in this forum! I have found a wealth of information here which has helped me MANY times over.

The question I have : Is it possible to AutoVE tune using the car's 02 sensors?

I was thinking along the lines of setting the A/F to stoich throughout the tables. Setting timing low around WOT (try to avoid detonation) , and logging percentage between commanded and actual

Has this been discussed before?

Cheers
Dave

[Tordne]

The answer is yes you can, but no you shouldn't.

The NBO2 sensors are not at all accurate above or below stoich. The NBO2's work on millivolt switch points which may or may not be exactly on the expected 14.63:1 AFR as well.

Definitely recommend a WBO2 controller, in fact I'd go so far as to say it is mandatory :)

[Biggsy]

Thanx Andrew,
I do have a WB02 perminantly installed in my car and that is what I use.

It was just a thought I have had for a while that I just wanted to throw out there for discussion:)

Dave.

[joecar]

WOT requires running richer than stoich, but the NBO2's only indicate stoich accurately.

[Doc]

Kinda sounds like cutting a fart but not smelling it.;)

[SSpdDmon]

Well, the flip side is you can tune a part of the VE by using the NBO2's. As long as the car stays in closed-loop operation, you can log the STFT and LTFT average %'s against a VE map or MAF map (one the VE is close). I posted a spreadsheet a while back that allowed you do this, which can be found here: http://forum.efilive.com/showthread.php?t=4092&highlight=spreadsheet

If the link gives you trouble, pm me your email addy and I'll send it to you.

[joecar]

Jeff, thanks for the link. :cheers:

[SSpdDmon]

n/p

[Biggsy]

Well, the flip side is you can tune a part of the VE by using the NBO2's. As long as the car stays in closed-loop operation, you can log the STFT and LTFT average %'s against a VE map or MAF map (one the VE is close). I posted a spreadsheet a while back that allowed you do this, which can be found here: http://forum.efilive.com/showthread.php?t=4092&highlight=spreadsheet

If the link gives you trouble, pm me your email addy and I'll send it to you.

Link works well :thankyou2:

Dave.

[SSpdDmon]

Just an FYI...

If you plan on using the NBO2's, you want to set your filters up as follows:

Exclude data where TP% is changing more than 2% every 500ms OR
Exclude data where Fuel Trim Cell is greater than 19 OR
Exclude data where STFT's are less than 0.01 AND
Exclude data where STFT's are greater than -0.01

The first setting is personal preference. I like mine rather aggressive to eliminate the transient fueling. The second eliminates the WOT, cold start and open-loop decel parts of the log. Finally, the last two eliminate any laziness in the NBO2's. You could include one filter based on coolant temp....but, I wouldn't recommend starting your log until the car has been running for at least 20 minutes. This is because coolant temp gets to normal levels almost 2x as fast as oil temps. Vette guys know this as they can see their oil temps. Unfortunately, the f-body guys (like myself) aren't privelaged to this info. ;)

[Alvin]

I wouldn't be afraid to use NB's to do part throttle. Thats the operating range they where designed for.

Try using LT % vs VE then after thats done use it to clean up the MAF table. I think the results will surprise you.