[T3] Lean Cruise

[Max Welton]

--- On Fri, 3/8/13, Jim Adney <jadney at vwtype3.org> wrote:
> > The amount of ignition advance appears to have an
> effect on measured
> > AFR independent of the amount of fuel being supplied. 
> 
> So you're not getting an accurate measure of A/F? I wonder
> if this is 
> affected by NOX content. That might change with advance, or
> certainly 
> by lean burn.

In practical terms, I've observed that the AFR reading seemed to move in the lean direction when timing is advanced, holding the injector pulse-width, MAP and rpm constant. But I could easily be wrong on this point. It was a tough test to do without a dyno or the ability to change timing on the fly. I had to do it in two separate trials on the same stretch of road.


One of the things I have to take on faith at this point is the accuracy of my AFR measurements. I previously used the WB system from Innovate, but last year switched to the one from AEM. The readings between the two devices seemed consistent at least.

http://www.innovatemotorsports.com/products/lc1.php

http://www.aemelectronics.com/inline-wideband-uego-controller-1159

And here's a crappy picture showing the sensor location. I have a much better one, but I can't find it right now.
http://images.thesamba.com/vw/gallery/pix/671713.jpg

Max Welton
http://www.maxwelton2k.net/