EFI tuning- Target AFR?

[auditude at neta.com]

Yeah, you would need a wideband O2 sensor, which requires a
controller to interpret the output.  They are expensive.  You can
save some money by constructing your own, but it still isn't cheap.
 There is an effort to do this going on at diy-efi.org

Ken

Brian Devlin bdevlin at stanford.edu wrote:
>
> Most O2 sensor don't distinguish between rich and really rich, it's
> pretty much an on-off situation (I think there are some $pecial ones
> on some Japanese cars that use an amplifier to get a more linear
> signal, but I'm not too sure). Without cycling between rich and lean
> you really aren't going to get info from the sensor and the computer
> will have to guess. That might be fine for power, but unless you're
> adding a smog pump it'll be hard on the cat if it's rich all the time
> (if you have one, of course). -Brian -86 5ktq
>
> >Hey guys,
> >Just wondering what the best AFR for the Audi 10v turbo motors is.
> >I'm about ready to install the EFI system, and I need a bit of advice
> >on what air-fuel ratio I should aim for in high boost. I know that
> >the turbo Dodge motors do best with a really rich mixture (.9v or
> >more from the O2) but I haven't really seen this discussed regarding
> >the Audi motors. I just don't want to melt a piston :) Any help is
> >appriciated. Thanks Mike