re. EFI tuning- Target AFR?

[Ben Swann]

[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]

As per Probst - Bosch Fuel Injection & Engine Management, in the Tuning for
Performance and Economy chapter - "Peak performance is achieved with a
slightly richer air-fuel mixture (when lambda is approximately 0.9)"
however, the reading also indicates, close to peak power can be obtained
 by staying close to stoichiometric (14.7:1).  The graph shows this well,
 in that you are better erring toward stoichiometric than going too rich.
 Furthermore, the tailpipe emissions are best at stoich. and grow
exponentially as the mixture deviates - more CO and HC on the rich side (
cat poison and High pollution) or NOx peaking on the lean side, not to
mention melted valves and pistons.

Ben