Re: Lambda Testing by SM

[QSHIPQ@aol.com]

In a message dated 98-06-17 14:40:09 EDT, you write:

<< 
CO or Carbon Monoxide percentage goes up when you have rich mixtures,
i.e. lambda less than 1.0 and it gets very low when you have lean
mixtures, lambda greater than 1. Possibly you are confusing CO with CO2
(Carbon Dioxide) but this gas tends to be peak near the lambda value of
1.0 and it drops off if you go rich or lean. My years as a licensed
emissions repair technician in California certainly drilled in the
basics of exhaust emissions.
 I have two graphs showing these relationships of the exhaust gases and
 air/fuel ratios on my web site at
 
 http://www.teleport.com/~scottmo/ecu20v.html#o2
   >>
Scott, FYI, my copy of Probst book has fig 2-8 listed respectively top to
bottom, HC, NO and CO.  Bad on Probst, he has NO and CO reversed (and me for
not thinking).  Your copy of the book appears correct, mine isn't, but I do
have other reference material that corresponds with your second graph of CO,
CO2, HC and NOx.  Everything in print must be correct? (Probst advisory
alert!!!)

Given a high CO content, high HC and High CO2, I would still question where we
are getting combustion.  Long term HC content has bad effects, regardless of
FI or carbs.  Fuel is either burned or not burned, when it's not we have a
myriad of potential problems.  Hot turbochargers and exhaust manifolds might
be "correcting" that, but how?  By burning the unspent fuel?  Doesn't sound
like good long term news for the O2.  Or the longevity of the EM.

The fact that the tuners are using 11:1 fuel ratios is intriging to me, cuz
the ONLY thing we can surmise is reduced manifold temps.  Given that these
values you posted are based on the old 'fixed duty cycle'  technique of WOT
(and so really is the S4) I sure would sure want to make doubly positive I've
properly adjusted my WOT switch.  And in a early MC car, that's not even close
to WOT.  

Interesting to note too, Scott is that the Bosch manuals refer to the .85-.90
target for WOT operation for maximum power.  The interesting quote in the
manuals seems to be:  
"When the throttle valve opens suddenly, the air-fuel mixture responds by
leaning out briefly.  This is due to the fuels restricted vaporization
potential at higher manifold vacuum levels (increased tendency to form fuel
layers on intake tract walls)  To obtain good transition response, the mixture
must be enriched by an amount which varies according to engine temperature.
This enrichment privides good acceleration response."

Hmmm, if I insert an EGT temp sensor to do the "vary according to engine temp"
would I be accomplishing a better rich mixture and transition response?
Certainly better than how audi does it now?  Would a better O2 do the same
thing?  
  
Very interesting discussion you started Randall.  Hope this makes you feel
somewhat better about posting in the first place.  

HTH

Scott