Re: S4 Summa cum Lambda

["Randall C. Markarian" <asenna@accessus.net>]

Scott,

Just read the article.  It is interesting that not only did Audi find it
worthwhile to put said device on the S4, but also to promote the benefits of
the
device in an article.  One would think that Audi finds it pretty darn
important
to mention such minutia.  Could it be Audi knows something we don't know? 
Also
the article mentions that the S4's can run at full load much longer than
cars
without EGT sensor at a much cooler temps.  Cooler temps means more power
right.
Don't bother responding with 23k of info on why Audi is wrong, I just
thought it
was interesting.

Why do I bother sharing info?

Randall

----------
>From: QSHIPQ@aol.com
>To: quattro@coimbra.ans.net
>Subject: Re:  S4 Summa cum Lambda
>Date: Tue, Jun 16, 1998, 1:40 AM
>
>Er, ah, not sure this changes things much.  We are talking of WOT-free (maybe
>not soon) in terms of potential EPA regulations here.  Right now, on WOT,
>emissions are free, that is to say, most lambda circuits are bypassed in
>favour of a fixed lambda value or duty cycle.  A couple of reasons for that.
>First is that O2 sensors aren't the fastest animals in the world, and that
>gets worse as they age (in fact, many Ford 5.0 mustangs with freeflow exhausts
>actually run in limp mode cuz the O2 can't react to the flow).  So another
>measure could be used.  EGT.  For the moment, maybe a necessity, or a temp
>solution.  However, given the reaction of EGT vs time vs O2, I'm not sure that
>the EGT is the long term solution.  But for now, might get us closer to what
>the boys across the pond enjoy for HP.
>
>Too much fuel (HC) in the exhaust creates more than emission problems.
>Burning O2 sensors (especially with turbo cars) and melting cats are
>byproducts of too much fuel.  A major concern for the 100k emissions
>warrantees.  EGT measures may be the temp fix between fixed lambda WOT and a
>better O2 sensor.  What we really need is a better O2 sensor.  EGT is not
>really relevent to lambda, it is relevent only to WOT bypassed/fixed lambda
>values.  Stoichmetric is still a lambda equation, .86 lambda gives maximum
>power, 1.05 lambda maximum economy.  1.00 still is the best compromise of
>exhaust byproducts, the key is to address WOT and lambda.  EGT can do this.
>So could a better mousetrap (02 sensor).  
>
>Regardless, nice to see some 'cool' toys on the S4.  However, given the delays
>in the launch of said EGT equipped missile, I would venture that EGT is hardly
>a bragging right for the boys at Ingolstat right now.  Get the friggin bugs
>out of it, and get it over here....  Randall's ready!!!
>
>I'd advise you to just get a bug, but maybe better to just wait till spring...
>or later. :)
>