Re: S4 Sucks(according to some)

[Orin Eman <orin@wolfenet.com>]

> 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 it interesting 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.

Here is my take on the issue:

At WOT, they are dumping lots of extra fuel in to do two things, produce
more power and to keep temperatures down.  They calibrate how much at
the factory then the MUST ADD EXTRA to ensure they are safe ie. not too
hot.  This may take them past the optimimum mixture for power...

By monitoring the EGT, they can safely set the mixture for power,
stoich (their choice) and only dump the extra fuel in when necessary,
ie when the EGTs start getting high.

If they have chosen stoich, that just means that there is more power
available for the tuners... no complaints there.  If max power,
again, no complaints from me.

I would however suspect that the response time of the EGT sensor
won't be very fast (fast response requires a small thermocouple
which doesn't last too long; bigger more robust thermocouples
respond slower), so the control isn't going to be very accurate...
even so, it will be a lot better than the guesswork used in the past!

Orin.