EGOR - how is he under PRESSURE?

[garfield at pilgrimhouse.com]

On Wed, 03 Jun 1998 00:28:50 PDT, "Patience Challenged"
<expert_not at hotmail.com> wrote:

>Be very carefull here about WOT exhaust pressure - turbos can easily 
>have twice the exhaust back pressure at the cylinder of the boost 
>pressure and can have very significant pressure all the way thru the 
>system.
>
>...expect about 30 PSI on a 15 pound
>boost normal installation.

Sheeeeeeeeit. 30psi? arrr arr arrrroooooo. See that's why we gotta sum
the fractional wits on stuff like this. I had NO idea it could be that
high.

>YMMV and it may not be relevant if EGOR is only sitting at the tip as a 
>shop measurement tool and not part of any turbo engine management 
>system.

Yeahbutt, yeahbutt, O2 sensors normally CAIN'T just sit on some tip of
something, they gotsta be in the exhaust flow fairly near the belching
dragoon. This was Brock's quandry; how on earth can you use these
commercial boxes as a simple meter, and just stick the sensor element in
a bung, when they have no way of compensating for back pressure effects
on the sensor. Finofino for Eng.Mgmt., cuz like the NTK/SAE paper
suggests, just do a rough approx. for what the backpressure is likely to
be, given the things the ECM knows, namely MAP, RPM, etc. It's just
volume forced thru a restriction; not rocket science to get a rough
idea, assuming you no how restrictive your exhaust system is to begin
with.

But the real puzzle that begs to be answered is why the Horiba, NTK, ECM
boxes don't even MENTION this issue in their user's manuals or
literature!!

>Little ION question.  When its all working, will we be able to get 
>enough information to adapt it to a diode stack so that it can be used 
>without throwing away the electronic ignition and coils we already are 
>using?  Some of us might prefer to retain what we have.

I think so. I intend trying some of those eXperiments as well,  just not
at first (ya know, tryna stick as close to the
known-good-existence-proof SAAB implementation, and keep the number of
unknowns to a minimum). I've already got some experience using the HV
diode stacks, and there's at least one good patent (5,293,129: guys from
Mitsubishi) that shows all kinds of configs where you use HV diodes to
keep from intruding into the coil secondary wiring. That paper even
shows how to do it whilst using wasteFire coils IN wasteFire mode.

So many eXperiments, so little time. B)

Herr Dr. Garfensteen