WB O2 and EGT compensation

[Brian L Massey]

On Sun, 24 Oct 1999 16:43:44 -0400 "Bruce" <nacelp at bright.net> writes:
> 
> If you'd care to read the archives some there is data aready there 
> about
> this devise.  BTW, it uses the same sensor as the DIY unit.  So they 
> have
> the same sources for error, as a function of the actual sensor's 
> design,
> the temerature *error* will/could be thought of as the EGT has 
> raised the
> sensor temp higher then it's operating temp..  Yes, there is some 
> variance
> from post to pre turbo, but since the proper tuning is what AFR for 
> best
> performace (as opposed to tuning to get a specific AFR), the *error* 
> is
> mute.

Ahh, good point. I finally got the SAE article about 2wks ago that NTK
published on their 5-wire sensor technology back in 1992 IIRC (same art.
that is mentioned in the archives, but I'm at work now, so don't have it
in front of me), and as was also discussed in the archives long ago, if
you believe them, there is maybe more sensitivity to pressure than to
temperature, as long as you stay within IIRC 600-900C. From the article
graphs, it appears the heater is able to hold up the lower end of that
range, so an EGT might be useful to make sure you don't go above it,
especially if you are pre-turbo.

The heater would be inputting less heat as the local EGTs rose (kind of
self-compensating, because the heater resistance rises with temp), so
even though you would not know exactly what the sensor temps were, you
know you're getting towards the sensor limits if the EGT itself
approaches 900C. Put another way, EGT probing might help you pick a safe
spot in your headers, although just looking at the pipe colors might be
just as good; either one is a bit circular however (since state of tune
effects EGT of course). Any further thoughts?

Brian
________________________________________________________________
GET INTERNET ACCESS FROM JUNO!
Juno offers FREE or PREMIUM Internet access for less!
Join Juno today!  For your FREE software, visit:
http://dl.www.juno.com/get/web/.
----------------------------------------------------------------------------
To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes)
in the body of a message (not the subject) to majordomo at lists.diy-efi.org