From: hotrod@dixie.com (The Hotrod List)
Subject: oxy sensors
Date: Wed, 06 Jan 93 04:13:35 GMT
Organization: Dixie Communications Public Access.  The Mouth of the South.
To: hotrod@dixie.com
Reply-To: hotrod@dixie.com
Posted-Date: Tuesday, Jan 05 23:13:18
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	All of this talk about O2 sensors has me wondering...
	Is there a sensor i can get for my application?

I am in process of setting up a 454 chevy with hildeborn fuel injection 
for drag racing. The intake has seperate runners for each port. My thoughts
have me pondering the use an O2 sensor per port to determine the rich/lean
state for each cylander. 

I'm not running unleaded gas, but the stuff from the racetrack which has a 
high lead content. This type of gas (vp c-12) takes a long time to show signs 
on the plugs (I guess it has to do with the burning of almost all the gas and 
lack of the crap that makes the plugs black in the first place.)

I don't have a problem with modifying my headers (which cost $550.00),
Re-programming a computer to monitor each cyl., and writing software to be
useful for me (just as it is for all you EFI re-programmers) to determine
how much to modify air/fuel ratios before each race.

I see this capability helping me (and every other racer using 
Mechanical Fuel Injection) as a tuning aid, warning device, and engine 
saver...

[You absolutely will have to use unleaded gas with these sensors.  No
way around it.  It's the same platinum on the sensor that gets poisoned
as in a cat converter.  JGD]

Now here is where i got the idea... On the top fuel/Funny Cars,
they have a sensor in each exhaust port.(I know... they don't use gas)

Are they using this sensor 
A). to measure heat given off from each cyl?
B). To do what I just described?

You tell Me(and the list). I'm not sure why the top teams use these sensors, 
since I don't know any to ask.

	My question is: Where can i get a sensor for my application?

Anyone have any other/different suggestions for using a computer for optimum 
engine tuning?

-dan a.
dhoward@sw.stratus.com

[Those sensors are simply thermocouples that monitor temperature.  The most
common drag racing computer in use is the Race Pack from a company owned
by Kenny Bernstein.  I have one of the units here in my lab to evaluate.
I'll have to say that I'm terribly disappointed with the unit.  For 
example, the thermocouples are not cold junction compensated.  Worse,
the cold junction is in that little aluminum box that the thermocouples
come together in that is mounted near the headers.  I was out at 
Gary Smith's (owns Atlanta Dragway, runs a ProStock car) shop looking
at some printouts from his unit.  Cylinder temperature varied 500 degrees.
That is, of course, horrible.  When I mentioned that to him, he said
that was typical and they just hoped that changes to the readings 
represented what was happening and that mostly no one pays any 
attention to the reading.  Wish I could drop $8000 and then ignore
the results!  

Anyway, what the pros look at is the engine RPM, clutch RPM and tire 
RPM during the run.  These should be fairly accurate since variable
reluctor pickups are used.  There are typically also inputs for 
G, fuel pressure, oil pressure, air temperature, barometric pressure
and a few other things but I highly question the accuracy of any of these
since there is no calibration capability.

In your case, I'd look at exhaust temperature, trying to achieve 
uniformity and trying to correlate good ETs with temperature.  I'd
also look at engine and clutch RPM and Gs.  An outfit called 
Race Performance Measurement - RPM - makes a nice little $2000 
data acquisition box.  I don't have a number handy but they advertise in
most motorsports magazines.  JGD]

----------
Posted by: Dan Howard <emory!cam2.sw.stratus.com!dhoward>
Newsgroups: alt.hotrod,wiz.hotrod