[Diy_efi] Lead fuel compaible O2 sensor

[gary]

AFAIC, (not part of any race team) in today's race environment,
any race team attempting to determine AFR by means of EGT is
either not very serious about getting accurate measurements, or
has the time/budget to do necessary engine testing.  This would
exclude true pro race teams, as they accept the limited life of
WBO2 sensors when exposed to lead.  There IS a life, it is just
not as long.  We're not talking one sensor destroyed at a time
either, but 8 (8 cylinders) sensors at a time.  Not stating they
do not employ services of EGT as well, but their use would be
in a role of supplementing O2 sensors, not replacing them. On
their own, there are just too many variables that affect EGT.

Using the Bosch spec for the expected life span (of an a particular
WB sensor), with the use of unleaded fuel in an OEM application,
of 60,000 mi/97,000  km, as a gauge, comparos can be made.

Adding .15 g/ltr. of lead reduces the life to 60,000 km.
Adding .6 g/ltr. of lead reduces the life to 20,000 km.
I understand 100LL AVGAS has a lead content of .56 g/l.

We can put this length (mi/km) lifespan in perspective, by converting
it to time.  Typical long term average speed of a vehicle in regular
(street) use would be ~ 50 km/hr.  Using .6 g/l lead as an example,
avg. lifespan would be 400 hours.  What would be the avg. speed
for any given race vehicle application/class?  Figure accordingly.

My info (obtained from WB sensor forum discussion), state lead
concentration varies from 1.12 -1.6 g/l in common/popular leaded
race fuels used.  Degree of deterioration of sensors exposed to
lead, is not 'linear'.  IOW, doubling the amount of lead in the fuel,
will not shorten the sensor life by ?.

Rest assured, WB O2 sensors are DEFINITELY used for race
vehicle tuning.  Again, depends on how serious or knowledgeable
any given team is.

GAS


----- Original Message ----- 
From: "Phillip Kuhn" <pmkls1 at yahoo.com>
To: <donsauman at cythera.net>; <diy_efi at diy-efi.org>
Sent: Saturday, July 02, 2005 10:26 PM
Subject: Re: [Diy_efi] Lead fuel compaible O2 sensor


> As far as I know there is no such thing, ususally on cars
> that run leaded fuel, such as race cars, they will use
> exhaust temp sensors to monitor a/f ratios.  Somebody
> else may know more about that that me though....