Originally posted by aekrot
how long would you expect a WB O2 to last in a race car running leaded C14 or C16?
1 year or 5 years (assume 50 passes per year)?
What is the common failure mode? (i.e. reads richer or leaner that it should? reads correct but 'slow', etc.)
Lead is only part of the problem, in a race car the engine specs are all looser, so oil is also passed along in the exhaust. The oil can be as if not more of a problem then the lead. Both coat the actual sensing element. And another reason to mount it somewhat downstream is so that at low engine speeds, ie crank, and first spinning up, the *oil* coagulates somewhat before traveling down the pipe, and possibly hitting the sensor.
Cold start enrichments are another WB killer. I've been kind of doing a survey, and it seems like well over 90% of the failures are reported at startup. Of the ones that I've seem die (normally from a poor heater design) they failed while driving. So it would seem somewhat logical that asking the sensor to go from ambient air temp to 850dC in 30 seconds, is kind of a tough job, now, emerse the sensor in an excessive amount of fuel and oil, while warming up, and it's life span will be shorter.
The most common failure is them just not working.
Seond is a false lean, which isn't too bad.
BUT, I have 3 that failed rich, which isn't good.
Slow, might be a matter of just minutes before failure, and some seem to last along time, just being slow.
