Will using race fuel for example C16 effect your O2 readings? I made a couple of passes with a mix of C16 and pump gas and I noticed my recorded O2 milivolts where far off what they normally would be though I know that's not what o2 sensors are ment to do I just want to know the effects of that fuel on them.

 

O2 sensors are "rated" for 50 hours of lead exposure. That would be based on a typical value for leaded fuel of 2-3grams/gallon TEL. C16 has 6grams/gallon TEL so its going to be tough on O2 sensors. But it should not cause immediate failure.

My car still has the OEM O2 sensors, mainly there to plug the holes in the headers. I don't use the stock PCM (and I run open loop), but the PCM is still there, and I can read the O2 sensors with my ScanMaster. After many gallons of straight C16 (and C16 + Air Race), one O2 sensor still appears to be putting out a rational numbers, the other one reads way low.

On the other hand, NGK makes what they call a "lead tolerant" O2 sensor, or something like that, and its suppose to stand up to twice the allowable exposure to leaded fuels. One of the magazines tested a pair when they first came out, and one of them failed IMMEDIATELY on exposure to leaded fuel. It was replaced, and then both of them apeared to perform correctly after exposure to lead.

 

Good info. Since you brought up the scanmaster, how exactly do you read the O2's with the numbers reading so fast?

 

The scanmaster will record the highest O2 reading after a WOT run, Thats probably what he meant.

 

My O2 voltages don't move "fast".... I run the engine open loop using an aftermarket ECU.

 

Denso 02 sensors are supposed to have a VERY high tolerance to leaded fuel use, due to their triple-filtration that does not allow lead to get to the platinum of the sensor.
I plan to run AV100LL in my new engine on the weekends and 93 unleaded during the week.