I have a wideband o2 sensor for my DFI. My turbo kit only has one bung for the O2 and its in the downpipe. Shouldn't the O2 sensor go before the turbo in the headers? Won't it read diferently before the turbo? compared to after the turbo?

 

Wideband sensors can overheat if put upstream of the turbo. You're better off putting it after the turbo. The readings would be the same if the sensor could last upstream of the turbo, as there's no chemical changes until you get to a catalytic converter or air injection pump.

 

Thank you, thats all I wanted to know. I kind of figured that but I wasn't too sure.

 

I'll have to disagree on this one. There are significant temperature and pressure differences in the header vs. downpipe, and both Bosch and NTK publish specifications on their sensors that show the relationship between these two factors and measured AFR. The difference is not negligible.

Many factory turbo cars have sensors in the header, but the wideband sensors used in the aftermarket are not designed to operate under those conditions.

 

Agreed. Isn't there a multiplier used based on the backpressure if you have it upstream of the turbine?

 

Good call on that, Craig. I should have said "The readings would be the same if the sensor could work properly upstream of the turbo."

 

I am talking about your typical bosch sensor, not a NTK. I don't think it will hold up in front of the turbo

 

Craig is correct. I've seen the charts and the measurement error is substantial at the higher pressures upstream of the turbo.

-Chris

 

the correct placement would be in front of the turbo. Is that what you are telling me?

 

After the turbo, 6-12" downstream.

 

K I have it in the right spot then! LOL