Hi,

In the instructions for my Wideband lambda kit (LM-2), It says that the labmda probe needs to be place before the CAT to get accurate readings. I have noticed that dyno operators usually place a lambda in the tail pipe which would be post CAT and the readings seem accurate. I'm just wondering how much difference this makes?

I have a lambda hole post CAT that I can use. I would have to drill a new hole to place it pre CAT. I'm just wondering if it is worth it?

Thanks

 

From what i understand it would need to go precat as if the cars over fueling any/most unburnt fuel would be burnt off as it flows through the cat. Could be wrong tho but would think precat would give the most accurate result.

 

^ Correct. If you want to fit the wb temporarily you can always pull your stock narrowband sensor and fit the other one there. Longer term, if you want both fitted permanently, just open a hole in the DP and weld a second boss in.

 

Cheers guys

In that case i'll leave it for now as I wanted to monitor the AFR in closed loop mode and i'm going to switch to a different ECU soon which uses a wideband lambda input so I don't really want to drill a new hole.

Just out of interest, how do mappers get round this when mapping cat'ed car? Do they swap out the narrow band sensor or just make do with inaccurate readings

 

Akuma Testing, Chapter 1:Wideband Readings - NASIOC

 

Perfect, thanks