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Aftermarket cat affect A/F #'s

235 views 1 reply 2 participants last post by  Boost Junkie 
#1 ·
I was wondering if the RandomTechnologies HiFlo catalytic
converter distorts the wideband O2 readings from the DynoJet
tailpipe sniffer. Also, if it would affect/distort the readings from the 5wire sensor installed after the cat on the FJO unit? I would
prefer if someone a definitive answer but theories and "best guesses" are also greatly appreciated.
 
#2 ·
The after-cat temperatures won't bother the FJO unit. If the unit gets too hot, it will give you a message indicating same on the display, but that's unlikely to happen as the unit normally operates at a pretty high temperature because the heater keeps it there (I won't mention just how hot).

But aside from that, FJO does not recommend positioning the sensor after the cat because the cat MIGHT distort the AFR readings -- not saying that it WILL, but absent of testing to show otherwise, you should assume that it might. FJO has not conducted experimentation to determine just what, if any, the difference would be in before- and after-cat readings, but there are test results in the public domain recounting where the Bosch wideband sensor has been used in such experiments and shown to give wildly different readings before and after the cat. The safe thing is to put the sensor before the cat.

Steve - FJO dealer
 
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