when i had my zeitronix gauge installed, the instructions said install the a/f sensor before the cats, but my installer said it would take much longer/more money to install it in the header than after the cats, so i had them install it after the cats. now, my a/f at idle and anything less than positive boost reads around 14.7, which i know is normal for idle only.
so my question is has anyone else done this, and how do you know whether or not you are lean?
btw, my post-sc-install a/f dyno reading was appropriately rich, btwn 11-12.

 

i installed my a/f sensor on the cat piping itself, right next to the flange, just after the header. I peeled back some of the aluminium sheilding & had the bung welded in.
Under normal driving my a/f bobbles around 14.7. I installed ny zeitronix a few weeks before my supercharger to see what the stock engine would read. Same basic numbers. Only under WOT does my a/f drop down low.

 

ya, you would not get a correct reading after the cats. do what bailey did or get a set of test pipes and have it welded in those.

 

good ideas guys. thanx!