# Wideband O2... **URL:** https://forums.speedlife.net/t/wideband-o2/104735 **Category:** SON240sx Automotive **Created:** [March 21, 2007, 9:46am UTC](https://forums.speedlife.net/t/wideband-o2/104735 "2007-03-21T09:46:58Z") **Posts on this page:** 1 **Showing post:** 10
### Author: ![Jedi\_Car\_Fan](https://avatars.discourse-cdn.com/v4/letter/j/b9e5f3/32.png) [@Jedi\_Car\_Fan](https://forums.speedlife.net/u/Jedi_Car_Fan) #### Post date: [March 22, 2007, 5:52am UTC](https://forums.speedlife.net/t/wideband-o2/104735/10 "2007-03-22T05:52:00Z")
> [@carlisle \> \*](https://forums.speedlife.net/t/carlisle/11710/227): > > heres something i’ve always wondered… how the hell does the wideband in the tailpipe work for tuning on a dyno if you have a cat? an O2 sensor just measures the amount of oxygen in the exhaust, but the cat uses up the O2 when it converts the exhaust gases so if my thinking is correct it would throw the reading waaaaaayyy off. I was thinking the same thing because even in the manual for my zeitronix unit it clear states (place probe 12’’ away from turbo BUT BEFORE the cat to ensure a proper reading). So I as well was wondering how much the reading changes with the probe stuck in the end of the exhaust etc etc --- _[View the full topic](https://forums.speedlife.net/t/wideband-o2/104735)._