I'm wondering if anyone has installed a wideband and is using the 02 sensor in the stock SVT cat?

I'm doing the SVT header conversion on my car which has an AEM wideband/Tom's tune and after looking at my dad's SVTF, its looks almost impossible to weld in an O2 bung on a stock SVT cat near the first O2 sensor. The only way I see doing it is to grind off a heatshield bung and drill an O2 bung hole in its spot making sure that the sensor would angle away from the oil pan/windage tray. But this leads me to my next question, if I put the O2 in that spot then it would be just out of the exhaust stream. Would this affect the readings my wideband gives me?

I've thought about putting it into the collector of the header but it wouldn't read quite right because it'd only be reading from 2 cylinders, not all 4 like it should. Also I need to pass emmissions so there is no gutting the cat and using the rear O2 hole.

So what have all you guys who've installed widebands on a stock SVT do? I'd very much appreciate it if someone had pics of their setup! [ffrocks]

No ones installed a wideband on a stock SVT cat. conv. before?!?!?!

I did not put mine in cat---I placed the O2 sensor in the collector of the header

Didn't see this thread before. You can't weld an additional bung into the stock cat (or at least, I wouldn't want to try). If you put the wideband in the rear O2 slot, it won't read right because it will be measuring the catalyzed exhaust. The best spot is the header collector.

Didn't see this thread before. You can't weld an additional bung into the stock cat (or at least, I wouldn't want to try). If you put the wideband in the rear O2 slot, it won't read right because it will be measuring the catalyzed exhaust. The best spot is the header collector.

I'm curious as to why you wouldn't weld on the stock cat?

The reason I didnt want to put it in the header is because there looks to be kinda of a splitter in the collecter. With that there, I'm afraid the O2 is just going to read off two cylinders, not all four equally.

Well I mocked up everything last weekend and after finding out I bought a bent header [:(!] (was able to bend it back without problems), it looks like I can put my Wideband O2 right next to the first O2 without having to grind anything while clearing the oil pan/windage tray. I think I'll go that route and when I get it done, I'll update this thread with pics.

Thanks for the replies.

Who cares it its catalyzed or not? When they tune your car they put the o2 sensor in the exhaust tip, regardless if you have a cat or not. I have mine after the stock cat on an SVT

Who cares it its catalyzed or not? When they tune your car they put the o2 sensor in the exhaust tip, regardless if you have a cat or not. I have mine after the stock cat on an SVT

And this works well for you? what are your a/f ratio numbers in the rpm band? I was debating whether to do this or not with a cat, and placing the wideband after the cat.... but to think about it, the air does get filtered, most likely changing the air/fuel ratio going out.

It works fine. Think of it this way, How could u ever tune a car in Cali if that made a difference? They have to have cats in place by law. Closed loops O2 sensors work with a cat. Both Fernando and Tom from focus power said OK. Catalysts dont affect the af #'s just the CO, NOx and HC emissions. Cats are actually designed to work with different a/f ratios to reduce different emissions based on the level of stoichiometry level of the exhaust gasses produced. Make sense?

According to Tom, a cat will change the AFR reading...he will still tune you based on your AFR gauge readings, but he says that they are slightly off.