Pls no why etc questions I’m trying up figure something out ..

has anyone deleted the cats right after the manifold and how did you solve errors etc

mine could not be put back due to cats being bad..

 

You shouldn't have any codes if you just delete the front cats. The front o2 sensors don't monitor flow or lack of flow through a front cat. The rear cats and rear o2 sensors are the ones you have to worry about. The rears are emissions based, the fronts (wideband) control the air/fuel ratio.

This is how it works on ISF and most cars out there. Can't imagine it's any different on LS.

 

This is COMPLETELY wrong. On an IS350, ISF, GS460, GSF, LS460 it doesn't matter its basically the same, deleting the primary cats on the manifold will definitely throw a code, its the SECONDARY cats on the midpipe that can be deleted with no issues. THIS IS NOT UP FOR DEBATE.

You can live with the CEL, or try to find a tuner. RR racing might be able to fix the codes or have some 02 conditioners.

 

He’s talking about deleting the cats, not the 02 sensors. If the front cats are deleted, I don’t think it would necessarily throw a code...the rear cats actually have the O2 sensors built right into them, no?

I haven’t recently looked at the front cats on the LS460, but I imagine the O2 sensors would be placed upstream ahead of those cats (to adjust the air/fuel mixture) and the cats in the rear (with the O2’s right in them) would be the ones throwing a catalyst efficiency code if removed? Again, I could be wrong because I haven’t actually seen these front cats in a while and don’t remember exactly where they are in-line with the exhaust/O2 sensors.

 

Yes the CATS, that's what I said. I never said anything about deleting O2 sensors. Since you brought them up, why do you think Sikky or PPE offer O2 conditioners when you install their headers AND delete the primary cats? because the O2 conditioners will fool the sensors so you DON'T get the CEL. Without them you WILL get a CEL.

The rear o2 sensors come BEFORE the secondary cats. like 2 feet in front of them.

 

Na but I did a straight pipe though. I thought you weren’t suppose to take of cats or is that just a California thing?