I have an 02 5.4 L....and as of right now, the exhaust is mostly stock, with all four cats, but i removed/straight piped the muffler...it sounds good, but id like some more volume without spending money on exhaust systems...i have been considering cutting out two of the cats, but i have mixed reports on which ones to remove. Supposedly, you are messing with the O2 sensors no matter which ones you remove, but i have heard that sometimes you can avoid a CEL by removing the precats. Any Advice on which ones to remove would be greatly appreciated, and any experience with how that sounds would be greatly appreciated as well...thanks!

 

You may avoid a CEL with the front cats out, however you better be sure that you don't end up with a nasty leak afterwards, the only way to weld those right is to remove the downpipes to weld properly.

Removing the rears will gain you your volume, at the risk of inspection failing, leaks unless welded properly, and having a programmer to disable rear O2 monitoring, or the Gotts O2 modification will handle the CEL.

 

Pop out the rears. 50/50 on throwing a code. As stated above, gotts o2 mod or tuner will fix that problem, if it occurs.

 

Thank You! Luckily, we dont have such inspections here in SC, and the cops dont care about noise cause 5/10 trucks are rigged illegaly. Just wondering though...what is the volume difference from removing the front and rear cats? im looking for a middle ground, i want a decent gain...but not anything abnoxious...maybe thats being a little too picky but its worth a shot.

 

^ Not being picky at all. I spent a lot of money before settling on my current system. As far as the rear removal goes, it sounds like that is what your looking for in volume increase.

 

thanks, i appreciate it...i dont have the tools neccesary to handle this myself, so unfortunately ill be heading to the local muffler shop...and i dont know much about the gotts mods, but i suppose well cross that bridge when we come to it

 

You said it. Do a search on the gotts o2 mod sometime. Pretty easy.

 

will do man thanks a million

 

got the two rear cats out today...sounds incredible...and no CEL....operation was a success...thanks to you all!

 

Sweet deal man!

 

Glad to hear!