Ok guys my 05 tahoe 5.3 has a cai and a magnaflow cat back. Ive been reading on here about several people that have a Y pipe on their exhaust. (Yes I read the sticky about bolt ons.) But what exactly does a Y pipe do and why would I need one?? Is it something that would be a part of the cat back system?? How would I know if I have one?? BTW my cat back is a single pass side exit. Thanks.

 

A Y pipe is exactly how it sounds, a pipe shaped like a y. It has two inlets to one outlet, or one inlet to two outlets. You dont need one unless you want to turn your single exhaust into dual exhaust, or if you add longtube headers and want to hook back into your stock location for the exhaust. You can also use an offroad Y pipe to eliminate the cat converters. You have one on the truck stock, it comes from the exhaust manifolds and contains the cats and joins the two manifolds to a single exhaust, unless you have a dual inlet/dual outlet muffler.Hope this doesnt confuse you more.

 

Thanks for the clarification. Thats what I was thinking but wasnt sure. If I was to use an offroad y pipe, how do you get around the O2 sensors at the cats?? Would there be anything to gain by doing this? At this time I have no plans for adding headers.

 

you shut the o2's off and either unhook them and have the PCM tuned to shut them off or just plug them into a simulator that makes the PCM think they are working.
Without running headers you won't really gain much by putting in an ORY. Headers are longer than factory manifolds and its easier to just run an ORY than to keep running o2's

 

thanks for the info