My truck has si/so cat (late 99 production)

 

Ah, that makes things different.... There is a thread in the faq section that shows exhaust layouts, including pipe sizes. Only thing that changed is really the cat, and some of the pipe on either side of it. You may still be able to use the OR y-pipe. Have a look.

 

that Jegs Y-pipe says its for a 94-99, all V6 and V8 engines. those had the DI/SO cat. They do not list a product for 00-01.

at a glance, i can't see any reason why it wouldn't also work on the 00-01, which had a slightly different OE front pipe, and the SI/SO cat. i don't think the exhaust manifolds are any different, and i don't think the muffler is any different, so i guess the only question would be the OE cat hanger bracket.

another way to check would be to see if the high dollar cat replacements vary in year. if they cover 94-00 then there can't be any differences.

 

The Maggy "Y" is very high flowing, stainless and at $25 about everywhere - it's cheap...

I've got a ported TB, LT headers, my original cats moved back about 14" to make room for the headers/collectors and a "Y" that I had my local shop fab up. It's not quite as free flowing as the Maggy, isn't stainess and they charged me more to make it ($35) than the Maggy, but it's a LOT better than the factory POS.

 

ok after looking again the jegs off road pipe looks loike it will be fine, I could not visualize it from the desk.

I put my headers in then add new y pipe add new o2 sensors and say leave the cat off for a while, will the o2 sensors be ok? will it toss a code?

Do I even really need to replace them?

 

May get a cat efficiency code. Just do the non-fouler trick on the rear O2.

How old are your O2's? If you have more than 80K miles on 'em, wouldn't hurt to replace. Rock Auto has 'em cheap. (NTK or Denso please.)

 

well its a 99 with 147k on it, never been changed neither has the cat......

 

Replace them.

 

at the risk of sounding like an ID10T the listings are for left or up stream or down stream. All of my stuff is on the right side so do I go with up streem and down streem?

Ok found an up stream right I am guessing there is only 1 down streem?