Questions about headers and bypass

[schoir]

Originally Posted by root_werks

This is interesting reading.

My 97' pulled a CEL for failing cat (P0430). I was going to purchase both, but didn't realize they have 4 cats? I'd have to stick my head under there again, but I think I've seen only the 2 cats with an O2 before and after each cat.

Am I wrong here? I would think cat bypass pipes would throw CEL's all over.

Your '97 only has 2 cats total. One on the left and one on the right.

The cats are located in between the headers (a/k/a exhaust manifold if it's stock) and the rear muffler.

The '97 has a total of 4 O2 sensors, and they are located on the cat pipe, just before and just after the cat.

Here is a photo of the right side stock header (exhaust manifold) on a '97:





Here is a photo of a Billy Boat header installed on the right side:





Here is a photo before the muffler installation, showing the headers installed with the stock cats for a '97. The red arrows point to the O2 sensors at the rear of the cats. The front O2 sensors are not visible here, but are at the front of the cats:





Do not take the caution about the exhaust manifold bolt heads snapping off when trying to remove the stock exhaust manifold from the head lightly:

http://www.ppbb.com/phorum/read.php?19,1552140,1552140#msg-1552140

Regards, Maurice.