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.

[root_werks]

Great pictures thank you! That's pretty much what I thought after doing a little more reading up on things. Actually makes putting headers on the 2.5 an easier task than 2.7's and up I guess?

This is turning into a good informational thread on the differences between the early and later Boxsters.

[ChrisZang]

Originally Posted by Stunin_Stud

So technically I can play it safe keep the stock headers and get the bypass for 500 bucks and a muffler and get no CEL and still get a nice sound. how much of a difference in sound or power would headers make? I feel like the headers are all the same and the ones that are not are way to expensive and the power claims seem exaggerated.

Can't talk about the headers, but here's the breakdown for exhaust and bypass:
I have a modded exhaust (no droning and great sound) and added the bypass pipes later
I would say that the exhaust makes 90% of the better sound and the bypass pipes 10% (when reved over 3,500 RPM).

I see you're in San Jose, I work in Santa Clara, let me know if you want to listen to my setup

Edit: Reading your signature I'd guess we already met before

[Stunin_Stud]

Thanks I may get in touch with you to check out your car. Im currently in the caribbean.

[ChrisZang]

Originally Posted by Stunin_Stud

Thanks I may get in touch with you to check out your car. Im currently in the caribbean.

Cool, which island?
I've been to Saba a lot in the last 3 years (like 20 times or so)

[Boxtaboy]

Was thinking about doing the Fabspeed cat bypass pipes on my 01, which has both primary and secondary set of cats. Wondering though- if I get rid of the cats in the rear section and replace with the Fabspeed Cat Bypass pipes, since there are a set of 02 sensors in the rear section as well, wouldn't that set off a CEL light if removed?

[ChrisZang]

Originally Posted by Boxtaboy

Was thinking about doing the Fabspeed cat bypass pipes on my 01, which has both primary and secondary set of cats. Wondering though- if I get rid of the cats in the rear section and replace with the Fabspeed Cat Bypass pipes, since there are a set of 02 sensors in the rear section as well, wouldn't that set off a CEL light if removed?

take a look at where your O2 sensors are and where the cats are on your car and then you have your answer...

[jwade]

Originally Posted by Boxtaboy

Was thinking about doing the Fabspeed cat bypass pipes on my 01, which has both primary and secondary set of cats. Wondering though- if I get rid of the cats in the rear section and replace with the Fabspeed Cat Bypass pipes, since there are a set of 02 sensors in the rear section as well, wouldn't that set off a CEL light if removed?

No it won't set off a CEL if you remove the rear cats and replace with Fabspeed by-pass pipes.

You won't regret your purchase either!!!

[Stunin_Stud]

Originally Posted by ChrisZang

Cool, which island?
I've been to Saba a lot in the last 3 years (like 20 times or so)

Im in Dominica. Im trying to plan out my projects so when I come back to San Jose I can put everything together at once. I currently have the 2003 euro rear bumper being painted along with center console and speedster humps.

[Johnny Danger]

I experimented with several different exhaust configurations before choosing the final system for my 3.2 S. I found the following set-up produced the best results in terms of performance and reliability (keeping my vehicle OBD II compliant).
Here's my ditty:

1. A less restrictive, high quality after -market cat back exhaust.
2. By-passing/deleting the secondary cats (they're like having an extra set of thumbs).
3. Headers and cats that stick with the basic principles of the oem design, however, they incorporate longer, equal length primaries that flow into a merge collector, along with lower cell - high flow cats (something on the order of HJS 200 cell).

No need to relocate O2 sensors, make bungs, chase CEL's, reprogram the ECU, or worry about emissions ! Excellent results in terms of improved power and performance. And perhaps equally important - great sound !

[eightsandaces]

what about the fabled (perhaps 100% true) notion that these cars need back pressure? I was looking at sport cats and asking around, one guy said he wished he has purchased the 200 cell vs the 100 cell for the back pressure, what't the experience of the header owners??