Marine Blue

Looks like the cats are built into the headers, hard to tell for sure but that's how it looks.

orthojoe

My info came from a post that Gert from carnewal made a while back:
https://rennlist.com/forums/10119973-post25.html

This is the thread:
https://rennlist.com/forums/987-981-...nd-louder.html

Rob, what are you planning to do with this info? Just curious...

RobSpyder

Having the PSE reinstalled as we speak and was sad about gaining another set of cats...sounds like that's not the case. Also, I want to go aftermarket headers mated to the PSE mufflers and see how that works. Extra cats in the PSE mufflers would sort of nullify any gains from the headers.

987s987

I would say that the round coffee can sized part to the right is a 500 Cell cat. That would be what you want to remove. It is what the aftermarket exhausts delete for performance improvement and deeper sound.

terbiumactivated

I'd rather listen to a Porsche all day long over a short pipe Sportster or worse yet every ******* with a subwoofer and big amp

orthojoe

If you mess with that cat, you will very likely trigger a CEL light, even if it's a high flow 100 cell cat. There are ways around triggering the light, but questionable if it's worth the hassle for the power increase that will barely be noticeable. These aren't turbocharged cars.

RobSpyder

Picked up the car today. PSE installed. I'm quite satisfied with the results. It now lacks the utter madness of volume from the race exhaust, but it's soooooo much more livable. Tone above 5k Rpms sounds great without deafening drone from 2-3k.

In the end, the spyder is about weight and handling, not showcasing a (sadly) rather mediocre engine output.

I'll leave the mouth gaping tone to the DBS.

987s987

Joe, This is the exhaust he's tearing apart not the headers. All aftermarket exhausts have pretty much done away with the cat completely for performance and sound improvement. All 4 O2 sensors are on the headers themselves, which he isn't modifying. You should be able to run open headers without throwing a CEL for O2...although I wouldn't recommend that. It would surely **** off your neighbors.

orthojoe

We might be on different pages here. 987.2s do not have Cats inside the exhaust system. Vendors have been claiming for years that an aftermarket exhaust removes the secondary cats based on the 987.1. It wasnt until Gert opened up the 987.2 exhaust that he found there is NO secondary cat in the exhuast on 987.2s. None of the prior vendors bothered to confirm their claims and just assumed that 987.1 and 987.2 were the same, which they are apparently not.

I'm not sure what you mean by open headers, but if look at the diagram, the catalytic converter lies just past the headers and there's a sensor before and after the cat. If you just change the headers, then you'll be ok. However, it looks like the headers are integrated into the catalytic converter, so you can't seperate the 2. If you change the cat by either removing it or placing a high flow type, you will likely trigger the CEL light unless you run o2 spacers or modify the ECU. If you look at the fabspeed 'race header', the cat is eliminated, and they themselves say that you will trigger a CEL unless you run o2 spacers. I've run o2 spacers in the past and even they are not fool proof to get rid of CEL lights.

RobSpyder

Thanks guys. I will probably just leave it stock. If I did headers, I would go high flow cat and softronics tune to remove any potential CEL. It sounds like it won't make a world of difference though, so is likely not worth the effort/cost.

987s987

I suppose I could be wrong on the 987.2 and whether it has cats in the exhaust itself. I know on my 987.1 there are cats built directly into the headers themselves with an O2 sensor before and after the cat. Obviously the ECU reads the amount of O2 before the cat and after to determine whether the car is releasing the prescribed emissions, and adjusts for leaner/richer fuel mixture, right? After that sensor, one should be able to put whatever exhaust they desire. That's what I meant by open headers...open stock headers. Certainly back pressure would vary from just straight pipes, to a very restrictive exhaust. Neither should trigger a CEL from the O2 sensor as the gases have already passed the final sensor. I'm certainly no expert on these cars as I've only had mine about a year but overall, I have a very good understanding of engines and mechanics. Wasn't trying to call you out, just trying to get the right info out there. If changing the exhaust doesn't cause a CEL, why would modifying it?

orthojoe There are no secondary cats in the 987.2s. They only exist in the 987.1s.
Despite what many vendors advertise, an aftermarket exhaust on a 987.2 does not remove a secondary cat. This is the reason why 987.2 exhausts are not as loud as 987.1s

Shouldn't this be the opposite? If the 987.2 has 2 less cats, it would have less restriction and thus be louder not quieter.

orthojoe

This is correct. the 987.2 cats are built into the headers as well, so any modifications made after that would not have any effect on CEL lights. Some vendors make a header which eliminates the cat or places a high flow cat in the headers. I thought this is what you meant by open header setup. This is type of setup is at risk for getting CELs.

Your logic is correct, but reference point is incorrect. We are talking about replacing the exhaust with an aftermarket one and subsequent volume increase as a result.
If the 987.1 has a cat in the exhaust and you replace it with an aftermarket one that does not have a cat, there should be a larger change in volume for that system than replacing the exhaust on a 987.2 that never had a cat to begin with.

987s987

Well explained Joe. That would leave me to believe that either the stock 987.2 is either louder than the stock 987.1, or the 987.2 has a more restrictive cat in the header. Forgive me, this isn't my first sports car but it is my first Porsche. I'm learning on these forums every day.

Your logic is correct, but reference point is incorrect. We are talking about replacing the exhaust with an aftermarket one and subsequent volume increase as a result.
If the 987.1 has a cat in the exhaust and you replace it with an aftermarket one that does not have a cat, there should be a larger change in volume for that system than replacing the exhaust on a 987.2 that never had a cat to begin with.[/QUOTE]

orthojoe

No worries, man. I think your assumptions above are correct as well. I know you're competent. Our point of references were just different, which is why I thought we were on the wrong page. We're all learning from each other. That's what the forum is for.

the_vetman

I think there's a slight misunderstanding here.

FYI:

987.1: 4 cats (catalytic converters). 2 cats in headers, 2 cats in "catback" exhaust. When you get an AM catback exhaust, you get rid of 2 redundant cats.
987.2: no cats in catback exhaust. AFAIK still just 2 cats in headers (one on each side).

Why 987.2 sounds quieter: DFI engine!

High-flow sport cats: (usually) 200 cell cats made in Germany (if a respectable brand). These sport cats are in the headers. No CEL.
Stock headers: 400 cell cats. No CEL.
Catless/racing headers: no cats at all in the headers, least restrictive. CEL unless you get an ECU tune (e.g. Softronic, EVOMSit) or play with O2 sensors.
Racing headers are also broken down into short- and long-tube headers. Long-tube headers give a bit more hp at the top end of RPM. More grunt & torque down low with short-tube headers.
AM headers: good for increasing mid-range "useful" torque.

HTH!