New Headers for my '04 S

[Stroked & Blown]

There are a couple hacks that I've seen to avoid the CEL on other vehicles.
The first one involves modifying a spark plug non-fouler to limit the amount of exhaust reaching the sensor:
http://www.energeticforum.com/renewable-energy/1387-o2-sensor-modification-using-spark-plug-non-foulers.html

http://forums.evolutionm.net/showthread.php?t=215795

Do the O2 sensors on the Box use standard threads? I assume they are std Bosch units.

The other option is to use an O2 simulator, but it looks like there aren't any available for Porsche yet: http://www.o2simulator.com/

[Topless]

Originally Posted by Stroked & Blown

There are a couple hacks that I've seen to avoid the CEL on other vehicles.
The first one involves modifying a spark plug non-fouler to limit the amount of exhaust reaching the sensor:
http://www.energeticforum.com/renewable-energy/1387-o2-sensor-modification-using-spark-plug-non-foulers.html

http://forums.evolutionm.net/showthread.php?t=215795

Do the O2 sensors on the Box use standard threads? I assume they are std Bosch units.

The other option is to use an O2 simulator, but it looks like there aren't any available for Porsche yet: http://www.o2simulator.com/

Surely you are joking right??
Never mind the CEL... If the primary O2 sensors are not in and working a Porsche will run like dog doo. Kinda defeats the purpose of adding headers don't you think?

[Stroked & Blown]

Is the CEL issue due to the fore (header/manifold) O2 sensor or aft?
The fore 02 controls closed loop fuel trims, the aft sensor tracks catalytic efficiency and has no bearing on fuel trims. If you remove the cat between the two O2 sensors, you can use the non-foulers on the aft sensor without a problem.

Is Porsche using the fore O2 for fuel trims AND precat efficiency?
If so, is this the case for all model years, or just 00-04?

[pacific986]

As to the sound vs. desnorkeling; I'd say the sound benefit from the desnokel seems to be the same and it seems like I hear it from the driver side vent not the exhaust pipe itself. I have EVO intake and no snorkel. The headers seemed to have changed the actual exhaust sound in a minor way, though I do hear a difference, and I do like it; though it is subtle. The actually throttle response seems to have improved a bit, especially at the low end. By that I mean it revs easier under load and at very low RPMs it is easier to modulate. That is what I notice more than the sight change in sound. Day 2 and I'm still happy with the upgrade.

After more research on this forum yesterday afternoon I found the link for the Durametric software. I think I will go that route if the CEL comes on.

[Topless]

Originally Posted by Stroked & Blown

Is the CEL issue due to the fore (header/manifold) O2 sensor or aft?
The fore 02 controls closed loop fuel trims, the aft sensor tracks catalytic efficiency and has no bearing on fuel trims. If you remove the cat between the two O2 sensors, you can use the non-foulers on the aft sensor without a problem.

Is Porsche using the fore O2 for fuel trims AND precat efficiency?
If so, is this the case for all model years, or just 00-04?

You would get multiple error codes if the primary (fore) and secondary (aft) O2 sensors were not reading exhaust gas. Once the car is warmed up the DME switches from a generic fuel map to a tuned fuel map based on information from the MAF, primary O2 sensors, air temp, engine temp, and driving style. Without primary O2 sensors in and working the DME gets confused and might get the tuning really wrong or just switch back to a generic fuel map which would lower performance and HP. The secondary O2 sensors are for emissions only.

On 2000 - 2004 cars the stock headers have O2 sensors before and after the first set of cats. Ignoring the primary O2 sensors and CEL just doesn't work. The car runs poorly. The trick is to add high flow cats, reprogram the DME to look for new exhaust gas values so it will be able to switch to a tuned fuel map again for max performance and HP. This is best done on a dyno by someone who knows these cars well like Farnbacher Loles. Now the car will run great and pass the Smog sniff test as long as no one looks under the car. Still not smog legal by the book. In California headers are legal on "track only" cars. I don't know of any simple backyard/shadetree/over the counter solution to this issue.

97-99 cars don't have this problem due to one set of cats only. Adding headers is a simple bolt on with no tuning issues. The DME sees normal O2 sensor values and selects a tuned performance fuel map after warmup. Still not legal on street cars in California.

[Jaxonalden]

Topless,

I have a question for about the O2 sensors. These headers have ports for the two sensors to screw back into. Obviously the primary sensor will read normal but the secondary will be off because of the elimination of the cat. What do you think the DME will think with that info?

[Topless]

Originally Posted by Jaxonalden

Topless,

I have a question for about the O2 sensors. These headers have ports for the two sensors to screw back into. Obviously the primary sensor will read normal but the secondary will be off because of the elimination of the cat. What do you think the DME will think with that info?

The secondary O2 sensors read emissions only and don't affect DME tuning. The best solution is to get them in the exhaust flow after a set of cats and eliminate all error codes. Some guys just mickey mouse zip tie the secondaries up under the car to eliminate a CEL. This works for a while. If something happens and the cats get fouled they will not know and engine damage can occur. See other posts where this happened ending in total engine loss. An expensive lesson in hot rodding.

[Jaxonalden]

UPDATE;

After numerous e-mails tiring explain my problem with the clearance issue and what I need done to the pipes, I think I've finally got my point across, in Chinese.

They said it will take a week and they will send me a picture. Will keep you all in the loop when the pics come in.