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?? :confused:
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?

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?

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.

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.

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.

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. :cool:

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. :)

headers update
 

After adding headers and tying up the second set of O2 sensors on my 2000 Box S, the inevitable has happened. CEL, P-codes are 0139, 0159, 0156, and 0153. Essentially, because the second set of sensors never warms up, the DME isn't happy. The car runs fine and has a nice chunk of additional power through the mid range. Burns a bit more fuel, though :D .I've hollowed out the second set of cats, so I'm not concerned about those clogging and fouling, and the car is primarily for AX/spirited driving, so I'm fine clearing CEL's every now and then and getting along with it. I will be saving some cash to have the ECU remapped to make the most of things, though.
Cheers!

J.fro,

What was the reason for tying up the second set of O2 sensors? Didn't your headers come with a second set of ports to screw them into?

i might have a solution! I'm never seen it doen on Porsche but tuner cars
we buy a washer and screw it in along the o2 sensor.

-o2 sensor is still in and detecting
-bring the sensors higher that way it is not detecting as much exhaust fumes

it worked on many cars not sure this one
but i mean washer is like less than $1-2
why not give it a try

if it's done, let me know if it works

Steve

My headers do have the second set of 02 bungs, but from what I understand, the purpose of the second set of sensors is to detect catalytic converter efficiency. Being in the exhaust flow but without the cats, they measure that the exhaust gases are the same as the first set and send an error code that the cats aren't working. I'll be installing them this evening to see if the result is different.

"I have not failed. I have discovered 1000 ways that don't work". T. Edison

i have eliminate all 4 of my cats...

headers with all 4 o2 sensor plugged in and straight pipe and borla exhaust
no CEL, one thing I do not like is that it's too annoying loud...
sound like a muscle car :D

so I'm going to put the secondary cat back to see how it sounds like...

Jeffrey, how does your exhaust sound like with headers and bored out secondary cat??

I can't wait to get my modified header so I can play with my O2 sensors like you guys. :rolleyes:

I think I'll just plug my sensors in and see what happens. I know J.fro said he tied his up to prevent a CEL but without them sensing something they will throw a light, no doubt. I like the washer thing as long as part of the sensing ports on the O2 sensor is out of the exhaust stream. Time will tell after I have them installed and I get a CEL.

You guys still havent answered the question how headers compare with the overall performance/sound compared to desnorkling... :p

Desnorkling= swimming in a pool
Headers= swimming in the ocean

How's that for an analogy?

Cel
 

Car threw a CEL after 250 mile ocean swim. No worries. I'll just delete it w/ the Durametric software.

j.fro wow didnt think it was that big of a difference lol. I mean i felt a pretty nice bump after densorkle but might have to try headers if its swimming in a ocean!

Remember guys, the engine is a big air pump and the more efficiently you can draw the air in and blow it out the more power you'll make.

That’s why opening up (desnorkeling) the air intake, installing a low restrictive air filter, adding a turbocharger, supercharging are great ways to increase the intake volume. The same can be said about headers, there're less restrictive than stock and that compliments the scavenging of the cylinder to make way for the next charge. But not as much as to burn valves by not providing the proper back pressure.

Nitrous Oxide, now that's a different animal and doesn’t follow this line of thinking.

The headers really woke the engine up, especially from 3000-6000. However, I already had better flow from modified cats and the muffler, and a less restrictive intake system (including the desnork). But, like the ocean, I'm finding that you can get into much deeper trouble. I'm chasing a CEL, but I've got a couple of things in the works... we'll see how it goes.

Caution on those headers...
 

I too bought a set of the $100 headers from eBay, no idea if they are from China or wherever as they all look the same, packaged the same etc. Nice looking when they arrive.

Removed my old with no exceptional difficulty, pressed out the four studs on my vice with the old over-sized socket trick, again no problems.

Installed first header - problems. After two days of dicking around I have found the screw holes are badly misaligned, and no way can these be installed as arrived. Using as a template the old gasket and/or the old manifold, the holes are way off.

The bad news is this causes the new bolts to cross thread, and the aluminum heads are so soft that even finger tight at first is enough to bugger a thread - then you're in for some work. I have had to redress four holes of threads, and I only used my fingers to spin the bolts. The misaligned holes on the new headers drove the bolts at a bad angle, and working under the car it's too tough to see perfectly.

The flange can indeed be drilled and made right, so this is not the end of the world. I'm just saying that when you buy some of these first of all be prepared (tool-wise) to drill if needed, then step one compare your old gasket to the new flange before going any further.

I'm not finished yet, but I hope I won't have any more bad reports!

Finished
 

OK - job is done.

Installed and removed four time each side for fitting and drilling. What a pain! Some holes were off by as much as 1/4inch. The other flange with three holes lined up fine.

When/if I ever have to get involved in there again I'll be looking at some heliocoils to keep things strong. Not a good situation, and again I was stripping the first few threads just with my fingers - that is some soft material!

I assume the five hundred dollar headers are perfect, and hey maybe so are every other set of one hundred dollar headers, and I just got the bad one. But I'm telling you check first before against your stock gasket before you start installing.

Kevfra, which eBay vendor did you get your headers from? Just curious of which vendors are selling the versions with the fitment problems... While they all look pretty much the same, seems like some people are having fitment issues like yours, and some people are not reporting any problems with fit at all...

I bought from tuningpros in California, but I can't knock them. Their service was great, shipping immediate, price best, and they communicate. I think all of these headers shown in this price range are identical from one source, and there is a quality control issue. The only thing I think a vendor should do is make sure the product is ready to ship by looking at things like the holes etc. I sent a note to tuningpros to advise them of this issue.

Meanwhile the car runs fantastic, a dramtic improvement. But it also runs a bit hotter which I expected. It seems to me with the O2 sensors reading higher hydrocarbons ala no cats, the mixture will be more lean, and that will drive up the temperature. I have no science to back this up, just trying to figure out what the computer is doing.

What makes you think it's running hotter? Are you seeing higher water temperature?

Yes.

As a pilot I have long established the practice of scanning my guages about once a minute, and I know where they sit exactly, under a variety of operating conditions. My temperature guage is unquestionably sitting higher now. I have run the can around on five trips from full cool to full warm and it now consistently sits at a higher indicated temperature. Not dramatically, but with no room for question that it has changed.

I bought a set of ebay headers too...
from I believe it's "protunes" or "tunepros"
something like that...

it fits great...no fitment issue....
right now I'm running straight pipe
plus the headers which leaves me with no
cats...and I haven't got CEL except when my o2 sensor came off
but that was my fault...

How's the performance with your setup? Did you feel a big difference when adding the straight pipes.... and then when adding these headers?

[QUOTE= Meanwhile the car runs fantastic, a dramtic improvement. But it also runs a bit hotter which I expected. It seems to me with the O2 sensors reading higher hydrocarbons ala no cats, the mixture will be more lean, and that will drive up the temperature. I have no science to back this up, just trying to figure out what the computer is doing.[/QUOTE]

There should be no change in the mixture the DME is calling for (other than compensating for the improved exhaust flow), as it uses the first set of O2 sensors to adjust the mixture. The secondary O2s are there to monitor catalytic efficiency, not to adjust engine parameters. What did you do with your secondary O2s, anyway?

Patrick

Nice headers :)

Are you guys sure that they are from the same supplier as Maxspeed on ebay? I bought a set of these from them (maxspeed) for $574 over a year ago. If they are, then damn, you guys are getting a good deal! But either way I'm happy with the quality and performance and sound for the money I spent.

Here is the link to it http://cgi.ebay.com/ebaymotors/Porsche-Boxster-986-2-5L-2-7L-3-2L-Performance-HEADERS_W0QQcmdZViewItemQQ_trksidZp3286Q2em14Q2el1 318QQhashZitem220250203181QQitemZ220250203181

Surprisingly they are still priced the same considering others are selling for much less.

2nd set of O2s
 

My headers have four bungs, so all four are plugged in.

So you say the first set adjust the mixture - makes sense. And the second set tests for cat performance...then what? Seeing the cats not perform well does it adjust the mix or simply throw a code? I would thik it does not make any correction in the burn, leaving this to the first O2 sensors.

I have not thrown a code and obviously my cats are not performing. Many others have done this and also not thrown a code. Perhaps the failure mode for the cats does not include a burn like mine, but rather some other mode of failure the system is looking for?

My engine is running warmer - slightly. And while it may be this is due to a lean mixture I have another thought...where is the temperature sending unit located? I suspect it is near one of the headers and is getting local influence from the heat of the header pipe, giving it a reading different than the actual coolant temperature. I have a laser temperature guage and could read my coolant directly, but since I didn't do that beforehand I wouldn't have any comparison to go by. If indeed the temp sender is near the header I can do a quickndirty shield to test my idea.

this set up is great!!!
quicker respond on the throttle and way way way louder
before it takes off great after 4-5k rpm
now it will go at any rpm!!

Panameras,

Look at my picture of the headers in post #19 and compare it to the ones in the link you provided. Same headers, different name plate tack welded in four places. My says "HK Racing". And yes I paid $100, $50 for three day shipping from China!! The shipping label confirms it.

I still haven't received my modified passenger side yet. I think I might just find someone that will weld stainless and modify it myself.

I bought my on E-bay too
and the headers fitted perfect from both sides

Header Update
 

I just got an e-mail from the manufacturer telling me my headers are done. I looked at the pictures he sent and it appears it will clear my Tiptronic coolant lines. The test will come when I crawl under my car and install then. I will let everyone know the progress.

The modification was to the pipe on the end opposite the collector. I needed that pipe to turn out as soon as possible from the flange. The pics look good compared to the original headers.


http://986forum.com/forums/attachmen...tid=9496&stc=1

http://986forum.com/forums/attachmen...tid=9497&stc=1

http://986forum.com/forums/attachmen...tid=9498&stc=1