Both cars plus on an 01 S (friends)

from the great amount of knowledge that i have amassed from the internet, this is what i think i know:

porsche boxster (other than early 2.5l) has two sets of cats - pre-cats located on the headers, and secondary cats located on the mid pipes.

boxster has two sets of 02 sensors: one set on the headers before any cats to determine efficacy of fuel/air mix, and a second set after the pre- ats on the headers to ensure that the cats are working.

if you put headers on that do not have cats you have four options:

1) live with the cel you get from the second set of 02 sensors telling the computer that the cats are not working.

2) extend the second set of 02 sensors (two wires each) to a location after the secondary cats on the mid pipes. this way the computer will still know you have cats in the exhaust system.

3) fool the o2 sensors. a quick seach will provide several options. if in the us of a you can buy 'foolers' (maxspeed motorsport sell a set, as should most entry-level autoparts stores). these are devices that distance the o2 sensors from the direct exhaust flow. the sensors see less exhaust as a result and think that the cats are there and working. can't find 'foolers'? go to an autoparts store and get a couple of sets of 'spark plug savers' ($6/set) - devices designed to distance the spark plug from the combustion chamber to prevent fouling - same thread pattern as the o2 sensors and bungs; drill them out and use them to distance the o2 sensors from the exhaust flow.

4) get a row flash. all piwis devises come with the ability to flash either row or us. you can buy one yourself ($4k) or find a local mechanic who has one and get it done. benefits are (a) start car without depressing the clutch, (b) computer no longer monitors secondary air pump operation, and (c) computer no longer monitors cat effectiveness (ie, no cel with catless headers).

no rockets, no science. we are smarter than the computers in our cars.

I am astonished by the fact that this type of exhaust configuration produced positive results for you . Best of luck.

JD

Do these headers work on a '98 2.5 with Tiptronic?

NOT SURE - I read on another forum somewhere that it's different - clearance issue, you will need to research

hi, I had a 2.7 that I installed a set of header ( B&B)and had lot of problems with cells. I put the same exhaust on a 01 S , 3.2 with a 2.5 cat and extened sensor wires. I also rased fuel pressure .3 bar, the car runs great, +12hp at wheels. PS much better sound and added porsche sport mufler.

Very interesting!


I safety wire the second set of 02's under the car so they can read "fresh air". Never throws a light. The secondary 02's do not effect the tune of the car and are only looking for cat efficiency (as stated above)

I have done this 20-30 times on the 2.5 race cars running the 5.2 ecu and the 7.2 cars (2.7/3.2)

The later 7.8_40 (997/987) does not like this. Porsche actually dumps a ton of full into the system to see if the secondary 02's exist in the system and throw the CEL if they do need read the predetermined amount of fuel. Porsche does this during normal freeway steady state cruisng :(


B

Actually I believe the 7.8 DME was first installed in the 03-04 986 and yes it will throw the cel light (ask me how I know) but some of the header have 2 ports so you can install both o2 and they work fine that way.

Is there such thing as headers that fit a 2.5 TIPTRONIC? My particular car is a '98.

The rest of world program is easily loaded by a PST-2 if you have the DME learning code (must be obtained from a dealer).

RoW flash is no big deal at all if you find someone with a PST2 or PIWIS (I have a PST2) and you get your DME and Immobilizer codes from the dealer.

Any other way you try to make this work on a 2000 or newer car is going to be a mickey mouse fix. You can try O2 simulators, try moving the secondary O2's behind the secondary (well now the only) cats (if you leave them, that is) cats, or just get used to seeing the little yellow lamp lit up (and never knowing if something else is wrong also).

Anyone know if CA smog check accepts ROW flash since it hooks up to OBDII port ?
:chicken:

Hello, I'm new here and I've recently installed a set of Ebay headers on my '00 Boxster S. After just a couple of kilometers (I'm from holland and we use the metric system :p) the CEL went on...

So I got some CELfix pipes that I placed between the rear O2 sensors and the header. These take the sensor out of the exhaust flow and the CEL stayed off

BUT with the CELfix things there's a new problem; when I drive the car and take it above 5500 RPM there's a huge cloud of smoke (I'm pretty sure it's fuel) out of the exhaust. When I let the rev's down the smoke is gone again. I can drive the car at WOT up to 5000 RPM with no problem, but when i get to the highet RPM's the smoke returns...

The weird thing is that the CEL doesn't light up, not even when the smoke starts..

It looks like the thing mentioned above (about the fuel dump to check the catalytic converters) but that's only on 2003 and up cars, and mine is 2000

Does anyone know if the headers are to blame for the smoke??

The engine is all stock and in mint condition and has only 72.000km on it (about 45.000 miles), recently replaced the AOS but that was more a preventive measure.

Seems unlikely. What color is the smoke?

The smoke is light grey and smells like gasoline..

I'm not trying to be a wiseguy, but I'm pretty sure it's gas...

The engine doesn't have any oil in the coolant, coolant level stays the same, no sludge in the oil system. Even the oil filler cap is perfectly clean on the inside. There's no abnormal vacuum on the filler cap or dipstick....

Tomorrow I'll put the stock manifolds (with the catalytic converters) back on and take the car for a drive to see what happens...

The thing is, even if all of the O2 sensors in you system were not working or hooked up, the engine would go to a default factory setting, which is a bit richer than optimal, but not enough to cause smoke.

I've been working on it all day, and I'm pretty sure my NEW AOS is broken...

I didn't check it right away because I thought that it could not be te source of the problem since it was a new part and only about 500 miles old...

The hose to the intake manifold and the pipe on the AOS had zo much oil in it that it started to drip once the hose was disconnected...

Now my question: was I so unlucky to get a broken new part, or did it break because of something else?

Is it possible you overfilled at the last oil change? My first inclination was toward a bad AOS...

Well, I'm pretty precise on those things, so I would say no :p

I already ordered a new AOS @ pelicanparts (somehow it's much cheaper for me to order parts in the US, even with Germany being our neighbour country, and some parts are up to 50% cheaper in the US)

In the pelicanparts forum was something very interesting; There's a PCV valve in the driver side valvecover and one of the two vacuum hoses to the AOS comes from that PCV valve. If this valve gets clogged with oil residu or something, the vacuum on the AOS will rise and result in AOS failure..

There seem to be people that replaced the AOS four or five times in just a few hundred miles before looking any further...

Problem solved!!

I saw someone else on this forum who posted a movie with the very same problem as my car had!

Maybe this is helpfull for him to:

The problem was the oil filler hose... When this gets older the plastic gets hard... My guess is that, when I replaced the AOS, the tube broke when I removed it from the oil filler tube on the engine..

There's a ribbed part in the hpse where it bends... there was a crack in between the ribs.. When the engine was at idle, the tear was closed and the vacuum under the oil filler cap was good, but when the car accellerates the engine somewhat tilts over and opened up the crack. With this, the vacuum dropped and the AOS stopped working, resulting in huge clouds of smoke.

I'm happy I found the problem and the repair only costed 30 euros!

:)