[SeanArc]

whats up guys, i have a question (s)

i have a 2.0T arc stage 2 (PPC, opti-flow intake, and a custom cat-back exhaust system)... i want to get a downpipe and thats where my question lies.... i kno id have to download the stage 3 software from bsr if i did get the downpipe because the software for 3 is different than from 1 or 2... will this software work with not the bsr downpipe? i want to get a custom one with asports cat because it will be cheaper tha the $900 bsr one. is there any reason why id be limited to the bsr one? is there somethin special about the cat or the pipe that would cause my car to not like the custom one? let me kno guys

 

[oslowley]

I don't see why not. So long as the physical measurements are the same.

 

[mbodo]

you'd have to make sure the EGT and O2 sensers are in the right spots to work w/ the Stage 3 software. They get moved around A LOT.

 

[SeanArc]

where are the egt and 02 sensors supposed to be?

 

[mbodo]

where are the egt and 02 sensors supposed to be?

That's an easy question to answer: Go look at your car

.. you have one O2 sensor before your stock cat, and your Lambda sensor (sorry, my mistake from earlier post) and 2nd O2 sensor after the stock cat.

On the BSR downpipe, the lambda sensor is the only one located after the hi-flow cat. This cable is used to extend the reach of the stock cable.

Why the second O2 sensor is located before the cat is beyond me. I was under the impression the car was measuring the difference between the two sensors in order to determine the car's emissions. The Stage 3 software must have a "work-around" for this.

 

[SeanArc]

awesome, so as long as i make sure the 02 and egt sensors are in the same place, then the stage 3 software should work fine with a custom downpipe?

 

[ctrlz]

A couple of things:

A lambda sensor is Bosch's name for an oxygen sensor (a.k.a. O2 sensor). It is so-named because the stoichiometric A/F ratio of 14.7:1 is called a "lambda" of 1.

The three sensors involved are the pre- and post-converter oxygen sensors and an exhaust gas temperature sensor (EGT).

The purpose of having two oxygen sensors is to make sure the catalytic converter is doing the best job possible. Here's a decent explanatory page. The idea is to make you replace the converter if it goes bad, and to prevent you from removing it. The 9-3 probably goes into limp mode if it thinks the converter is shot.

The EGT usually goes on the downpipe, ahead of the converter. If exhaust gases are too hot, the substrate will melt off the converter grids, potentially clogging the converter, and certainly reducing its efficacy.

If pipes are not pre-drilled, I would make sure these sensors are mounted EXACTLY where BSR recommends. T8 is not very forgiving, and BSR is only altering the parameters used by T8.

 

[mbodo]

A lambda sensor is Bosch's name for an oxygen sensor (a.k.a. O2 sensor). It is so-named because the stoichiometric A/F ratio of 14.7:1 is called a "lambda" of 1.

This makes a lot more sense.

So essentially the EGT is the only thing that is moved before the cat.

awesome, so as long as i make sure the 02 and egt sensors are in the same place, then the stage 3 software should work fine with a custom downpipe?

Possibly. FYI, the cat that is used in BSR's 3" downpipe is stamped "MADE IN USA", so you shouldn't have too much trouble finding the right one to install. I have some pre-installation pictures, I'll see if I can find a part number.

 

[SeanArc]

ya thatd be awesome, itd be so much cheaper to get a custom one instead of the bsr one

im also thinkin of doin just a 2.5" downpipe instead of the 3" onethat leads into a 2.5" cat-back...2.5 all the way im thinkin

u think that by askin bsr i could find out where the sensors are placed exactly and maybe even like a blueprint?

 

[ctrlz]

u think that by askin bsr i could find out where the sensors are placed exactly and maybe even like a blueprint?

Maybe you could find pictures of the pipe.

The alternative is to just copy the locations on the stock pipe.

My understanding is you want the EGT as far upstream as possible. Saab must take into account cooling as gases pass through the turbo. Other manufacturers mount EGT ahead of the turbo.

 

[mbodo]

ya thatd be awesome, itd be so much cheaper to get a custom one instead of the bsr one

im also thinkin of doin just a 2.5" downpipe instead of the 3" onethat leads into a 2.5" cat-back...2.5 all the way im thinkin

u think that by askin bsr i could find out where the sensors are placed exactly and maybe even like a blueprint?

I think the minute you deviate from the specs BSR has engineered for their software, you're in custom-software territory.

I highly doubt BSR would release blueprints or mechanical diagrams for their product, except perhaps to a patent office.

Here is one of the pics I found of the downpipe pre-installation.

 

[ctrlz]

Here is one of the pics I found of the downpipe pre-installation.

So, I would guess the top, hex-shaped bung is the EGT and the round one is the oxygen sensor. The EGT is on top, so that's easy to service. The O2 sensor is probably positioned mid-pipe in such a way that it can be serviced easily from under the car.

 

[mbodo]

The O2 sensor is probably positioned mid-pipe in such a way that it can be serviced easily from under the car.

Easily if your daytime job is working as a contortionist Cirque du Soleil.

 

[ctrlz]

Easily if your daytime job is working as a contortionist Cirque du Soleil.

Point taken. I really haven't been under there looking. But I figure they gotta put these bungs somewhere that you can replace the sensor without dismantling the whole car!

 

[mbodo]

The sensor on the top is really easy to get to; it's right on top and you can get a wrench around it no problem.


Removal of the EGT and 2nd O2 sensor appears to require the removal of what SAAB calls the "front pipe", or the pipe connecting the silencer to the downpipe:

"9. Detach the front pipe from the catalytic converter.
10. Remove the heat sheild over the steering gear.
11. Remove the heat shield over teh catalytic converter.
12. Remove the temperature sensor.
13. Remove the lower oxygen sensor."
from WIS - Catalytic converter - To remove
Ergo, a nice gentleman at the local muffler shop had had the privilege of doing this for me.

 

[SeanArc]

would it be possible to run a custom 2.5" downpipe with the stage 1 software? or would that not be good/ cause the car to not run right?

 

[mbodo]

would it be possible to run a custom 2.5" downpipe with the stage 1 software? or would that not be good/ cause the car to not run right?

I think you're still in custom software territory ...

For what its worth, I've had to run my Stage 3 hardware on my car WITHOUT the software for several months while BSR is "investigating" alternatives due to the lack of 93 Octane fuel in California (... and several other states ...)

The car appears to be running just fine.

 

[ctrlz]

The sensor on the top is really easy to get to; it's right on top and you can get a wrench around it no problem.

So the sensor on top is the pre-cat O2 sensor? I thought it looked like an O2 sensor.

My reading said the EGT is usually just downstream of the turbo (i.e. ahead of O2 sensor #1). But really there is no reason one has to be in front of the other. The EGT will just give a cooler reading the further back you go. As long as the ECM accounts for this, all is fine.

What a pain that you have to take down those pipes to service these things!

 

[mbodo]

So the sensor on top is the pre-cat O2 sensor? I thought it looked like an O2 sensor.

Yup, O2 sensor right on top. Both the EGT and the 2nd O2 are after the cat, which is why I was confused with the new setup of the BSR system, which moves the placement of the EGT sensor in front of the cat, but physically in about the same place.

I don't imagine you would notice too much of a heat drop through the cat, but I'm sure it is enough for that nasty little Swede (better known as T8) to notice.

 

[Crosby]

downpipe?

Does anybody know where you can buy a downpipe for these cars? I have a 2004 9-3 2.0t and have been looking everywhere. Does anybody know any good websites for performance parts in general for these newer models? I bought the k&n cold air intake and on other threads they said how it would prob set off the check engine light, sure enough it did. They said bc you need to figure out a way to get the same amount of air coming in, to go out. Im looking to do downpipe and cat back but cant seem to find a downpipe. Any suggestions?