Ok someone give me the rundown on test pipes... I know they replace the cat , but someone explain o2 simulators , what they do , how they work , why I need one , and if there's different types and what those mean , i.e. mechanical and electrical. Thanks in advance

 

A testpipe is simply a straight metal tube. This tube replaces your catalytic converter. I'm sure you know what the cat does but in case you don't, it "cleans up" the exhaust gases of the byproducts of incomplete combustion - even a fuel efficient one such as ours, doesn't have a complete combustion process and lots of unburnt hydrocarbons escape out into the exhaust pipe.
The O2 sensor installed in the cat detects, you guessed it, O2. The more O2 in the exhaust, the less got used up in the combustion, the more unburnt hydrocarbons there were, OR, the more unburnt hydrocarbons that didn't get "cleaned up" by the cat. When you put on a testpipe, nothing gets cleaned up, so the O2 sensor thinks the cat isn't doing its job anymore and needs to be replaced. That's when you get a CEL.
To avoid a CEL, you must either fool the ECU into thinking that the cat is still there and working properly. You can do this by installing an electronic O2 simulator or removing the sensor from the mainstream of exhaust flow like in a mechanical device like the non-foulers. The electronic one simply interceeds in the signal between the sensor and the ECU by putting an artificial signal that keeps the ECU happy. The actual signal never gets there. The non-fouler pulls the sensor further away from the exhaust stream and also reduces the orifice size to prevent too much exhaust gases from getting to the sensor.

 

what headers work on what test pipe?? does the collector size of the header and the inlet size of the test pipe need to be the same??

 

Any header with work with any testpipe, I plan on using a Megan header with my Megan testpipe. The collector is 2.5" and the testpipe is 2.36"

 

shouldn't these 2 sizes match up?? do you have to get an adapter to make these 2 pipes work together?

 

Think about it for a minute. If a test is designed for this car and is a direct bolt on, that means that the front and back end will match the existing stuff perfectly. Therefore, if this is the case, then if you get a header that is designed for this car, it will also have the matching end on it. The same goes for any cat back exhaust system built for this car. All ends on every piece will be OEM mate-able.
Conclusion: You can mix and match header, testpipe, cat-back exhaust to your heart's desire.

 

Is a testpipe and O2 simulator worth the trouble? Anyone have real world performance gains?

I'm wondering if this mod is worth the trouble considering the impact it will have to the environment.....unless everyone is truly only using it on the track.

 

The o2 simulator is not a mod people do for power. It is an electrical device that simulates what the ECU (OBD2) expects to see from a normal working catalytic converter.

 

They advertise the test pipes(most companies) for about +/- 3 h.p.gains.
Some people saw more,like = 9-12 h.p.gains,on dynos.(depending on other mods.)
In my case,(WITH A MEGAN T.P.) ,the engine revs more freely,and I would say,maybe 2-3 h.p.gain.(With intake,header,and catback;no brand names MENTIONNED )

 

Testpipes do make a noticable gain plus are fairly straight forward to install.