Autralian Boxster Exhaust Ssytem

[NickCats]

Aussie,

Here ya go :

A catalytic converter (colloquially, "cat" or "catcon") is a device used to reduce the toxicity of emissions from an internal combustion engine. First widely introduced on series-production automobiles in the US market for the 1975 model year to comply with tightening EPA regulations on auto exhaust, catalytic converters are still most commonly used in motor vehicle exhaust systems. Catalytic converters are also used on generator sets, forklifts, mining equipment, trucks, buses, trains, and other engine-equipped machines. A catalytic converter provides an environment for a chemical reaction wherein toxic combustion by-products are converted to less-toxic substances.

http://en.wikipedia.org/wiki/Catalytic_Converter

Nick

[aussieboxy]

Thanks Nic

[Tool Pants]

You do not have the pre-cat on the exhaust manifold that is required in North America.

[Cloudsurfer]

This raises an interesting question. Would it be benficial for us North American guys to "upgrade" to the non pre-catted headers, and then either run the high flot secondary cats that are sold, or simply use the factory secondary cats, with a Lamda sensor before and after?

Patrick

[Tool Pants]

This is a 2003 S owned by Paul in Australia. You can see there is no pre-cat on the exhaust manifold. He just has the rear cat. The 2.5 also did not have a pre-cat. The 4 cat system started in 2000.

Paul and I exchanged hp numbers and the difference was like 1 hp. But if you wanted to elminate the pre-cat I suppose you could buy ROW manifolds. You would need to check ROW and US part numbers to make sure it would work.

[Tool Pants]

For others, this is the pre-cat, which is part of the manifold. Aussieboxy does not have this.

[aussieboxy]

Yeh those 2 pics exactly depict what I was talking about. I'm surprised there is only 1hp difference considering the different flow charateristics though.

Thanks for the update.