Performance Exhaust and Header for Boxster

[efahl]

Originally Posted by mn box s

it will help? even with no cats?

Probably not, and the absence of cats shouldn't cause drivability problems. The pre-cat sensors are used by the ECU for mixture control, they sense whether the mix is lean or rich and under certain operating conditions adjust accordingly to keep the cats at their optimal operating temperature. The post-cat sensors are OBD sensors, and verify that the cats (and pre-cat sensors) are working properly. I'm not familiar with how late model DME operates, but I've never heard of code that changes mixture based upon post-cat sensor input.