Eliminate Secondary Cats!!!!

[986Jim]

The 00-04 has two cats. One right off the manifold and one farther down the pipe.


http://www.pwr-tech.com/parts_exhaust.html They claim 8hp increase. It's technically against the law to remove a properly working cat converter from your car for any reason, so they say for off road use only. It has been said that you will pass emissions testing however you may not pass visual if you have one.

This is the bypass pipe he is refering to, I don't think those are resonators. The pre-cat is right off the manifold like this:


Thanks to 986online our great sponsor for that pic...

He wants to pull off the secondary cat with the pipe in the first picture.

[nastyboxster]

I did the Borla muffler and then the 2nd Cat bypass. It was pretty loud with the Borla muffler and even louder with then 2nd cat bypass. Definitely added punch especially at higher rpm's. I just dynoed the car and yelled 247.6rwhp with a few other mods (no chip yet) . You can check out my dyno here http://986forum.com/forums/performance-technical-chat/6040-dyno-results-mods-post45989.html#post45989

Have to do emissions test in the next few weeks to renew my insurance. I'm crossing my fingers.

I think eliminating the 2nd cats is a good way to get better sound and add some hp at the same time without spending a lot of $. Takes under 1 hour to install too.

[Brucelee]

I would bet my lunch money that here in CA, dropping the cat would make a Box fail smog. And as you may know, that is a capital offense here in LA LA land.

[nastyboxster]

Failed my emissions test, so I have to put the cats back and retest. Luckily, it's once every 2 years and it's an easy swap. Be prepare to do this if you are going to install the bypass pipes, but I think it's worth it for a bit more punch and a louder sound.

[Brucelee]

Originally Posted by nastyboxster

Failed my emissions test, so I have to put the cats back and retest. Luckily, it's once every 2 years and it's an easy swap. Be prepare to do this if you are going to install the bypass pipes, but I think it's worth it for a bit more punch and a louder sound.

The emissions police and greenies are out to get you!!!!!!!!!

[Tool Pants]

Originally Posted by nastyboxster

Failed my emissions test, so I have to put the cats back and retest. Luckily, it's once every 2 years and it's an easy swap. Be prepare to do this if you are going to install the bypass pipes, but I think it's worth it for a bit more punch and a louder sound.

Did you fail the visual inspection? In California they first inspect your car to make sure all the emission equipment is in place. If it is not in place then you do not even do the actual smog test because you have already failed the visual test.

[xclusivecar]

As Tool Pants said...did you fail the visual or the actual emissions test?

[nastyboxster]

The actual emissions test. They weren't able to detect the bypass with the visual. I only failed by a very small margin with regards to Nitrogen. Someone told me to put in ethenol mix gas and try again before putting back the cats. It suppose to burn cleaner.