Eliminate Secondary Cats!!!!

[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.

[xclusivecar]

I'm not a Cat expert...but isn't it amazing that these companies that sell these bypass pipes will tell you that the secondary cats are there for no good reason...but Porsche had to put them there for some good reason...and they tell you that you will pass emissions...and then you don't pass emissions...

Man...it seems you cannot mess much with this car unless you want a BIG headache. Everything seems like it was meant to be there...except the SNORKEL!!! RIP IT OFF!!

[Brucelee]

If someone tells you that a cat has no use, they clearly should be lauged at.

[986Jim]

Didn't you keep your cat to slap back on for your etest? I have seen a lot of the WRX's and stuff pass with only the one cat on. How warm was your car? Many Porsche's will only pass when they are really warm and driven right onto the dyno without stiting to cool off before they will pass. The old 993 turbo was notorius for not passing unless it was basically driven hard right to the test and tested immediately. If the car cooled off for 20-30mins it would not pass...

A lot of different factors go into not passing. If your O2 sensors are not 100% they can slightly throw off the mixture. Too rich your CO is too high, too lean your NOX are off the chart. It's a balancing act. If everything is the way it should be you in theory should pass.

Either way, forget about it, put your cats back on for a bit then do your etest then pull them off again, it's pretty easy.

[Brucelee]

How about leaving the cats on and keeping the air just a bit cleaner.

That likely coudn't hurt.

[986silverbullet]

well thanks for all your replys to this Subject and its Obvious that there are alot of diffrent opinions

there hasnt really been a BOTTOM LINE ANSWER

soo i think im just going try it out for my self and see what happens ill let you no how it goes and ill also let you no if i Fail SMOG test

My current Mods are

EVOMS intake

MagnaFlow Exhaust

NEAR Future mods are

ECU UPGRADE!!!

So with the Intake Exhaust and bypass Pipes Im thinking and Hoping i will feel that Extra KicK!!!!