Whate are the implications of cat bypass pipes?

I don't care about emissions. (we have no such enforcement in MI)

I have Fabspeeds, but an otherwise stock motor.

Bypass pipes can be made by a local shop with O2 sensors in place.

No info is available through searching the archives...

Thanks everyone!

 

Please?

Come on!

Just kidding.

I have the attention of a fabricator that does great work. So I'm trying to figure out if it's worth the effort.

 

P1CR,

As I mentioned in another thread, Wilber on this board has a downpipe for the 996 that is a straight bolt on, and you can fit the O2 sensors on it with no problem.

He just did a C4S last weekend and a friend installed one on his Boxster S.

 

MI doesn't have emissions checks? Does MI have annual inspections? My area doesn't measure emissions, but does have a visual inspection to insure that a catalytic converter (cc) is at least in place. Although many cc bypasses have a place to insert the 02 sensor, they still don't look much like the regular cc, so you may need to replace the cc to pass annual inspection.

 

MI has no inspection of any sort.

Sad isn't it?

So...any thoughts on the HP/torque changes?

 

Also, I believe there are two O2 sensors. One before, and after the cats.

Will that screw everthing up?

 

from what i read cel will light when something is removed. they (sensors) know a temp difference when something, ie. cat is missing.
however a spacer can be built to move the o2 sensor back and hold heat. oro you can buy 'em for like $200

 

whats with all these cat bypass thread from like 50 years ago..... they had emission back then?

 

bypass pipes with 02 sensors don't pass inspection and make no sense anyways........ try low restriction high flow, however you will lose torque, gain hp. Mine on the black aero, were 200 cell, nice, loud, light, but torque was sacrificed. My aero had headers to highflow cats to open exhaust, very raspy, very loud, but cool!! The car also had ducted air intake and ecu mods. Great car!