Contour Enthusiasts Group Archives Forums Modifications Duratec Performance Gutting Pre-cats/Mystery Mod?

Ive been really wanting to do this and i'm wondering if its worth it? What kind of dyno proven gains are out there? Also does anyone in SE Mich. do this, and how much$$?? Or is this something simple enough to take upon by myself?
And yes I already did the search.

1998.5 Silver SVT
Brullen cat back
kkm
off road Y
painted grills
mirror tint

I have been wondering about this as well- I may be thinking of the wrong cat but when I asked my muffler shop friend he told me that there wouldn't be any noticeable gains from this...just more sound.

Not the cat comming off the why pipe, there are two cats on the exaust manifolds before the y-pipe and supposably you get noticable gains when performing this mystery mod.

YUP warm and dry

This might not be an issue with you guys but, what about the emissions? Are the 2 small cats there for the cold start emissions, or are they critical for getting the car to pass inspection? I am going to buy a set of headers. One more thing. A gutted cat may flow very poorly. The hollow cat acts as an expansion chamber causing back pressure. From what I have seen on the dyno in different applications a gutted cat isn't really worth any power because of this, just alot more noise. A straight pipe on the otherhand made a big difference. I know that a straight pipe really isn't much of an option here. I think headers would be a better idea. Hope I could help.

Roger

Headers don't have pre-cats and therefore higher emissions (if you need to worry about that). The mystery mod is like the poor man's headers.