My custom down pipes (turbo back cat delete with flanges)

[Audi S4 Turbo]

Here are pictures of my down pipes which I custom made to have the ability to remove and put back my secondary cats. We cut the primary cat open and deleted the existing cats. What we essentially did was cut between the flex pipe and the secondary cat with the 02 sensor hole.

We then added flanges separating the two on both down pipes enabling to take them off with 3 bolts.


Also, we custom made 2 3/4 pipes with an 02 hole with a flange on one side of the pipe to connect the flex pipe to the exhaust. (Not pictured) I'm sure it has been done, but has anyone else done this? Thoughts?

[01 S4]

looks good hope it seals for you

[Audi S4 Turbo]

That was just a rough draft in the pictures. The flanges were welded by an expert and the flanges have gaskets.

[b5s4blk]

pretty much the same idea just replace straight pipes with flanged cats

[exorcet]

looks good! i was thinking of cutting my cats out and welding in some 200 cell metallics... but i might flange it to run straight pipes / stock cats like that.

got my IC's in today.. when you gonna be ready to ROMP?

[Audi S4 Turbo]

looks good! i was thinking of cutting my cats out and welding in some 200 cell metallics... but i might flange it to run straight pipes / stock cats like that.

got my IC's in today.. when you gonna be ready to ROMP?

http://www.audizine.com/forum/showthread.php?t=214280