Squidbelly wants to know the best way to gut a manifold cat
 

The last Toyota sports car (MR-S) was literally resurrected when someone discovered that reaming out the manifold cat prevented a lot of problems.

Ours seem to be holding up. But we know that a header works in tandem with a tune to eliminate the torque dip. But of this is restriction, the other is over heating the cat with timing adjustments. Really our stock manifold is quality piece except for the cat.

I was pondering giving this a shot but what tools would I need to gut the thing for off-road use?

Google

Some dude did this already on the forum and loved his results.

@NickFRS

Google I only find straight pipe cats, ours is an oval hard loks hard to ream.

I have never tried it, but if I did, my first thought is to sharpen a pipe and use it like a hole punch.

Look through Nick's posts that he has started. Maybe pm him about how it was done.

Thanks, just plain Nick ?

@NickFRS
http://www.ft86club.com/forums/showthread.php?t=55770

Care to document/explain how you came to these observations?

I used to burn them out with a stick welder when I needed too. big heavy welding rod and turn up the juice...
fairly easy and fairly quick just be careful.

This is what I did on prior cars

Shive has one of his posts (I think the one on stg2) where he shows how the cat limits timing in both vvt and ignition. Its pretty much common sense, unburnt fuel in the combustion chamber burns and heats the catalyst.