Phew! What a job that was! It's a pain in the butt to do without a lift, but brute strength & ignorance prevailed!
I was able to get the car up on my ramps and jackstands high enough to get under it with a little "wiggle room". Then I loosed all the nuts & bolts, put two floor jacks under the pipes and slowly lowered it down. Then I used a drill to break up the screen inside the pups, got all those chunks out and then fashioned a tool out of a piece of metal to reach in and scrape all the junk out. It took probably 45 minutes for each cat to scrape it all out. I wanted to make sure all the stuff was out, so I went over and over and over it with my scraping tool and they were very clean when I finished. After that I put the whole assembly back on the two floor jacks, raised it up enough to get the bolts back into the middle bracket and then proceeded to get the pipes back into the exhaust manifold flange and tightened it all back up! The total job took about 3 hours.

For anyone attempting this, give yourself plenty of time because the material inside the pups is dense and sticks to the side of the pipes. It took alot of scraping to get it all clean. I may have gone a bit overboard, but I didn't want any of that junk to remain inside and risk clogging the main cats.

:flag

 

I can certainly understand your reasons for gutting the cats, and I can apprecuiate the labor you put in..really... but you could have just cut them out all together.I'm sure you would have passed inspection without them.I pulled all 4 cats and have NEVER had a problem with emissions...Just my .02:D

Pics of my TPIS header-No cat-x-pipe-Corsa Install on my home page...:D

 

Great news Lou....I cut mine out completely.I replaced it with a smooth pipe.Much better sound than before.

 

I thought about cutting them out completely, but here in NY there can be some jerks when it comes to emissions testing. With the cats gutted it still appears stock and as long as the car's warmed up for an emissions test it'll still pass! There's a whole lot of crap inside those little bastichs!!!!! :eek:

 

What is it that you are actually scaping out? What type of material :cheers: :)

 

I'm not sure how to describe it - as you look into the cats there's a screen-like material. I started gutting it by drilling into the screen with a large drill bit, being careful to NOT hit the pipe walls. When I got a few holes in it and tipped it down a whole bunch of gray powdery looking stuff came out. The screen material was made of some kind of fibrous material that broke up into chunks and fell out. After all that was out there was a layer of what looked like glued paper on the walls of the cats. I know it's NOT paper, but I'm trying to be descriptive! I had to scrape all that out with my created scraper! I know this is not a very technical answer, but in all honesty I don't what the heck the material is!!!

 

Very Sneeky :cheers: :D

 

In my 300ZXTT we did that but be careful of the dust created. That is bad stuff to breathe. It was recommened to squirt oil into the cat and wear a mask.

 

I am curious, after gutting the cats do you get a strong smell from the exhaust like unburned fuel? Many have had this problem and ended up getting hi flow cats.

 

Just courious.....did you notice any difference in power or sound?
Thanks

 

I did not notice any power difference....they say pups are worth 5 hp but I definetely noticed a change in sound.Louder and throatier.

 

Keep in mind he did not gut the main cats; just the pre cats (that are useless once the car fully warms up).

C5LOU; I plan on doing this, but worry about the loosened "dust" flowing down the pipes and possibly cloging the main cats. How were you able to control the direction the loosened material flowed?

 

Mike, what I did is this: When I laid the pipes on my bench I kept the bend of the pipe facing down. Just doing that will make most of it go out onto the floor. Then every time I'd get more junk loosened up I'd pick the pipe up and shake it down, always keeping the pups facing the floor. After I was completely done with all the scraping I took my Dirt Devil with a narrow nosel attached and vacuumed out pipes. During the whole process I made sure that I never let the pipes get tipped so that the pups were higher than the rest of the assembly.

Now the unfortunate part: It's 15 degrees and snowing, so I won't get a chance to try this out for sound/power gains (if any) for awhile! I'm also waiting for my new exhaust to arrive. So, when Old Man Winter finally gives me a break I'll put it all back together and try her out!!!!

 

Thanks for the indepth info. I too am waiting on the arrival of my 2002 Z06 titanium mufflers. When I go to install them, I might as well remove the H pipe and gut those pesky pre-cats. :)

 

Actually, the pre-cats are filled with asbestos and other enviornmental pollutants that GM wanted to dispose of in a sneaky way. Glad you exposed them. Nick :)

 

What most impressed (depressed!) me was the density of the crap in those pups! It's hard to believe anything can "flow" through the stuff! It's like a charcoal type consistency mesh that runs the full length of the pups. When I drilled/hammered into it the stuff turned to powder much like a piece of charcoal would. I did not have a mask to wear, but as soon as I discovered the amount of fine dust it was generating I opened up the garage door and some windows. I'm sure I breathed more of it in than I should have, but hopefully I'll live long enough to outlast this damn snow and drive the car again!!!!! :D