Mitchcpc

Supercharged
Joined
Jul 1, 2007
Messages
260
Cat Box Opened Up

OK, you guys wanted to know what is on the inside of our cat boxes. Time to find out.

I had a few moments this morning and I thought what the hell, let's just see. So I took the cat box off my '07 figuring this would be easy and after I took the guts out I'd just stick it back together and take a ride.

So you start with the kitty on the bench. First thing is take the heat shield off. The construction is such that you can't just cut the thing in half, because innards are on a frame that is spot welded around the box. You have to decide which half you want to take off and then grind down the spot welds after you cut the shell in half. I used cutting disks on my grinder. Took about an hour and a half to get it apart.

From what I see, there really is no "Baffling" to speak of. The exhaust goes into the chamber through the magic metal tube and then just goes out to the three exhaust ports. I think I will remove the magic metal tube and stick it back together. OOPS, I can't stick it back together, I think it is stainless and I can't weld stainless, I don't have a MIG welder. Guess I should have thought of that first? Who is going to volunteer to stick it back to gether for me if I pay postage both ways. Surely this educational post is worth that!

This modified CAT box will only be used for off road competition. I have a new one on order for street use.
 
Last edited:

RADEMIS

Supercharged
Joined
Apr 25, 2006
Messages
201
Location
PLYMOUTH, INDIANA
Welder.

you don't have to have a mig welder to weld stainless steel. You can use a stick welder with stainless steel welding rod. You just need to keep the amperage down as low as possible until you get the holes filled back up.
That is very interesting to see the inside of that thing. I wonder if you could have broke the stuff out of the inside just from the inlet hole? Rademis
 

Mitchcpc

Supercharged
Joined
Jul 1, 2007
Messages
260
I'll try that.

Thanks, I'll try that. I have a buzz box and a flux core wire welder, I think I'll try the wire welder.

I don't think you could break the innards out through the holes. No straight shot anywere. It sure is amazing that the exhaust from all three cylinders goes into that one tube of "magic metals" .
 

Jimmysdeals

.020 Over
Joined
May 19, 2008
Messages
15
Location
Central, Mississippi
Great Pictures Mitch.. I believe you can buy a 1# spool of stainless wire for that welder of yours and burn it back together.. If not let me know I might be able to help you out. Your pictures really help. I want to try and cut one the other way (vertically it will be easier to weld back together) and remove everything except for the big pipe coming in and the 3 smaller pipes going out.. I'm thinking nightrocket is going to help me out on a box to gut..


JIMMY :)
 

Sidecar Flip

Living Legend
Joined
Jul 16, 2006
Messages
6,359
Location
20150 Mc Carty Rd. Deerfield, Michigan 49238
It's all about breaking up the soundwaves of noise. That's how your cage muffler looks inside too. You can get stainless rod for a scratch start (stick) welder but you'll have an oxidation problem and most likely she won't fuse. Same goes for a flux core machine. You really need to use a shielded gas torch and thorated tungsten electrodes with Argon as the shielding gas. Nice honeycomb Palladium Substrate. Looks like a hornets nest without the hornets.

If you absolutely get in a bind, send it to me and I'll weld it back together and put the heat shield back on.
 

Mitchcpc

Supercharged
Joined
Jul 1, 2007
Messages
260
Speaking of...

Hi Flip. I knew you'd say that. Thanks. I'll let you know.

Speaking of "Palladium Substrate", have you seen what you can sell a cat box for on e-bay? Crazy prices. I am going to put the "Magic Metal" tube out of this cat box on there once I get it out.

Whoever want to make this a sticky go ahead. I couldn't figure it out. And if anyone wants additional pics from another angle or anything let ke know that as well, I would be happy to send them to you.
 

Baggage1

Turbocharged
Joined
May 26, 2006
Messages
997
Location
NW Fl
Ride
2006 Rocket III
So the only difference for an N cat is the magic metal tube is empty? Huh, no wonder the thing weighs a ton empty or full. If you need practice I have 2 full ones in my shed collecting bugs.:rolleyes:
 
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