Has anyone ever hollowed out cats while they are inline. Just put a new exhaust system on and it doesn't want to come off again. Somehow I feel the need to gut that cat. I don't really want to go through this again. Please don't ask why I didn't just hollow them out while the exhaust was off. And please do tell me there is a way to make it right without cutting the new system off.
Thanks

 

All you do is cut the cat out, for and aft of the cat, pull it out, hollow it out, and weld it back in.


Primary rig is Green Thunder:
95' F-150 XLT 4x4, 302, 5 spd, MSD 6A, Flowmaster American Thunder Exhaust, Sunroof, Clear corners w/ Diamond headlights, CD player with 2 10" subs and some 32" BFG Muds .

That's it for mods now, saving for a Stang. Check out my Gallery for a look-see.

 

Sounds easy enough if you own an exhaust shop. Unfortunately I do not. Wasn't too bad cutting the exhaust between the cats with the dremel but the way its in there, there is no easy way to get all the way around the pipe other than where I cut it, which is why I cut it there instead of cutting 1st cat off all together. The joint where the Y pipe meets the cat is so rusted that 1st effort to cut it off there doesn't even make a leak, 2 out of 3 bolts cut off and tried cutting through the middle. No way to get to the 3rd bolt unless you take the exhaust manifold off and I don't have the down time to do that. Cannot pull the Y pipe off at the manifold because drivers side is exhaust welded on and bolts are shot. (By exhaust welded I mean like 1/4 inch of "corosion" all the way around) Besides if I were to pull the manifold off I would want to replace whole thing and am not in a financial position to do that at the moment. So my thought is to drill holes poke something up there and shop vac it out, then seal up the holes and wrap the whole thing in Thermotec or equivolent. Can anyone tell me if this might work before I go through all this trouble?? Thanks for the input though I appreciate it and if I had the set up that is probrably what I would do.
Thanks

 

Well, take a hack saw and cut the cat out, I don't know what vehicle your asking questions about. You can go to autozone or the like, and get small pieces of pipe that allow you to put two pipes together with clamps. I'm doing this when I take my cat out. I'm going to have an exhaust shop weld them, or have my dad weld the seams up. So if you can't weld, get two of those pipe connectors and have a shop weld them in.


Primary rig is Green Thunder:
95' F-150 XLT 4x4, 302, 5 spd, MSD 6A, Flowmaster American Thunder Exhaust, Sunroof, Clear corners w/ Diamond headlights, CD player with 2 10" subs and some 32" BFG Muds .

That's it for mods now, saving for a Stang. Check out my Gallery for a look-see.

 

Hey thanks for your input MustangGT221, My husbands exhaust fell of so I made him leave it off. Just got done hollowing out the cat. Not as hard as you might think. Took just about an hour. Am going to take it for a run in the morning and then probrobly tomorrow night put the exhaust back on and seal it up. My exhaust never go anywhere, thats why they call me Mamafix. Appreciate your input greatly.

 

probobly the best thing to do is just weld in a straight pipe, and then weld in the catylitic converter casing over the pipe to (hopefully) fool the emmisions inspector. My understanding is that hollowed out cats perform and sound poorly compared to a straight pipe.

 

Thanks, the cat however is not comming off short of cut and weld and I do not have the welding technology. Also I wouldn't mind just getting rid of it except the flange and pipe at the front of the cat is 3-4 in diam with an oval hole, comes off the Y pipe that way. You don't by any chance know of online service who sells funky stuff like that do you?? Haven't found any myself. Appreciate the help. You have no idea how much.
Thanks