I have a "3 ZZP catted DP and decided I want to go cat less on the stock exhaust. Any suggestions on how to hollow out the cat on the ZZP piece without hacking up the entire downpipe? Thanks

 

I used a 2.75" piece of aluminum pipe from O'Reilly and just twisted and turned it it into the cat and it cored out the cat. It was very nice because the core came out with the pipe

 

Sorry the original post wasn't really very clear I want to hollow out the cat on the ZZP downpipe without having to cut it up.

 

Yes. So you have a 3" downpipe. Take the downpipe off. Take a 2.75" pipe and core out the cats by pushing it through the cat material. Idk how else to say it. The hole you core out will be 2.75"

 

Good luck hollowing out a spun metal cat. It can be done but is not fun.

If its a ceramic cat its easy.

Also, the hollowed out section will create eddies in the exhaust stream. It's better to keep the cat or install a true catless pipe.

 

Not sure about inspection and emissions in TX but I'd buy a true cat less pipe and just have a cat shroud welded where the cat should be. Would pass a visual but you'd be found out if you have a sniffer test.

 

Lol have fun with a spun cat. I've removed a few of them now, and it's a miserable process. When I've done them it's been hours of time with a hammer, chisel/screwdriver and a torch, and that was on a small motorcycle cat. I'd hate to imagine the amount of time on a 3" cat. What happens with the metal ones is that you end up breaking it in small chuncks. Eventually you flatten it to a solid blob, and you have to just beat at it until you break it up enough to get it out in small sections.

Why do you want to hollow it out anyway?

 

Damn, I think it is a spun metal version. Luckily there's no emissions testing in my area just visual

 

I have a stock pipe already hollowed out I'll sell for 50 plus shipping

 

Thanks but I'll stick with the ZZP 3 inch because I also have a 2.9 pulley waiting to go on