Hey guys, thinking about hollowing out my cat on my 94 lt1. Figuring I won't have many problems since most f-body guys I talk to say they do it. Just thought I'd run it by you guys first. wonders if you guys ever had any problems, bad mpg? running rich? Thanks guys!!

 

It will smell and be a bit raspy. But you'll gain a negligible amount of HP.

 

I did it to My 94 Z28, It made it sound meatier with My Flowmaster.

 

Just so you know you will loose power. Not gain it like said unless the cat is stopped up. There is tests all over on it. If you want to gain power. You have to have a pipe welded in the cat or get a test pipe installed.

I don't know all of the details but I believe it has to do with the exhaust bouncing around inside the open cat. Hurting the exhaust flow. A simple google will bring it up.

Edit: Here is one link for you. I know it is a import. But no matter what car or motor it is still going to be the same. http://www.importtuner.com/tech/impp...ion/index.html

 

Ahhh ic, do you think at the end they are saying to leave the cat on for street because techincally its illegal? or because i'll get a lot worst mpg? because right now its my DD until my little cav gets up and goin. I was planning on weldin just a pipe where the cat was. Sorry might sound like stupid questions, i'm just trying to get your guy's opinions. Thanks for the comments btw!

 

I welded a pipe in where my cat was after it nuked. I could powerbrake the tires loose at much lower rpm than I ever could before the cat was clogged even.

 

They are saying in the linked article that the best way to delete the cat is to use a straight pipe. Hollowing out the cat causes turbulence that may do more to harm the exhaust flow, possibly reducing power, not increasing it. Plus a "hollow" cat sounds terrible.

 

Cool yeah i wasn't planning on hollowin out the cat anyways, thanks for the comments!

 

If the cat is good leave it. If you do headers and ory get a high flow cat. Magnaflow makes a nice one. You don't want to run on the street without a cat. You will smell raw fuel, it will burn you eyes, and you won't pass emissions.

 

It sounds like ****, smells, and won't gain any power.

Rich

 

Personal experience...I've been running an off road Y pipe for years with no smell, no strange sounds, and no other problems to speak of. For dual cat cars you need to either get sims or have the rear O2's tuned out. Also, when installing the headers/Y pipe I discovered my cats had already been hollowed out by the previous owner and I had been driving it that way without even knowing it. Needless to say, the hollow factory cats made no sounds or smells to tip me off. It did explain why I had been getting intermittant SES codes for both rear O2 sensors though.....

 

Lol mine stinks i think it has something to do with the cam but wow it stinks my friends tell me it stinks like a snowmachine

 

You're probably running very rich with that big cam and a mail order tune.

 

You think a dyno tune would improve the stink?