Im debating on gutting the cats on my GSL-SE....what are the pros and cons?
I dont want it sounding like *** and I sure dont want it backfiring more, but If the HP gain is good then Im for it.

 

pros, more power, better louder sound, u can remove yer airpump and AVC
cons you wont pass emissions, thats really the only con

 

first thing it WILL backfire more secone it will be way louder and have little to no performance gains. Think about it. all that crushed honey comb in there don't you think gutting the cat will cause turbulance. Putting it simply i have seen many dyno tests for this and in most cases the car loses power because the gutted cat causes alot of turbulance increasing backpressure alot. so the only gain is a louder, slower car. Itmight feel faster, but thats only in your head cause now you'll hear it more!.

 

If you want to do a topnotch job of it, and make it perform good, I would say why not gut it, then backweld a chunk of exhaust pipe into the cat body?

That way you would still have the cat underneat for a visual inspection (if thats all you have to pass) and not have to face the turbulance issues from an open cat.

 

^^^^ word.... that's what i was about ot post!

 

Or just take them out and install a straight pipe...

If you want real performace gains remove the entire OE exhaust sytem and install a Racing Beat Road/Race exhaust system, or at least the Racing Beat Header and have a custom exhaust fabed from the header back.

The performance gain will be much more noticable then just gutting the cats our...

 

Racing beat headers are on the way. Possibly a full exhaust in the next month...but for right now I might just run a straight pipe in its place. har har...I dont have to pass any emmsions here in AL.

Thanks for the help guys.

 

I guess I'll throw my 7 cents worth in here since I did that with my old cat....

Yes, you WILL gain noticible power (along with cutting/removing the belt on your air pump if you haven't done that already). Depending on how you do it, assuming you did like I did and you gut it completely, you'll have a thin-walled metal "shell" that you will hear some, but it wasn't as bad as the crappy sounding FlowMaster muffler on my car that I can't wait to get rid of...

Here's something I did wonder though... with this new cat I have now, I'm thinking that eventually, I might drill some holes straight through the brick for better air flow. That way, there will be SOME performance gain and still keep the exhaust somewhat quiet and maybe prevent it from backfiring as much.... because yes, it will backfire....though not as much as when I had my exhaust setup as headers with the flowmaster bolted directly onto the collector and NO PIPE! The thing was RIGHT under the passenger seat (and it was L_O_U_D)

 

just wait till you get the exhaust, straight pipe on the stock muffler and/or gutted cats sounds like ****.

 

Gutting the cats doesn't give as much performance as having a good replacement pipe because of the turbulance created by the shape of the cats and the "imperfections" left when you gut it. And it's FORKIN' loud without them.

Otherwise, pros are a bit more power, you dont' have to worry about them clogging, you can remove the ACV... but they're small pros really. I'm leaving mine on and just plumbed my Air pump directly into the cats, bypassing the ACV so I could remove it. I figure I'll leave it that way until I have the money to get an RB system.

Jon