Cat Delete Pipe vs Cat Back Exhaust
 

Just curious what others think about these 2 choices, pros and cons. Everything I have read about the cat delete pipes has been very positive, the only negative is some minor fuel smell at times. For about 4-$500, (yes, there are more expensive ones, but why spend more for basically the same 2 pieces of pipe) you gain at least 25 HP and get the sound of an aftermarket exhaust. Really no negatives on cat back exhausts either, but at 2-3x the price is it worth it for a little more HP? My thought is that people go aftermarket exhaust mostly because of the better sound, which is also is accomplished with the cat delete pipes.

Also, how difficult would it be to install the cat delete pipes? Do you need to remove the bumper? Thanks.

If you do anything with the cats, do hi-flow cats. Cat delete will most likely through codes. Check out 2m fabrication.

I always caution this. Removing the Cats or otherwise messing with the emissions systems is a Federal Crime. If you live in a state where they do emissions testing or other inspections, you may well fail.

You will definitely fail emissions if you do cat delete.

You think if f high flow cats would provide a legal exhaust and provide a significant power gain GM would offer that as an option. I think they have an arrangement with BORLA that is very spendy (I think it must be GM installed) and I believe it offers a power gain. Maybe someone can correct me or add to this info. As far as the loud factor goes I admit I do look when I hear it but for me I got over that a long time ago. I will be checking out the turbo and supercharging systems that are being developed.

Is this true?? I added the Borla off-road x-pipe which is basically the same thing, passed emissions and it didn’t throw any codes. It has the O2 spacers. Why would this be different?

Roll The Dice
 

Void your warranty, fail emissions, ruin your resale, fry your engine. Do these seem like risks worth taking to gain 25 hp?

Have you smelled a modern car with cat deletes? You are absolutely going to fail smog if your state/city/county/whatever requires it to register the car.

You’re right it’s no different

Some states do a visual and the inspectors know what to look for. That is why you may fail.

Ditto to what others have said about the smell. Plus these hp gains are HIGHLY exaggerated.

Removing the cats will also increase black residue from unburnt gasses to form around your exhaust pipes and on the car. No big deal if you clean it often but honestly, high-flow cats are the way to go these days. Why risk added headaches in the future? Any horsepower gains or losses between using high-flow cats or straight pipes won’t matter and will largely be exaggerated and imagined. Just get high-flow cats.

A vote for a Catback like the aFe that keeps the Z51 valves :rock:

The GM Borla pipe costs about the same as the Borla S type plus aftermarket installation. Borla in general is spendy, but first rate materials and warranty. Any power gain is going to be minimal unless you can improve airflow in as well as out. The GM Borla is also only a bit louder than the factory NPP in track. The Borla S type is louder in Tour mode than the NPP in track.

I assume you're talking about the C7. Two differences: the C7 has 4 cats, and the x-pipe only removes the two smaller ones, leaving the main ones. The the C7 only monitors the main cats, so the OBDC system doesn't know the other two are gone. The C8 only has two cats, and they are monitored.

​​​​​​​Wrong. See above.

I was being sarcastic

Agree

One of the misconceptions of the decade - catless will produce big HP. On an N/A engine like this 5 hp if you're lucky. I have been working on a popular 4.0L bi turbo platform for the last couple of years. Catless pipes are the rage because misleading marketing has these guys thinking they're going to make big HP gains when in reality, even on the FI platform 8 hp, maybe, eliminating CATS.

CATS engineering has come a very long way since they were first introduced on ICE engines. Very much not worth the cost to eliminate them, then in some states (CA) they will catch it in an emissions inspection. With a new car you might have a couple of years, then be scrambling to get CATS put back in in CA and soon to be other states too.

According to the manufacturers of these pipes, you are wrong on all accounts, except maybe the emissions, but that varies by state. Any added HP is just a bonus, so that is very low on the list. I'm looking for a better sound like everyone else and don't want to spend 3-$5k on a cat back system. Performance to $ doesn't add up for me. Thanks everyone for the replies.

And manufacturers NEVER exaggerate the benefits and minimize or ignore the negatives, right?

I can guarantee you that if you have an engine problem, GM will look at those cat delete pipes and say "oh, so sad, too bad." Probably if you have any drivetrain issue. "Oh, your mods exceeded the designed HP, any issues are because of that." Might want to watch the video below.


And it is a clear violation of federal law to remove the cats. Maybe in some states you'll get away with it, but any state that requires an inspection is going to catch it as soon as they fire up the car and smell the exhaust, then fail you.

The manufacturers say everything is hunky dory. If it's on the internet, it must be true, right? LOL.

You mean just like the “sky is falling” and “don’t do that” response you just gave? Sound like a Karen! Lol!

”The manufacturers say everything is hunky dory. If it's on the internet, it must be true, right? LOL.”

Does this go for GM also when they tell you everything is fine with the trans and the wheel cracking issue with the C7 GS and Z06 wheels?? They said it was a non issue.🙄