I was thinking about removing my cat for sound n performance, does anyone have anything to say about that performance or sound wise or would i be better off just cutting off the muffler and running pipe in to a tip?

 

Have fun trying to pass emissions!

Without a cat and a muffler, it'll be louder than ****

 

Hey hackabuse i didnt know **** was loud!

 

DON"T TAKE IT OFF!!! It will sound like ****! I just did and it's way loud and very raspy. Total rice.

 

Just get a high flow cat, pretty much the same thing. I wouldn't even think about it here in California. You get cought with no cat, your car is impounded and the shop that did it get's fined $3,000.

 

then shouild i just try and hack the rear muffler leading to stright pipe

 

You're not going to gain anything, it's not worth it, too far from the engine, Its going to sound like ****. no muffler would sound horrible, put a magna flow on it. just put a high flow cat or leave it alone!!!

 

+1

 

i want to know that too, would there be gains if you knock out the baffels in the muffler and how much louder are we talking.

 

I'm not exactly sure so don't quote me on this, it's just my opinion...

You still need some back flow, so getting rid of the baffles may cause increased air flow, but may not be good for you're engine, especially if you want a straight pipe with no or a high flow cat, you need some resistance. A muffler is basically there to create a little back pressure and determine the exhaust note to make it sound nice. Getting rid of baffles would make it very loud, but not in a good way, probably create a vibrating noise, and turn it into the biggest fart can ever, probably going to sound very very bad. The muffler needs the baffels to move the air around too and keep it flowing, you don't want to cause turbulance within the muffler, especially with the stock one being that big. Magna flow makes a straight through but has baffles just to direst the airflow straight out. The best you can do it get a high flow system, they are Dyno tested for the most HP gain.

 

hmm so should i just put in a muffler..

 

expencive route and get a cat back system

 

On a boosted car you do not need back pressure. Back pressure is the last thing you want. I would go without a cat (of course you have to worry about immision's if your state has them). Always ways to get around that. For performance (more so if you have upgrades), no cat should give some nice gains. We had a high flow cat on my turbo car, and was blowing turbo to manifold gaskets, once we took it out no more. I do realize there is a diference between turbo and supercharger,

 

Go with a Highflow cat and a catback

 

NAME STEALER.....


Anyway, don't you will throw a CEL, not pass emissions, and It is WAY loud. and raspy.

 

There are CEL fixes, in Cali you only have to pass emissions on a new car after 5 years, then every 3 after that. But im not sure what the law is where you live but here you get reamed for taking off cats.

 

I took the cat off on my car, you get the smellies which is you can smell like 2 or 3 cars back, the power difference between a hi-flow cat and no cat are not worth it, your talking about max 5 hp. I put on a hi-flow cat.

 

rofl @ "the smellies" you don't have a cat so there's nothing burning the hydrocarbons...and yea...it stinks...alot, I hate getting behind people with no cats, makes me very thankful the recirc function of the Cobalt's HVAC system works so well.

In regards to the earlier post about backpressure and turbo's/superchargers. EVERY car needs some backpressure. Whether the car is tubro'd, NA or blown the engine needs something to push against, not to mention exhaust scavenging. If you truly believe cars don't need any back pressure, replace your exhaust with some bigass buspipe and see how your car performs then, too much backpressure is certainly a bad thing, but not enough will effect you just as much...some cars respond to exhaust changes much worse then others (anyone who's messed with headers on a 5.0 fox mustang will know what I'm talking about)...from stock a bit less backpressure won't harm anything...but you're not going to see any gains changing the exhaust on an unmoded Cobalt either.

 

is that true, in Pa even if your car is emissions exempt, it will not pass inspection with a CEL on

 

and that's how we do it, WORD!!!

 

What nobody has said so far is the fact that the car probably won't even run right let alone have more power. Is there not an O2 sensor plugged into the cat?. New car engines are designed from the ground up to run with a cat, this is not a '78 vega that had one thrown on after the fact and is being choked down by it.

 

I've seen people go to great lengths to "fool" the second O2 sensor into thinking there is a cat there..it's not plugged into the cat, it's in a spot after the cat, to measure the exhaust and make sure the cat is working properly.