I bought flowmaster american thunder 3" Cat-Back. I am wondering if I should remove my cat and put a straight pipe in its place. Will it sound louder or better? Ive heard that the 80 series isnt that loud.

 

You don't say where you're from, or if emissions is a concern for you. I'll assume it isn't, or you wouldn't be asking the question (if it is, leave the cat in place).

The cat does modify the sound a little. A good high-flow design cat will not be a signficant restriction, however.

I've set off car alarms driving through the parking lot. I'll let you decide if that qualifies for "that loud".

 

Ive set off alams with my subs before,,,I dont care!



To: nixhex311
get rid of that cat. if your laws says you can, I did I love the sound and its not that loud!!!!!!

 

No muffler company or exhaust company is going to bend one up and put it on for you if you are in the US. They might bend it up, but they can't leagally install it (depending on state) and a police officer could site you for faulty emissions equipment, but it is a nice sound increace as well as a drop in back pressure compared to the stock converter.

 

why not just gut the cat and call it good?

 

I was thinking about doing this to my car also. I looked at it the other day and i have some sort of pipe running into the cat. what is this? What do i do with it when there is no more cat?

thanks

 

Just leave the cat alone. It's there for a good reason. If you're worried about good flow, just buy a free flowing aftermarket job.

 

as for the tube, it's part of your emissions also. O2.

 

The tube is from the AIR pump, to help the catalyst in the converter do it's job. And I think you should just leave the cat alone too, unless you replace it with a high flow cat that also is plumbed for the air tube.

 

some will say a gutted cat doesnt sound to good..

 

i have pipes in the place of mine and with the stock manifolds it was LOUD once i got the headers it became quiter but sounds very mean. i say go for it, if you have a way to get inspected.

 

http://goingfaster.com/spo/290hp305.html

 

MAC macs a pipe for single cat 3rd gen camaros. it bolts right up, and it has that pipe thingy coming out the side, it is 75 so probly about 85-90 after shipping.

http://www.macperformance.com/macsto...o/cmrohdr.html[/URL]
its the last item.

 

federal law says you cant. and some shops will install a pipe there for you and some wont... the cat kills a lot of sound, but a good high flow one wont kill a lot of power. i would defineatly get rid of it.

and to this day i think that my setup is best. i pass visual inspection every time and i have all the pleasures of straight 3" piping.

gutted cats sound no where near as good (plus they dont flow as good) as straight pipe...

 

i also heard that gutting the cat is as bad as having a stock one... because of the shape of the cat.. the air circulates instead of flows straight through thus creating a bad air pocket and causeing backfires and bad gas milage and such

 

thats what happens, but i dont think its as bad as stock one....

 

no it is worse, u get less power but better sound, why go threw al that work, just put a piece of 3" pipe in their, more power and better sound

 

That is sooooo true.... a buddy of mine replaced the cat with the 3" pipe and says he wont go back.... i have to agree with him it sounds beautiful.

 

unless the car's just for the track, get the high flow cat. it's not only just as effective to put the high flow cat in, it's not nearly as irresponsible to put a pipe in. do you know why there are emissions laws? it's because of things like this. have you ever driven in LA? giving up like 1hp is such a minor thing...

 

i had open pipes for awhile and i must say that after i got a high flow cat and flowmaster the car drove better. i gavve up some pwer but more drivability

 

i gutted mine for a seat of yoru pants improvement


although as you can tell i do agree straight pipe is way better (cuz thats what i got)

 

Leave the cat alone.

I'm not telling you that you can't mess with it, but don't make a big deal of doing it on this site.

I know it's not a big deal, but it is illegal, and this site doesn't need us to be "suggesting" the idea. What you do off this site....well, that's up to you.


{edit} just to clarify, I'm not saying don't do it, I'm just saying that this site needs to be careful about what things are being suggested....from a legal standpoint. It's a lot bigger deal than a lot of you think it is.

 

c'mon now
there are SO many threads, you do realize that one post in one thread is almost as non helpful as my post

 

yeah, I sure do, but it was brought to my attention in a different conversation, so I just figured I'd pass it on.

I think I tripped and landed on the TGO soapbox or something....

I've been dealing with all kinds of legal crap over t shirts and such....

 

i replaced mine with a high flow cat. i felt at least it's legal. and really, does anyone have a before and after dyno sheet of with a high flow cat and a straight pipe. i'm sure it's not much it at all. the main reason i think people do it is due to the $$$$.

 

i agree with brodyscamaro......i gutted mine and it made my car a HECK OF A LOT louder!! and also dropped my et for a 15.9 to a 14.7..........so i DO suggest doing it........but i was also told that this change isnt normal for most cars.....

 

Well, as was said before it is against FEDERAL law to remove or modify a catalytic converter, violating this law can carry stiff penalties (Fines, jail time) if they decide to persue it. And remember if you are even driving through a state that has emmisions insoections, the police there can inspect your vehicle and issue tickets for removed emissions equipment. Being in their state makes you subject to their laws, and ignorance of the law is not an accepted excuse in court.
Now i doubt that they would be so **** as to inspect your vehicle...but if you were pulled over for a traffic violation, and hte officer felt like it he could do it.

Just get a high flow cat and enjoy the released power and the knowledge that you are in compliance with the law too. The cost of a high flow is peanuts compared to the fine you could recieve for not having a cat at all.
Just my 2 bits.

 

A good new cat only saps about 5 horsepower from the numerous magazine articles I've read. Like everthing else in the tech threads there is always a few that claim they went a second faster and picked up gobs of horsepower. There cat was probably bad or something. If your car is just a toy you can legally gain an exemtion from emission (like I did) and it's not that much of a hassle. Ask for details at you test facility--for the record I only can testify that in Ill. it wasn't a hassle. It also depends on your motor. Stock or ever slightly modified motors need a little back pressure.

 

i know i got-cha