Removed 2nd cat today!!!>>>

[mazdamp3_18]

as some of you may know i had my resonator removed a cuple weeks ago and i had 2 inch piping replacing that..... i decided to go out on a limb and get the 2nd cat cut off.... and have 2.25 in piping replacing all of that.....

i have to say that there is a HUGE sound difference with the larger piping and i can tell a little bit more power.... theres a big difference with throttle responce....

Maybe if i drive it hard enough i can get flames to shoot out the tail pipe.... LOL .... J/K

its got this really tough loud sound to it.. but its not too loud....

just thought i would let you guys know...

ill get a sound clip soon..

 

[frady2001]

alright, do you just have the second off or both. how bad doese this effect emissions. did you have to adjust any engine stuff, did check engine light come on. thanks.

 

[mazdamp3_18]

i just removed my 2nd cat not the pre cat... and i have to resonator... no CEL's yet and i dont plan on any and i didnt have to adjust anything... i can tell a nice gain with the 2.25 piping...

also i cant tell anything different with emissions b/c my tip isnt any more dirty than it was so there seems to me not anymore sulfer content....

 

[MP3skaterNC]

hmmm... i might have to stop by a muffler shop and get the the exhaust mod quoted, i was thinking about going with 2 1/2 all the way, but i wonder what 3'' would do.....

 

[mazdamp3_18]

theres gonna be a pretty loud raspy sound if you go 3 inch

i would reccomend 2 - 2.5 inch piping if your keeping the stock muffler...and not going the turbo route

 

[J Goodz]

i'm an idiot

I know this is prob a stupid question because i've been a member on this forum for a long time now. But what exactly is a cat. and what does it do? how would you remove one? whats the diffrence between the first and 2nd?

-joe

 

[LzrBluMP3_427]

Is it possible to pass emissions with all the mods you did mazdamp3_18? And J Goodz a cat aka Catalytic converter helps reduce emissions and in the process it restricts airflow therefore taking away some horsepower.

 

[mazdamp3_18]

i have no clue if ill pass emissions... i have heard of cars with no cats at all and passing emissions.... but im not sure if i would pass with just the pre cat.... i have a feeling i would but Michigan dosent do testing so i dont really have to worry about it.... i know all you cali guys do... which sucks

 

[Syzygy]

In AZ, they do "the mirror check" when the emissions are checked. They have a mirror attached to a handle that they use to view the cat assembly. Since you still have a cat, they may not notice, but if they see the mods (the piping), questions may arise. Just a note of concern.

 

[LzrBluMP3_427]

mazdamp3_18... can you post pics of what the mods looks like? I am very curious about possibly doing this.

 

[cfbjr]

In California(The strictest in the USA as far as emissions go) removing the cat will fail you right away. They do a visual as well as sniffer test. The smog testers have extensive information on every car as to what equipment it is supposed to be equipped with, including how many cats and what type of cats. You are allowed to modify anything after the second cat (removing the resonator would be ok), but the cats have to be the unmodified OEM cat. Of course, a lot of this depends on who's doing the inspection and how thorough they are. But most won't risk having their license pulled and the ozone nazi's watch them pretty close.

To answer the question a cat is short for Catalytic Converter. It's purpose is to chemically treat "harmful" exhaust gasses(hydrocarbons, carbon monoxide and oxides of nitrogen) by turning them into harmless byproducts, carbon dioxide and water.
You don't remove them if you want to pass a smog inspection.
There's probably no difference between the two as far as their function, it's more their shape and configuration. They do restrict the airflow because the exhaust gas has to pass through a fairly dense element inside them and if they get messed up somehow(running too rich can do this) they can create too much backpressure in the exhaust and cause engine performance problems.

 

[mazdamp3_18]

just give me a few days and ill get some pics....