gutted my cat today

[Black 02 SI]

well i did it, lol. i was debating on doin it for a few weeks, got bored ripped it off and its hollow now, lol. i put on the 02 sim and no light yet only driven about 5 miles. car pulls harder, but sounds like balls :( its my boost controller, lol. i dont want to floor it cause i hate the way it sounds, keeps the boost down nicely. i think it made a differene havent goten on it real hard yet, and i need to reset my ecu in the morning. now i need bigger injectors, throttle body, smaller pully and some tuning. :)

[TrippZ]

would it sound better wiht a test pipe?

[Peking]

would it sound better wiht a test pipe?

Yeah, sorry but gutting the cat is pretty ghey. Complete waste, do you know how much a OEM cat costs? You would have been much better of with getting a test pipe. Hell you could have just got a custom one.

Only silly ricers would gut their cats because they actually believe that is well worth the trouble and don't even know that they could have got themselves a test pipe or race header.

Dammit mang, why didn't you talk about this before doing it?

[Black 02 SI]

i dont give two shits about getting a stock cat. i had reasons to do it this way. i wanted to keep it looking stock but perform like a test pipe. now if a cop or whoever looks under the car they will see a "stock" cat, and not question it. i HAVE gotten stopped at random check points around here and one of the things they check is the exhaust. if they look under and see no cat or a shiney "test pipe" they will question it and look further into it. also why do you say it's pointless???? how many people have said they felt a nice difference with the test pipe(which is the sam thing i have now) and its pretty damn close to a race header if you ask me maybe a few less horse. no need to jump down someones throat for doing somthing. it's not a ricer thing to do, how many of your friends with stangs or camaros do this???? bottom line it was FREE and with the charger i feel a HUGE difference. oh yeah and i have a stock cat that is being given to me, so i cared even less about having to worry about getting a new cat.

[RMC22]

reow.

:D

[SF-SI-02]

I know you don't care, but it doesn't sound like it was a waste. :D

[Silvershadow]

The other prob w/gutting out the Cat is the material in the Cat is very BAD for your lungs.While u were gutting the Cat out u were probably breathing the DEADLY Dust.I hope u don't develop lung probs.

[Gearhead Geek]

...how many people have said they felt a nice difference with the test pipe(which is the sam thing i have now) and its pretty damn close to a race header if you ask me maybe a few less horse. ...

acctually, it's not the same. basicly you just created a "swimming pool" for your exhaust gases, vs. a tunnel. while you've prolly gained a tiny bit of hp/tq, it's not as much as a testpipe, and definately not close to a race header. normally the exhaust flows smoothly through a testpipe or rh, but in a gutted cat, it hits the big chamber you've just created, and gets disrupted like crazy (hence the extremely raspy sound you get from the gases bouncing all around). this also causes massive ammounts of backpressure. while a LITTLE bit of backpressure is good (in NA cars), a lot is bad, and you now have a lot. and if you're boosted, that's probably one of the worst things you could have done. now i know it can be argued that a cat creates a lot of backpressure, which it does, however the cat keeps the exhaust gasses moving straight while they pass through it (as you probably saw the cat is somewhat like a honeycomb inside). but now, as i said before, they hit that large chamber, and bounce all over the place.
now, i won't go into the "you're a ricer" rant as many would do. instead i'll offer you a suggestion: get a friend who's good at welding (or if you are, do this yourself), and cut the "cat" section out. then take a piece of pipe and weld it inside of your now hollow cat, so that the exhaust has a straight path to follow. you may have to drill a hole through it so that the o2 sensor that goes inside will have enough clearance, or you may not, you'd have to figure that out when you do it (either way it doesn't matter, because the second o2 sensor is just checking for cat efficiency, and with the o2 sim it gives a constant reading of ~1.25V regardless).
oh, and the test pipes for our cars don't look like B series test pipes, they acctually look like cat's. many mechanics can't even tell for sure wether it's a testpipe or a highflow cat.
and one last thing, you just destroyed a piece of your car that costs $1041.06, and that you could've sold to a junk yard for a few hundred ;)

[Black 02 SI]

actually i have gutted cats before so i knew to wear a mask. also as i said before i dont care about how much it costs or anything. i have a magnaflow high flow cat sitting at home, u think that would be better than what i did, but not as good as a test pipe? basically i was bored and did this for the hell of it to see if it made any difference. now i am either gonna weld my high flo on or just order a test pipe. what do you think would be better? test pipe i would think, right?

[audomatik]

i say more power to ya. i've seen many power gains from gutting many of cats. GTIs, GSRs, Sis, etc and I've noticed tons of gains. Not once have I seen a downside (except maybe the sound) to gutting a cat. I don't know why everyone is ragging on a guy for gutting HIS cat. Who cares how much money a stock cat costs. People ruin parts of their car all the time. How about all the people that drill their amps to the back of their seats? How much do rear seats cost? Probably alot. I dunno to each their own. I wont gut my cat because I dont have a hookup with emissions testing in my state... yet, so I dont see myself getting a highlfo cat or test pipe.

[LHD_EP3]

Bad move!

[Black 02 SI]

how is more power a bad move?

[aRz]

Yeah, sorry but gutting the cat is pretty ghey. Complete waste, do you know how much a OEM cat costs? You would have been much better of with getting a test pipe. Hell you could have just got a custom one.

Only silly ricers would gut their cats because they actually believe that is well worth the trouble and don't even know that they could have got themselves a test pipe or race header.

Dammit mang, why didn't you talk about this before doing it?

First off do you mean you replaced the cat with a straight pipe or hollo'ed out the inside of the cat.

If you Hollo'ed out the inside of the cat i agree w/ GearHead Geek

If you Cut the cat then...

I "cut" (meaning replaced it w/ a straight pipe.) my cat once i got my custom 2.25 mb piping done. the car was extremely loud w/ the apex-i N1 muffler. ( the only bad thing) so i sold the muffler and put the stock axle-back on.

all i have on my car is aem sri, hp shortys and 2.25' piping.
I dynoed at 153 whp and 132 tq.
i run 15.2's at morrosso in the hot ass weather.all the time w/ dyno sheets and time slips to prove it.

I can honestly say i felt the most power gain out of cutting the cat.
More than my intake,header,or piping.

Just to let you know im def. not a "silly ricer" here are my pics if you want to check out my ride for any rice...

http://www.ephatch.com/forum/showthread.php?t=39831

[toda_power]

not ricey at all.

[Silvershadow]

I hope it wasn't one of those $2 paint mask that doesn't completely wrap around your nose. :yellm:

[aRz]

Now.. after saying that if you Hollo' ed out the cat then i tottaly agree with



acctually, it's not the same. basicly you just created a "swimming pool" for your exhaust gases, vs. a tunnel. while you've prolly gained a tiny bit of hp/tq, it's not as much as a testpipe, and definately not close to a race header. normally the exhaust flows smoothly through a testpipe or rh, but in a gutted cat, it hits the big chamber you've just created, and gets disrupted like crazy (hence the extremely raspy sound you get from the gases bouncing all around). this also causes massive ammounts of backpressure. while a LITTLE bit of backpressure is good (in NA cars), a lot is bad, and you now have a lot. and if you're boosted, that's probably one of the worst things you could have done. now i know it can be argued that a cat creates a lot of backpressure, which it does, however the cat keeps the exhaust gasses moving straight while they pass through it (as you probably saw the cat is somewhat like a honeycomb inside). but now, as i said before, they hit that large chamber, and bounce all over the place.
now, i won't go into the "you're a ricer" rant as many would do. instead i'll offer you a suggestion: get a friend who's good at welding (or if you are, do this yourself), and cut the "cat" section out. then take a piece of pipe and weld it inside of your now hollow cat, so that the exhaust has a straight path to follow. you may have to drill a hole through it so that the o2 sensor that goes inside will have enough clearance, or you may not, you'd have to figure that out when you do it (either way it doesn't matter, because the second o2 sensor is just checking for cat efficiency, and with the o2 sim it gives a constant reading of ~1.25V regardless).
oh, and the test pipes for our cars don't look like B series test pipes, they acctually look like cat's. many mechanics can't even tell for sure wether it's a testpipe or a highflow cat.
and one last thing, you just destroyed a piece of your car that costs $1041.06, and that you could've sold to a junk yard for a few hundred ;)

[aRz]

I hope it wasn't one of those $2 paint mask that doesn't completely wrap around your nose. :yellm:

ohh boy! :shockm:

[Black 02 SI]

so this magnaflow cat i have would be better than stock but not quite as good as a straight pipe, correct? the whole thing is i dont want to have a straight pipe, and i dont want to have a stock cat. i am gonna go weld this high flo on here, and see how this works. hopefully i will not need the 02 sim with the high flo, what do you guys think?

[aRz]

Basically the magnaflow is less restrictive as the stock cat. But it will not make the car that much louder than stock.

having a straight pipe is the best wather it be a race header or regular piping.
Usually a race header is going to give you most power since the runners on the header are that much longer and ends w/ a large collector.

[STP03BlueSI]

I hope it wasn't one of those $2 paint mask that doesn't completely wrap around your nose. :yellm:


LMAO...why those are the best you can get 5 at the dollar store for a buck. :winkm: