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removing the cat #19379 May 30, 1:02pm May 30, 1:02pm
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dondiemand OP
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removing the cat
im trying to search the forum about removing the cat but couldnt find one..anyway, has anyone tried this? did you notice any gain? im thinking about removing the resonator and the cat to squeeze out more juice..any opinions?

oops! my bad, this should be under the Custom Mods section, somebody kindly move it there..thanks a lot!

Re: removing the cat [Re: dondiemand] #19380 May 30, 1:15pm May 30, 1:15pm
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Removing the cat will give you around 7-10 hp. Atleast that is what ppl say here.



Re: removing the cat [Re: Spread Eagle] #19381 May 30, 1:19pm May 30, 1:19pm
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wow! eek really??!! the only down side is it's illegal here in so cal..that's why im kinda iffy about it

Re: removing the cat [Re: dondiemand] #19382 May 30, 1:30pm May 30, 1:30pm
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LOL. Illegal here to. But since when do cops do look under your car. grin



Re: removing the cat [Re: dondiemand] #19383 May 30, 1:34pm May 30, 1:34pm
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it sounds like shi*. it is pretty loud and you will get a check engine light because of the O2 sensors (2).

Re: removing the cat [Re: Steven] #19384 May 30, 1:37pm May 30, 1:37pm
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steven, have you tried this before? how about replacing it with a high flow cat? will it make any difference?..or maybe i should just take my resonator off, huh

Re: removing the cat [Re: dondiemand] #19385 May 30, 1:42pm May 30, 1:42pm
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cut the resonator off, weld pipe in place.

get high flow cat and weld it in place of the OEM cat.

with these 2 mods, you'll notice a considerable gain in performance.

Re: removing the cat [Re: Steven] #19386 May 30, 1:55pm May 30, 1:55pm
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great! i'll take your word for it! thanks steven cheers

Re: removing the cat [Re: dondiemand] #19387 May 30, 2:21pm May 30, 2:21pm
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don't get a ticket and get caught with a cat-less exhaust by the CHP, there is a heafty fine for that.

Re: removing the cat [Re: Steven] #19388 May 30, 2:22pm May 30, 2:22pm
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Quote:
cut the resonator off, weld pipe in place.

get high flow cat and weld it in place of the OEM cat.

with these 2 mods, you'll notice a considerable gain in performance.


Wouldn't a cheaper (and just as effective) alternative be to just hollow out the oem cat, after welding pipe in place of the resonator? That way you don't have to buy a high flow cat. Anyone have thoughts on this?


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Re: removing the cat [Re: Evan] #19389 May 30, 3:41pm May 30, 3:41pm
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if you remove the cat plus the resonator and overall is a straight pipe, you will here the POPping noise and its very annoying, very loud as well but the gain is noticable BUT you might get pulled over for that...

removing the CAT and replacing it with a resonator is what i did on mine and it sounds sweet plus the gain...

i will take pictures of it very very soon, so standby thumbsup

by the way, trust me on this one, i experimented on my exhaust a lot before rice


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Re: removing the cat [Re: Street Prototype] #19390 May 30, 3:59pm May 30, 3:59pm
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Quote:

removing the CAT and replacing it with a resonator is what i did on mine and it sounds sweet plus the gain...


Interesting.. do you have emissions testing where you live? and if so, how are you going to pass? deal


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Re: removing the cat [Re: Evan] #19391 May 30, 5:41pm May 30, 5:41pm
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if you remove the cat, won't the check engine light come on because of the 02 sensors?
i really hate seeing those check engine lights.
will the light still come on if you take out the resonator and replace the stock cat with a high flow cat? i was just looking at my exhaust pipes today and wanted to put a straight pipe in, but my friend told me about the 02 sensors and check engine light, that makes me not want to replace the cat... but i need more info about high flow cats


rip celi...
95 240sx
Re: removing the cat [Re: element_celica] #19392 May 30, 6:37pm May 30, 6:37pm
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you can replace the cat with straight pipe just put the o2 sensors in the pipe because they are a important part in how your engine runs and you need them

Re: removing the cat [Re: tomsgts] #19393 May 30, 9:15pm May 30, 9:15pm
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yes, i believe you can have the o2 sensors welded onto ur straight pipe(someone will correct me if i'm wrong cheers)... you can also get a universal high flow cat and have the sensors welded onto it grin thumbsup

here is random technology's web site, they have a universal high flow cat that will fit our celis
randomtechnology


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Re: removing the cat [Re: Bradcelica] #19394 May 31, 1:50am May 31, 1:50am
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no engine check light, no emission testing here, and the 02 sensor is not connected to the catalytic converter, check under your car and see if theres an o2 sensor connected to the cat converter, the o2 sensor is located before the catalytic converter commin down from the headers, if you can see yours connected on the cat converter, hmmmm thats weird but mine is not there...

like i said, ill post pics very soon...


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Re: removing the cat [Re: Street Prototype] #19395 May 31, 6:06pm May 31, 6:06pm
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cool..so if you put a straight pipe to replace the cat and the resonator, will there be that ricey pop sound coming from the exhaust? kuz i dont want that, and i want to take the cat out to free up the exhaust system.
hmmm whats a resonator for anyway? to quiet down the exhaust noise?


rip celi...
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Re: removing the cat [Re: element_celica] #19396 Jun 1, 12:49am Jun 1, 12:49am
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Quote:
cool..so if you put a straight pipe to replace the cat and the resonator, will there be that ricey pop sound coming from the exhaust? kuz i dont want that, and i want to take the cat out to free up the exhaust system.
hmmm whats a resonator for anyway? to quiet down the exhaust noise?


the resonator serves to quiet down the sound, but when you have straight pipe all the way, yes you will have the pop sound and its totally gay, i had a straight pipe before but now im using the resonator as a cat converter


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Re: removing the cat [Re: Street Prototype] #19397 Jun 1, 7:22am Jun 1, 7:22am
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Quote:
Quote:
cool..so if you put a straight pipe to replace the cat and the resonator, will there be that ricey pop sound coming from the exhaust? kuz i dont want that, and i want to take the cat out to free up the exhaust system.
hmmm whats a resonator for anyway? to quiet down the exhaust noise?


the resonator serves to quiet down the sound, but when you have straight pipe all the way, yes you will have the pop sound and its totally gay, i had a straight pipe before but now im using the resonator as a cat converter


so you took the cat converter out and replaced it with another resonator? and you left the stock resonator too?
i've heard of people hollowing out the cat convertor also... how's that done?


rip celi...
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Re: removing the cat [Re: element_celica] #19398 Jun 1, 3:19pm Jun 1, 3:19pm
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Quote:
Quote:
Quote:
cool..so if you put a straight pipe to replace the cat and the resonator, will there be that ricey pop sound coming from the exhaust? kuz i dont want that, and i want to take the cat out to free up the exhaust system.
hmmm whats a resonator for anyway? to quiet down the exhaust noise?


the resonator serves to quiet down the sound, but when you have straight pipe all the way, yes you will have the pop sound and its totally gay, i had a straight pipe before but now im using the resonator as a cat converter


so you took the cat converter out and replaced it with another resonator? and you left the stock resonator too?
i've heard of people hollowing out the cat convertor also... how's that done?


this will explain everything thumbsup

Linked Image


[Linked Image]
Re: removing the cat [Re: Street Prototype] #19399 Jun 1, 3:34pm Jun 1, 3:34pm
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JD - look at my edit of your photo... isn't that "sensor" the cat? Is your mid-pipe stock? On the mainland, we have an O2 sensor before the cat and one after the cat.

Linked Image

This is a picture of my mid-pipe... no resonator. O2 sensors not are on the other side of the piping...

Linked Image

Re: removing the cat [Re: Steven] #19400 Jun 1, 6:50pm Jun 1, 6:50pm
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what happend when you took out that sensor? did your check engine light come on? did you just take it off, or you cut the wires ?


rip celi...
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Re: removing the cat [Re: element_celica] #19401 Jun 1, 7:02pm Jun 1, 7:02pm
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i'm going custom; i have an obx racing muffler (with removable silencer). i'm about to have the resonator ripped out and have a 2 1/4" mid pipe put in. is the stock cat really that restrictive?? i'm not gonna yank the cat due to emissions, but if the stock cat is real restrictive then i'm gonna buy a universal random technology cat.


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Re: removing the cat [Re: Bradcelica] #19402 Jun 1, 9:25pm Jun 1, 9:25pm
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i wish i saw this thread a while back. i guess its been a while since ive checked the site. anyways. i did this mod. i removed the cat and the res and straight piped it to my TRD exhaust. it sounded horrible. hes right about the popping sound. i hated it so much, i paid another 60 bucks to have it put back but the shop damaged my o2 sensors in the process. my car sounds fine again but it runs crappy and i get the check engine light all the time. ive been in the process of getting them to replace it for MONTHS now. i threatened to sue them but hopefully i wont have to (its my friends dads shop). ive also been asking people to get me a set of used o2 sensors. theyre 150 bucks a pop at the dealer. i want some off a used gts. anywho, good luck.

Re: removing the cat [Re: dondiemand] #19403 Jun 1, 11:31pm Jun 1, 11:31pm
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i'm going to get a straight pipe made for me for track purposes only smile

Re: removing the cat [Re: Steven] #19404 Jun 2, 3:07am Jun 2, 3:07am
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Quote:
JD - look at my edit of your photo... isn't that "sensor" the cat? Is your mid-pipe stock? On the mainland, we have an O2 sensor before the cat and one after the cat.

Linked Image

This is a picture of my mid-pipe... no resonator. O2 sensors not are on the other side of the piping...

Linked Image


Sorry Steven but i have to correct you on this one, that is not the catalytic converter, look at the pic below...

Linked Image
Linked Image
Linked Image

Toyota Celica Catalytic Converter 1986-1989
Linked Image
Toyota Celica Catalytic Converter 1981-1983
Linked Image

the old celicas have the O2 seonsors on their cat converter, our cars O2 sensor is separate...

the illustration i have with the resonator replaced is the cat converter.

our cat converter is a bolt on type, the one your talkin about on my illustration you edited is not a bolt on type, thats why we have Universal High Flow Cat converter so we can replace it if we want too... cheers




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Re: removing the cat [Re: Street Prototype] #19405 Jun 2, 5:07am Jun 2, 5:07am
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Hey Street Prototype

Can you get a sound byte of what your exhaust sounds like now or do you know where I can find one? I want to straighten out my resonator pipe too, but i wanna hear what it sounds like B4 i do it. I would really appreciate it.

Re: removing the cat [Re: Miicha] #19406 Jun 2, 1:09pm Jun 2, 1:09pm
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sure buddy, heres the video clip of my exhaust thumbsup

Click Here


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Re: removing the cat [Re: Street Prototype] #19407 Jun 3, 6:37am Jun 3, 6:37am
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KOOL KOOL I WANT IT!!! I WANT IT!!! rofl goodjob goodjob grin

Re: removing the cat [Re: Miicha] #19408 Jun 3, 6:54am Jun 3, 6:54am
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thats a very nice exhaust! thumbsup

however, for you people thinking about the straight pipe system, i have a friend that tried it on his teggy, and got caught like the first week when he wasn't even racing. 4,000 dollar fine. could've put in a supercharger for that! spineyes


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Re: removing the cat [Re: Miicha] #19409 Jun 3, 7:03am Jun 3, 7:03am
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That sucks...but in DC i have heard louder... and they do not get pulled over..

Re: removing the cat [Re: dondiemand] #19410 Jun 3, 9:39am Jun 3, 9:39am
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yea CHP will not like you if you get caught cat-less

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