Question about Removing Cats

[Jet Black]

Ok I dont want to gut my cats because I still want to be able to pass smog check next year. So I was wondering is their anything wrong with just removing the whole exhaust after the exhaust manifold.

[pinoyesv6]

first thing im thinking of is the sound. if you remove the the exhuast well, you're getting rid of the majority of the restriction and well, the sound might just be too loud for your taste or hell, even the law. that might be someting to think of.

SES lights. you might get a few of those since you are removing some of the cats.

cost. i know a dp can cost a few hundred dollars. that will get rid of yuor pre cats. and then piping from there til the end of the car will be about 150+ dollars.

[TWISTED II]

i have removed my cat and there really isn't anything wrong with it. it will be louder and you will me throwin a code. heres why. as you know, your car has o2 sensors, duh. well, your primaries are in your exhaust manifolds, and your secondaries are, 1 before, 1 after the cat. once you remove that, you have 2 options. either, install new spots for o2 sensors, and still throw a code cuz the one before the "cat area" will be reading the same as the one which would go after. how does one deal with this problem? easy, do what i did. i installed my primaries no problem. when it comes to the secondaries, you can buy o2 sensor simulators for about 50 bucks a pop. you plus these bad boys where the o2 sensor wire plugs into in your engine bay, and it will send a false signal to your ECU making it think your o2 sensor is working great and your in the clear. no cat, no o2 sensors, no SES light https://www.thegalantcenter.org/style_emoticons/default/smile.gif

Removing your cats honestly won't help a whole lot, except under FI...and still then, your car will stink really bad whenever you idle. It will be loud as hell if you take off your exhaust completley, and most states' fines for messing with your cats START at $2500. If they pull you over for loud exhaust, they will almost certainly get you on removing your emissions control devices.

Keep your cat on...I don't want my child growing a third leg because of the noxious fumes your car is pumping into the atmosphere. Take a few hp loss for the planet, man...[/hippie post] lol

[Supernova]

<div class='quotetop'>QUOTE(ScootinIntegra)</div><div class='quotemain'>Keep your cat on...I don't want my child growing a third leg because of the noxious fumes your car is pumping into the atmosphere. Take a few hp loss for the planet, man...[/hippie post] lol</div>

:laughing:

That made me chuckle. https://www.thegalantcenter.org/style_emoticons/default/tongue.gif

[Jet Black]

<div class='quotetop'>QUOTE(ScootinIntegra)</div><div class='quotemain'>Removing your cats honestly won't help a whole lot, except under FI...and still then, your car will stink really bad whenever you idle. It will be loud as hell if you take off your exhaust completley, and most states' fines for messing with your cats START at $2500. If they pull you over for loud exhaust, they will almost certainly get you on removing your emissions control devices. Â*

Keep your cat on...I don't want my child growing a third leg because of the noxious fumes your car is pumping into the atmosphere. Take a few hp loss for the planet, man...[/hippie post] lol</div>

No fair! Reelax gutted his cats. https://www.thegalantcenter.org/style_emoticons/default/biggrin.gif

[Wolfman]

What if you add High Flow Cats like Ripp does with their header system? I think that works pretty well although I'm still learning everythign able SDS so please correct me if I'm wrong. https://www.thegalantcenter.org/style_emoticons/default/biggrin.gif

[Wolfman]

According to RIPP, the headers also pass smog since quite afew SDS owners live in smoggable states and have passed with them still on(Ripp put the O2 sensors on but relocated them somewhat from stock.)

[TWISTED II]

i'm thinking once my exhaust is done....i will put a cat with flanges on, and when i'm racin, or wanna run the test pipe, all i hafta do is unbolt the cat, and throw back on a lil pipe with flanges. i'll do some dyno runs with and without cats, so maybe we can see if there really is a difference.

<div class='quotetop'>QUOTE(TWISTED!)</div><div class='quotemain'>i'm thinking once my exhaust is done....i will put a cat with flanges on, and when i'm racin, or wanna run the test pipe, all i hafta do is unbolt the cat, and throw back on a lil pipe with flanges. Â*i'll do some dyno runs with and without cats, so maybe we can see if there really is a difference.</div>
The difference is much more noticeable in boosted applications vs. NA apps. NA, you'll only gain like MAYBE 4 hp, if that. In FI, you can gain somewhere around 6-8 hp, if you're lucky. But you have to consider whether or not you want to pay the $2500 fee (minimum) for removing emissions control devices.

[Jet Black]

<div class='quotetop'>QUOTE(ScootinIntegra)</div><div class='quotemain'><div class='quotetop'>QUOTE(TWISTED!)</div><div class='quotemain'>i'm thinking once my exhaust is done....i will put a cat with flanges on, and when i'm racin, or wanna run the test pipe, all i hafta do is unbolt the cat, and throw back on a lil pipe with flanges. Â*i'll do some dyno runs with and without cats, so maybe we can see if there really is a difference.</div>
The difference is much more noticeable in boosted applications vs. NA apps. NA, you'll only gain like MAYBE 4 hp, if that. In FI, you can gain somewhere around 6-8 hp, if you're lucky. But you have to consider whether or not you want to pay the $2500 fee (minimum) for removing emissions control devices.</div>

2500$!!! Is that also apply to mufflers?

no no no....just emissions control devices. Like catalytic converters. Loud mufflers are like $25...haha https://www.thegalantcenter.org/style_emoticons/default/biggrin.gif

[Wolfman]

unless the cops don't give a $@#& then mufflers aren't a problem https://www.thegalantcenter.org/style_emoticons/default/laugh.gif

[Jet Black]

<div class='quotetop'>QUOTE(ScootinIntegra)</div><div class='quotemain'><div class='quotetop'>QUOTE(TWISTED!)</div><div class='quotemain'>i'm thinking once my exhaust is done....i will put a cat with flanges on, and when i'm racin, or wanna run the test pipe, all i hafta do is unbolt the cat, and throw back on a lil pipe with flanges. Â*i'll do some dyno runs with and without cats, so maybe we can see if there really is a difference.</div>
The difference is much more noticeable in boosted applications vs. NA apps. NA, you'll only gain like MAYBE 4 hp, if that. In FI, you can gain somewhere around 6-8 hp, if you're lucky. But you have to consider whether or not you want to pay the $2500 fee (minimum) for removing emissions control devices.</div>

LOL you had me scared for a second. After all no muffler= less back pressure = freer flowing = more hydrocarbons and stuff. But of course a cop wouldnt know that...hopefuly https://www.thegalantcenter.org/style_emoticons/default/biggrin.gif.

BTW: Auto-9 just posted a thread about some guy who switched from Cali to Fed spec and gained a whole 10 whp. Thats whats tickling my curiosity.

<div class='quotetop'>QUOTE(Wolfman)</div><div class='quotemain'>unless the cops don't give a $@#& Â*then mufflers aren't a problem https://www.thegalantcenter.org/style_emoticons/default/laugh.gif</div>
the only problem is, most cops do give a $@#& so you gotta be careful.

[Wolfman]

True I just haven't run into any here

[Jet Black]

<div class='quotetop'>QUOTE(ScootinIntegra)</div><div class='quotemain'><div class='quotetop'>QUOTE(Wolfman)</div><div class='quotemain'>unless the cops don't give a $@#& Â*then mufflers aren't a problem https://www.thegalantcenter.org/style_emoticons/default/laugh.gif</div>
the only problem is, most cops do give a $@#& so you gotta be careful.</div>

Well that really depends. As long as you dont go WOT around the popo its all good. The last 3 days I have come soooo close to being busted. The first day me and my friend were doing to some powerslides (I managed to do a 270 that would make the worlds greatest drifters jelous) in a culdesac (dont worry it was late, thus chances of children running out into the street to get their ball = 0), I was going to do one more, but a car started heading our way, so I decided I would wait to till it passed, and sure enough it was the Sherriff. Day 2 I raced a Gulf turbo, we slowed down because at the bottom of the hill was a stop light, and once again another cop, this time sitting off to the side of the road with his lights on us. I know he heard my car, only reason he didnt do anything was because he couldnt see us racing, till after we slowed down. And finally today, I was coming to a long stretch of road near my house, and I slowly let it creep up to WOT. I slowed down to make a left, and what do I see? About 5 cops in the parking lot. Each one of them mad dogging me. I think this is a sign that I should put my muffler back on, and stop flooring it everywhere.

[Reelax]

here's the story about my cats...

MPHUlimited used my car as one of the galant prototypes for their 3G dowpipe. i opted for them to add a high flow main cat replace the sotck piece (the 2 pre cats were ommitted by the downpipe. here's a pic vs. stock:

http://www.raniworld.com/RAAA/115-1512_IMG.JPG

well a few months after that i had the D3 CSK (chassis stiffenning kit prototype) installed and one of the bars was getting hit by the cat which sat about an inch lower than where the stocker used to sit because of the difference in bracketry on the dowpipe. well soon enough, the ceramic inside of the cat cracked, and for anybody that has had a internally broken cat, the sound is SO ANNOYING (sounds like there is sand and rocks in the piping that jump around like popcorn everytime you touch the throttle). so what did i do? straight pipe. problem is in CA you HAVE to have cats. not only will you b fined, the shop that did the werk for you will b fined as well and we're talking THOUSANDS each. so now i have what will at least pass the visual... i have a cat shell welded around internal straight pipe... even my O2 sensors look like they are plugged in correctly.

if and when my cars goes FI, the whole dp will b replaced w/ either headers w/ hi-fo cat (SC) or custom piping w/ hi-flow cat (twin turbo)... really, not having a main cat is not that much of an advantage.. the pre-cats are the real culprits in the the flow impedence... the main cat is not that restrictive.

one more thing... i foregot to tell you JET. not having a muffler is a fix it ticket... ( http://www.scrcla.org/california_excessive...noise_regul.htm ('http://www.scrcla.org/california_excessive_noise_regul.htm') Section 27150 VC requires that every motor vehicle subject to registration be equipped with an adequate muffler. There we no exceptions -- all vehicles must be equipped with a muffler, as defined in Section 425 VC. A turbocharger is not considered a muffler.) not as bad as not having cats but it is still a reason for them to pull you over. but you guys that have heard my car can confirm, my full exhasut system is louder than a stock system w/o muffler... it is LOUD at throttle but pretty calm at idle even w/ my dp, no cats, 2.75" piping and straight through race muffler w/ 5" tip.

one last thing... the cat was made to pretty much burn and evaporate the fuel that is not burned in the combustion chamber. to do this it needs to heat up... that's why cali spec 8g's have pre cats cuz these heat up much faster than the main cat so they work until the main cat hits operating temp. having said this, my car has no cats and you can really smell the fuel from my exhaust and you can actually see fuel spitting from my tail pipe as it's revved hard. i know, i know... not good.

[Fishboy55]

<div class='quotetop'>QUOTE(Jet BLaK)</div><div class='quotemain'>BTW: Â*Auto-9 just posted a thread about some guy who switched from Cali to Fed spec and gained a whole 10 whp. Â*Thats whats tickling my curiosity.</div>

I can tell you about that. I did almost the exact thing that Reelax did when I prototyped the US Spec RPW headers. The 10HP gain in Peter's post is probably close, especially with an intake and exhaust added. When I removed my pre-cats, the gain was incredibly noticeable. Unfortunately I didn't do a baseline. But with I/H/E, my WHP was at 161, so that's close to 10 at the wheels if you use 150WHP as the base, which I've seen as an average on here. We relocated the the O2 sensors so I didn't need a MIL eliminator. I passed emissions with the sniffer (the last year Maryland used it) with the headers and just my main cat installed.

[Mante]

What if you add High Flow Cats like Ripp does with their header system? I think that works pretty well although I'm still learning everythign able SDS so please correct me if I'm wrong. https://www.thegalantcenter.org/style_emoticons/default/biggrin.gif

There really is no point in upgrading to a hi flow cat if you have a cali spec galant. I know for sure that I4 comes stock with a hi flow because its has that annoying pre cat. I gutted mine, after all said and done had 5 more whp

[Wolfman]

Thanks for the info mante I stand corrected.

[MidNightRacing]

Removing your cats honestly won't help a whole .[/hippie post] lol

Exactly back when they first started puting cats on cars it would have helped, but now with all the advancement just of the make up of the cat it wont do anything(not to get into monitoring and other shit). Maybe on a 7g it give you like 1 or 2 hp.

[Mante]

Thanks for the info mante I stand corrected.

Nah its not to make you be wrong, its just I have already fallen down that stairwell so why not show you the elevator?

[Wolfman]

Yeah its all good thanks mante. I appreciate your knowledge