ZERO cats

[mgmsleeper]

Do our cars NEED cats? Or can we go without em all and he car still can run great? I keep hearing about "back pressure" but have heard otherwise

[Chayton]

Do our cars NEED cats? Or can we go without em all and he car still can run great? I keep hearing about "back pressure" but have heard otherwise


Are you suggesting, that you condone the act of illegally modifying your vehicle? GASP :nono: :eek:








:D

jk, i have no idea. but wouldnt suggest it... with the whole.. illegal.. thing.

[fastblackmerc]

Does your state required them for state inspection?

I'd remove all 4 OEM cats and replace them with 2 hi-flow cats.

Unless you do this yourself you may not find someone to do this since it's against the law to "modify" the emissions system.

You do need some back pressure in the exhaust system for the motor to run properly.

"The catalytic converter plays a major role in the emissions reduction of a motor vehicle. The vehicle manufacturer has matched a specific catalytic converter to the vehicle to minimize emissions output. Both CARB and the EPA do not allow the replacement of a catalytic converter with non-exempt "high flow" performance replacement unit. In fact, it is technically not legal to even replace a converter unless it has been proven by technician to have failed, and then it can only be replaced with an exempt OEM equivalent unit. (However, enforcement of this requirement is difficult and is the primary loop-hole that allows the usage of so-called "high flow" catalytic converters. Many of these units are sold with the disclaimer as being a "race" component and are not intended for street use.) Due to the hundreds of vehicle models produced over the years, it is virtually impossible to determine by glancing under a car whether the converter is the original unit, a legal OEM replacement, or a non-legal aftermarket "high flow" performance unit. However, changing regulations require imprinting the exemption number, manufacturer code, and manufacture date, making it easier for technicians to determine the origin of the product and the intended application."

[mgmsleeper]

ZERO EMISSIONS HERE IN FLORIDA. One is clogged, got so hot last night it torched the heat shield or whatever you call it and heated up some more stuff so for now it's cheaper to cut her

[boatmangc]

If you take them all out your mufflers will sound like S#!t, ask me how I know.
Put 2 free flow cats in it.

[mgmsleeper]

If you take them all out your mufflers will sound like S#!t, ask me how I know.
Put 2 free flow cats in it.

Smh And i have borlas with their 4" tips. I'll see if the shop has some free flow cats. I gota get them off. Don't need another fire. I had to pull out the fire extuingsher

[babbage]

Misfire, and dumping raw fuel into the cats will also make them glow "cherry red"

Make sure you don't have that going on, or your new ones may get melted too.

[boatmangc]

If you take them all out your mufflers will sound like S#!t, ask me how I know.
Put 2 free flow cats in it.

[dohc324ci]

In Cali new cats must have a CARB EO# stamped on them.

[mgmsleeper]

OEM cats are bad. But I don't feel a misfire In the motor.

[mgmsleeper]

The cheapest shop in town which does the best work is charging 300$ to pull my cats and replace with high flow cats. I wasn't prepared for that. Only thing I can do is it them for now and hope it don't sound like crap.

[fastblackmerc]

The cheapest shop in town which does the best work is charging 300$ to pull my cats and replace with high flow cats. I wasn't prepared for that. Only thing I can do is it them for now and hope it don't sound like crap.

All four cats or replace the OEM four with 2 hi-flow cats?

BTW... cats usually just don't go bad. There is nothing mechanical inside.

If your cat(s) where getting hot enough to start a fire then that is indicative of another problem, usually dumping raw gas into the exhaust will cause a cat to get cherry-red-hot. Seen that plenty of times.

If cat(s) fail usually they breakup inside and block the exhaust flow.

Start the car and hold your hand by each tail pipe. If one side has a stronger flow than the other the cat(s) may be blocked on that side. But blocked cat(s) should not heat up enough to start a fire.

[justbob]

To answer your question, I have LT's, 2 1/2" X, 18" Magnaflows, tips out 1" and I cut out my resinators. The car runs the exact same as ever and you would not believe how quiet it is, unless you go WOT.

Now for the bad, when you idle for way too long or go WOT, it STINKS. (Remember the pre '74 cars?) Plus keep in mind I have a blower, 60# inj, and a BAP, therefor I push way more fuel.

I only went catless because of my budget and the kid in me wanted electric cutouts, which blew my budget. I have full intentions of adding a couple high flows next year to address the smell and to make her legal again. Also keep in mind my car does not see daily service, infact I am close enough in mileage per year to almost qualify for a exemption from emissions like I did on my Camaro.

This was posted live, in real time.

[justbob]

Almost forgot to mention my experience with awefull sounding mufflers as others have stated. VERY true! My once loved Flowmaster delta 50's that I have always praised had to be replaced immediately! I didn't even want to drive the car with chambered muffs, it was CRAZY raspy at 2000 RPM's and up, just embarrassing..

All this mention on raspy X pipes is just crazzy though, everyone speaks of this, yet I have zero raspy sound now, and zero drone. I have never liiked the sound of Magnaflows on anything, but felt it was my only choice for no change in sound throughout the RPM's. She is now maybe 10%??? Louder than a stock MM! Nice deep tone that stays consistant (like stock) no matter the RPM's, unless WOT like stated. At WOT, it is pure music, quality music, not noise.

I'll try and get some video soon, but quite honestly my cam corder sucks, and it always turns out muffled. I will try to find a day with very little wind and get a couple different in and out car vids.

This was posted live, in real time.

[Phrog_gunner]

Almost forgot to mention my experience with awefull sounding mufflers as others have stated. VERY true! My once loved Flowmaster delta 50's that I have always praised had to be replaced immediately! I didn't even want to drive the car with chambered muffs, it was CRAZY raspy at 2000 RPM's and up, just embarrassing..

All this mention on raspy X pipes is just crazzy though, everyone speaks of this, yet I have zero raspy sound now, and zero drone. I have never liiked the sound of Magnaflows on anything, but felt it was my only choice for no change in sound throughout the RPM's. She is now maybe 10%??? Louder than a stock MM! Nice deep tone that stays consistant (like stock) no matter the RPM's, unless WOT like stated. At WOT, it is pure music, quality music, not noise.

I'll try and get some video soon, but quite honestly my cam corder sucks, and it always turns out muffled. I will try to find a day with very little wind and get a couple different in and out car vids.

This was posted live, in real time.

You had me at muff. Can't wait to see/hear the vids

[mgmsleeper]

cats are gone car sounds great. no rasp don't even yell when i stomp it. sounds better regular driving & accelerating

ANYWAY i doubt its a misfire because i don't feel it in the car or motor. could have been dumping fuel but i wouldn't know why? maybe the tune? muffler man suspected they were clogged.

THE STORY (not a kill story just stating what happened): original owner purchased my MM while in his 50s babied the car from then till seeing the dyno in 07. after that it was more babying so the car has not been ran or pushed forever. so i figured a nice run to open her up wouldn't hurt. so i met a fellow MM owner we lined on a back abandoned street no traffic no people or anything keyword ABANDONED. raced, hit 140. Car pulled great ran great shifted great, let up off the throttle when i smelled it. pulled over popped the hood and seen the flame, i keep a fire extinguisher at all times so i got it and sprayed the car down. so maybe a clog caused it at that speed. i just drove 700+ miles in her from jville to Miami (80-90mph) steady the whole trip, driving around Miami and traveling back to jville with no issues at all.

now until i get high flow cats. can anyone recommend a good set? in Florida we don't have smog or emissions.

[D Rock]

Magnaflow 54306M - Universal Catalytic Converter Metallic Round 2.5" In/Out
Magnaflow
Try Amazon.com

[mgmsleeper]

Magnaflow 54306M - Universal Catalytic Converter Metallic Round 2.5" In/Out
Magnaflow
Try Amazon.com


mixing Magnaflow cats with Borla brand mufflers, resonators and 4" tips?

or do it not matter sound wise

[TFB]

Do high performance engine builders specify "needs x amount of back pressure"??? You guys know how the "needs some pack pressure" got started??? Basically it isn't so for a EFI vehicle... Back in the days of carbs increasing air flow at a given RPM would lean out the mixture so some back pressure was needed OR the proper procedure would have been increase the carb jet size to make use of the additional air flow... While the same can be true to a small extent for EFI, generally a clean exhaust system will improve performance...

Best example I can give is my '88 T-Bird with a Trick Flow headed 5.0... With 1 5/8" headers and stock exhaust system it's best time was 13.56@101... After trashing the stock stuff and installing a full 2.5" catless exhaust system with Flowmaster mufflers, it jumped to 13.11@105... That's approx a 40Hp increase, yeah you want back pressure...

[greggash]

I have NO cats at all
I have Kooks headers going into totally blown out Magnaflow mufflers

under light load its acceptable loudness wise

under a heavy load its like cutouts....loud like no tomorrow....but thats the fun part.

just keep an eye out for the law, and try not to be too loud in their presence.

My car is also Vortech supercharged, so extra loud!

[mgmsleeper]

Do high performance engine builders specify "needs x amount of back pressure"??? You guys know how the "needs some pack pressure" got started??? Basically it isn't so for a EFI vehicle... Back in the days of carbs increasing air flow at a given RPM would lean out the mixture so some back pressure was needed OR the proper procedure would have been increase the carb jet size to make use of the additional air flow... While the same can be true to a small extent for EFI, generally a clean exhaust system will improve performance...

Best example I can give is my '88 T-Bird with a Trick Flow headed 5.0... With 1 5/8" headers and stock exhaust system it's best time was 13.56@101... After trashing the stock stuff and installing a full 2.5" catless exhaust system with Flowmaster mufflers, it jumped to 13.11@105... Yeah you want back pressure...

i had never heard of "back pressure" until i got on the site. not saying others are wrong but i know some of what people say is "heard" and not proven. in your case you proved you were better out without. My car actually feels better the throttle is smoother, crisper and more responsive. i dont feel a performance loss at all.

[mgmsleeper]

I have NO cats at all
I have Kooks headers going into totally blown out Magnaflow mufflers

under light load its acceptable loudness wise

under a heavy load its like cutouts....loud like no tomorrow....but thats the fun part.

just keep an eye out for the law, and try not to be too loud in their presence.

My car is also Vortech supercharged, so extra loud!


lol :banana2::beer: no sound clip?

[greggash]

lol :banana2::beer: no sound clip?

When it stops raining I will go make a short movie

[mgmsleeper]

When it stops raining I will go make a short movie

ok ........... :beer:

[mgmsleeper]

Anything yet?

[LANDY]

Like I told you Chris no cats is better anyday. I still don't understand why people still run them on non smog states.

[MrBluGruv]

lol @ backpressure. Apparently the *****y stock manifolds provide enough if that is a genuine concern, here was mine without cats, with stock manifolds and some no-name mufflers:

1EOgKPFAib8

[mgmsleeper]

Like I told you Chris no cats is better anyday. I still don't understand why people still run them on non smog states.

They are adios. I'm trying to figure my next mod right now.

[ChiTownMaraud3r]

Clogged or not, park a hot car over tall dry grass..there's a video on youtube of a cop car that is destroyed when the dodge he's chasing goes off roading. The cop gets out and chases on foot..the guy gets away, cop comes back to fiery blaze of a crown vic.

Get the cat situation under control or it will damage your transmission oil, and eventually the tranny altogether.

[ChiTownMaraud3r]

And back pressure is not some made up thing. May not be the case as much on our Marauders, but on my towncar when it had a gaping hole in the exhaust, the car drove like ****...after repairing the leak throttle response felt like new again.

[mgmsleeper]

Clogged or not, park a hot car over tall dry grass..there's a video on youtube of a cop car that is destroyed when the dodge he's chasing goes off roading. The cop gets out and chases on foot..the guy gets away, cop comes back to fiery blaze of a crown vic.

Get the cat situation under control or it will damage your transmission oil, and eventually the tranny altogether.

Cats are gone that's more then enough control. I caught it before the meltdown

[MrBluGruv]

I fully believe that a loss of power due to a reduction in back-pressure in an exhaust system only comes from an engine set up or tuned to make efficient power and economy with an absolutely *****y exhaust system. The only time you would want any kind of exhaust obstruction (using that term loosely) is in a tuned exhaust setup, and even in that case the CFM flow potential of the exhaust is usually still very high and on top of that most street cars wouldn't see any serious difference between a near-free-flowing and precision tuned exhaust system, as most street engines don't flow nearly enough air to really utilize it.

[01LXHPP]

theres no such thing as needing backpressure, thats a complete false myth. Backpressure = bad, its about having correct exhaust velocity, or in simpler words, having a system thats perfect for your setup, not to big not to small

[SergntMac]

Ummm...I posted a lengthly examination of the "cats" issue several years ago. Not much new or different today, so I'll save my breath and your time. Do a search if you need more 411.

Meanwhile...For those of you who brag about not having to worry about cats or emissions in your home state due to lack of state law, got news for y'all. Cats (and other emission technology) is protected by FEDERAL law, enforcable in all 50 states. Thus, gather the attention of a state or local policer officer who feels it's his personal duty to enforce emissions, and all he has to do is notify the US Department of Agriculture and snitch on you. Sooner or later, the Special Agents will visit your home, they are very busy these days donchano...Oh, and BTW, they will have with them a tow tuck and an impound order, and suddenly you're playing in a whole different ball game. Just be aware, and try not to brag too much, or too loudly. They have been known to scan the .net for tips and clues.

Just ask me how I know? Sergntmac@aol.com, or, 312.401.1396.

Sorry to be a buzz kill, carry on gents and be safe.

[mgmsleeper]

Ummm...I posted a lengthly examination of the "cats" issue several years ago. Not much new or different today, so I'll save my breath and your time. Do a search if you need more 411.

Meanwhile...For those of you who brag about not having to worry about cats or emissions in your home state due to lack of state law, got news for y'all. Cats (and other emission technology) is protected by FEDERAL law, enforcable in all 50 states. Thus, gather the attention of a state or local policer officer who feels it's his personal duty to enforce emissions, and all he has to do is notify the US Department of Agriculture and snitch on you. Sooner or later, the Special Agents will visit your home, they are very busy these days donchano...Oh, and BTW, they will have with them a tow tuck and an impound order, and suddenly you're playing in a whole different ball game. Just be aware, and try not to brag too much, or too loudly. They have been known to scan the .net for tips and clues.

Just ask me how I know? Sergntmac@aol.com, or, 312.401.1396.

Sorry to be a buzz kill, carry on gents and be safe.


lol this goes from me fixing a real problem on my car to you talking about snitching and federal law & etc... seems like you're the snitch. my cats are gone WHO BRAGGED??????
you took time out your night for that? smh

MODS YOU CAN LOCK THIS UP!!!!!!!!!!!!
THE GOOD PEOPLE ALREADY HELPED ME OUT. THANKS FOR THE GOOD CHIMES

[MrBluGruv]

From all I've read all around, for 100% compliance sake with the law, even getting headers with a catted mid-pipe is illegal because you still modified the placement of emissions systems within the exhaust chain. I don't even ask why any more, I just assume the most senseless interpretation of an idea possible to be what the law is, with no wiggle room where said wiggle room could actually be beneficial. This is what happens when laws are written by people who know nothing about what they are legislating.

And with all that being said, I wouldn't exactly lay awake at night about it, but definitely don't go around bragging to everyone about your street-driven car being on the street without emissions control. And that would go for everyone, not just any one in particular.

[boatmangc]

I know this, as loud as my car is I will be putting a nice new set of free flows on when I get back from SSHS11!
So much for stealth.

[ctrlraven]

I removed my primary cats (rears where deleted years ago) and replaced with two Magnaflow 59956. They are 200 cell count, compact in size and can still take large displacement engines. Been working great for me.

http://img820.imageshack.us/img820/2232/dscf30071024x768.jpg

[cougar9150]

lol this goes from me fixing a real problem on my car to you talking about snitching and federal law & etc... seems like you're the snitch. my cats are gone WHO BRAGGED??????
you took time out your night for that? smh

MODS YOU CAN LOCK THIS UP!!!!!!!!!!!!
THE GOOD PEOPLE ALREADY HELPED ME OUT. THANKS FOR THE GOOD CHIMES

Mac wasn't saying anything negative just offering advice not to attract local PD attention. I know a few cops who would bust balls over something like that even here in Florida.

Mac said to email or call him if you wanted the scoop on how he knows. My guess is either him or someone he knows had what he explained happen to them. Mac has been on this site since the beginning and has helped a ton of people over the years and is just trying to offer sound advice.

Fly low because with my Cougar I got popped in Pinellas County back in 01 while speeding and had to add cats. Had to bring proof to the local traffic court that I had the work completed when I paid the speeding ticket.

Sent from my SPH-D710 using Tapatalk

[Black&Gifted]

You had me at muff. Can't wait to see/hear the vids

i want to see some vids of muff...audio not necessary.