Green Cats vs Catless for Weekend Car

[AZ18yote]

Huh? Your nose must not work cause ethanol definitely has a smell

E85 smells quite good with long tubes compared to straight pump. Almost sweet.

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[ICU812]

O/P you are in Cali. A car with cat delete you can smell from 50 yards away.
It is a 2500.00 fine per emissions part you removed, a tow and impound of car. It is not worth the extra 5hp you might get going catless. it isn't 1983 .
It only takes one officer to make your life a living hell.
Only you know if you are ok with that risk.
You are not going to pass the smog test anyways if those long tubes don't have an, e.o. number.
So unless this is a track car only.
I'd not go down this road. You will get popped and it will be very very costly.

 

[Marco_C]

Active exhaust, a resonator and E85 could probably mask it quite well.

That is what I was wondering. I do want to play it safe, but another side of me wants to get LTH and take the gamble.

O/P you are in Cali. A car with cat delete you can smell from 50 yards away.
It is a 2500.00 fine per emissions part you removed, a tow and impound of car. It is not worth the extra 5hp you might get going catless. it isn't 1983 .
It only takes one officer to make your life a living hell.
Only you know if you are ok with that risk.
You are not going to pass the smog test anyways if those long tubes don't have an, e.o. number.
So unless this is a track car only.
I'd not go down this road. You will get popped and it will be very very costly.

I hear ya. I was going to do LTH first, but now I am at an unsure state whether to continue or not. I am going to buy myself a supercharger and revisit this topic later for me lol. Appreciate everyone's opinions.

 

[Jackson1320]

Just curious, what’s your plan when you get caught at a red light with a cop behind you and he knows just enough that it shouldn’t be idling that loud and every other newer car he’s been behind doesn’t emit that smell? Now assume he’s had some training on spotting illegal mods. It’s a much bigger roll of the dice than anyone likes to talk about and the consequences of getting popped can be rough

My car is not loud. My car is just a little louder than it was stock. Stock mustangs with factory adjustable exhaust are way louder than me so no reason to look at me. I’m not going to drive around in a car that I can’t hear jack sh!t in. Could it happen sure. Will it happen no. The only cars I see getting anything are stupid kids racing through town. Also there’s no referee in this county. I don’t know what smell your talking about my exhaust smell like roses. Just because you are catless doesn’t mean you have to be loud or bring attention to yourself

 

[Jackson1320]

O/P you are in Cali. A car with cat delete you can smell from 50 yards away.
It is a 2500.00 fine per emissions part you removed, a tow and impound of car. It is not worth the extra 5hp you might get going catless. it isn't 1983 .
It only takes one officer to make your life a living hell.
Only you know if you are ok with that risk.
You are not going to pass the smog test anyways if those long tubes don't have an, e.o. number.
So unless this is a track car only.
I'd not go down this road. You will get popped and it will be very very costly.

There are no legal long tubes for the s550. Long tubes without cats can be closer to 50 Hp not 5. If the car is tuned correct you can not smell anything. It is true that you will not pass smog if the tech cares but some parts of California only tests cars when there’s a change of ownership. In those areas we just save the stock parts in case we ever sell the car. It is up to you too decide if it is worth it. If I did have to test every year I would not install LT’s. Test Every two years maybe I would swap them back and forth. They are not really a big deal once you have done it. To be honest I would probably use stock headers with the cats gutted and have a second set that are not gutted and swap them for smog tests

 

[ICU812]

There are no legal long tubes for the s550. Long tubes without cats can be closer to 50 Hp not 5. If the car is tuned correct you can not smell anything. It is true that you will not pass smog if the tech cares but some parts of California only tests cars when there’s a change of ownership. In those areas we just save the stock parts in case we ever sell the car. It is up to you too decide if it is worth it. If I did have to test every year I would not install LT’s. Test Every two years maybe I would swap them back and forth. They are not really a big deal once you have done it. To be honest I would probably use stock headers with the cats gutted and have a second set that are not gutted and swap them for smog tests

A car with cats and one without id 5hp. forget the long tubes. I was not commenting on that power gain.
And yes you can smell the exhaust even if you tune it.
Sure you can have a 2nd set of cats that are gutted, but why, 5hp on the street will not matter.
So unless the O/P is willing to pull the long tube headers and pipes, and install the oem parts and cats, and then reflash. to pass the smog test it is a no go.
I had my 2017 Chevy SS lost 5hp at power peak, and 3hp from 3400-5600rpm. with cats and without, no other changes. The cats are not an issue today, like they were 30+ years ago. no reason to remove them, on a street car you have to pass emissions. The o/p is in cali. he isn't sneaking long tubes and hollow cats through the test.
That is a pipe dream.

 

[Jackson1320]

A car with cats and one without id 5hp. forget the long tubes. I was not commenting on that power gain.
And yes you can smell the exhaust even if you tune it.
Sure you can have a 2nd set of cats that are gutted, but why, 5hp on the street will not matter.
So unless the O/P is willing to pull the long tube headers and pipes, and install the oem parts and cats, and then reflash. to pass the smog test it is a no go.
I had my 2017 Chevy SS lost 5hp at power peak, and 3hp from 3400-5600rpm. with cats and without, no other changes. The cats are not an issue today, like they were 30+ years ago. no reason to remove them, on a street car you have to pass emissions. The o/p is in cali. he isn't sneaking long tubes and hollow cats through the test.
That is a pipe dream.

Op is talking about installing LT without cats compared to stock exhaust because in California you have to have stock headers and stock cats to be legal. So from stock to catless LTs we are talking 50hp. I’m in California and Don’t have to have my car tested. I really have no smell from my exhaust. I know the smell you are talking about. The eye burning exhaust smell and I don’t have any of that. I agree that LT’s are not really worth all the BS that comes with them but if someone really wants them it’s not impossible

 

[Soulja4187]

Get some kooks headers with the green cats and then buy the catless tubes from kooks. I met a guy that would swap them out every so often. It will be expensive but if you got the money its no big deal.

https://kooksheaders.com/headers/he...atted-connection-kit-2015-2020-mustang-gt-50l

https://kooksheaders.com/exhaust/co...ed-connnection-pipes-2015-2020-mustang-gt-50l

 

[jmeiers]

Huh? Your nose must not work cause ethanol definitely has a smell

Stop it. You know what I meant in the context of this post. E85 exhaust “smell” is nearly non-existent compared to same car running 93 octane gasoline.

 

[ICU812]

Stop it. You know what I meant in the context of this post. E85 exhaust “smell” is nearly non-existent compared to same car running 93 octane gasoline.

Yup, today's pump gas stinks when it has not been treated/passed through a cat.
No matter the air/fuel ratio. 11 to 1 up to 17 to 1. you can smell it. And it isn't a smell like race fuel..

 

[Atlas1]

My car is not loud. My car is just a little louder than it was stock. Stock mustangs with factory adjustable exhaust are way louder than me so no reason to look at me. I’m not going to drive around in a car that I can’t hear jack sh!t in. Could it happen sure. Will it happen no. The only cars I see getting anything are stupid kids racing through town. Also there’s no referee in this county. I don’t know what smell your talking about my exhaust smell like roses. Just because you are catless doesn’t mean you have to be loud or bring attention to yourself

what exhaust are you running? if you have longtubes without cats, yes your car is loud. its night and day different than a stock mustang with active exhaust. no disrespect but you must have some serious hearing issues to not be able to tell the difference.
its great that you haven't had any legal issues where you live. but your experience alone is not what OP should be basing his decisions off of. don't get me wrong, i'm in full support of doing whatever you want to your car but to pretend that its only an issue for "stupid kids racing through town" is a lie and misleading to someone like OP who is coming here for advice.
when i got pulled over for my exhaust i was doing 25 in a 25 residential zone. in fact i saw the cop before he saw me and i was in 4th gear trying to make as little noise as possible. he even wrote i was going the speed limit on the ticket! there may be no referee in your county but your county is still in a state with specific laws and i can promise you there is a referee in that state. i guess if the cops where you live dont care and you dont have any intentions of leaving the county you might be ok.
we've established that your hearing isn't so good. apparently your nose doesn't work that well either. your exhaust smells likes roses? no, it smells like exhaust that hasn't passed through a set of cats.

There are no legal long tubes for the s550. Long tubes without cats can be closer to 50 Hp not 5. If the car is tuned correct you can not smell anything. It is true that you will not pass smog if the tech cares but some parts of California only tests cars when there’s a change of ownership. In those areas we just save the stock parts in case we ever sell the car. It is up to you too decide if it is worth it. If I did have to test every year I would not install LT’s. Test Every two years maybe I would swap them back and forth. They are not really a big deal once you have done it. To be honest I would probably use stock headers with the cats gutted and have a second set that are not gutted and swap them for smog tests

long tubes are not 50 hp. with a tune maybe lol.
not pass smog only if the tech cares? bullshit. the only way you're passing a smog test with longtubes is if the tech is willing to lose his job to help you out.
stop spreading misinformation about these issues because youre only doing a disservice to people like OP. again, i'm fully supportive of freedom and i think everyone should run headers as a middle finger to the man. but to pretend there is nothing to worry about is naïve at best. i was once young and in OP's shoes. listened to a few forum experts tell me that i should get some big power gains from headers and no cats. dont worry! only the ricers get hassled by the cops. the strangest thing was when i was in court for the illegally modified smog devices ticket and at the state referee, i don't remember seeing any of the people that were full of advice before, there to help pay the fines

 

[andrewtac]

for reference long tubes, with a magnaflow resonator, and stock mufflers (not active) is rather quiet; not much louder than it was with the complete stock exhaust

 

[ICU812]

what exhaust are you running? if you have longtubes without cats, yes your car is loud. its night and day different than a stock mustang with active exhaust. no disrespect but you must have some serious hearing issues to not be able to tell the difference.
its great that you haven't had any legal issues where you live. but your experience alone is not what OP should be basing his decisions off of. don't get me wrong, i'm in full support of doing whatever you want to your car but to pretend that its only an issue for "stupid kids racing through town" is a lie and misleading to someone like OP who is coming here for advice.
when i got pulled over for my exhaust i was doing 25 in a 25 residential zone. in fact i saw the cop before he saw me and i was in 4th gear trying to make as little noise as possible. he even wrote i was going the speed limit on the ticket! there may be no referee in your county but your county is still in a state with specific laws and i can promise you there is a referee in that state. i guess if the cops where you live dont care and you dont have any intentions of leaving the county you might be ok.
we've established that your hearing isn't so good. apparently your nose doesn't work that well either. your exhaust smells likes roses? no, it smells like exhaust that hasn't passed through a set of cats.


long tubes are not 50 hp. with a tune maybe lol.
not pass smog only if the tech cares? bullshit. the only way you're passing a smog test with longtubes is if the tech is willing to lose his job to help you out.
stop spreading misinformation about these issues because youre only doing a disservice to people like OP. again, i'm fully supportive of freedom and i think everyone should run headers as a middle finger to the man. but to pretend there is nothing to worry about is naïve at best. i was once young and in OP's shoes. listened to a few forum experts tell me that i should get some big power gains from headers and no cats. dont worry! only the ricers get hassled by the cops. the strangest thing was when i was in court for the illegally modified smog devices ticket and at the state referee, i don't remember seeing any of the people that were full of advice before, there to help pay the fines

Maybe it is me, but If I lived in that state, and a tech passed my illegal vehicle through smog, I would not be making that claim on the internet. But that is just me.
His mileage may vary.

 

[Performance nut]

I owned Kooks headers with green cats on my 2016. Despite what people say, it can be done without a tune and does have a power gain on a Ford tune. Though it is not as good cleaning exhaust as stock cats do. They have a minor smell. Idling for a short period will produce a noticeable (but not strong) smell. E85 may help with that but I didn't try it personally.

 

[jmeiers]

I’m full Kooks catless longtubes with true 3” out the back thru Borla active catback without the mid-pipe neck down an it does not smell on pump E85. I can run the car in the garage. Smells like popcorn without butter.

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