Cat vs Resonator

So I'm trying to figure out the components I need to make my cat back exhaust. Right now I have a 3 inch catless downpipe and stock cat back.

My initial plan was to have 3 inch catless downpipe that goes to a 3inch vibrant ultra quiet resonator, split into two 3 inch pipes and have two 3 inch vibrant mufflers.

I live in Cali so running no cats is sketchy, and I thought if I got pulled over and they found out I got no cat I would just get a state ref and I would put the car back to stock, no big deal. I recently found out that no cats if federaly illegal meaning they can impound my car indefinitely so I definitely am going to weld a cat into my downpipe.

I'm wondering if by putting a cat in will it act as a sort of resonator so I can just get a cat and two mufflers, instead of a cat, resonator, and two mufflers. Or am I going to still need a resonator to achieve my desired sound?

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A resonator, by and large, just quiets the car down, more specifically the frequencies that... resonate. Drone on the freeway is usually solved by putting a beefier resonator on your exhaust, followed by quieter mufflers.

It won't make a huge difference, resonator vs none, but I'd recommend getting one just so you don't get any drone on the freeway.

So its looking like I should probably get both a cat and a resonator. I thought maybe the cat would tone down some of the raspyness.

I like how the car in this video sounds with the resonator. It just takes out all the crackling and noise and makes it a pure tone.

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I live in Cali so running no cats is sketchy, and I thought if I got pulled over and they found out I got no cat I would just get a state ref and I would put the car back to stock, no big deal. I recently found out that no cats if federaly illegal meaning they can impound my car indefinitely so I definitely am going to weld a cat into my downpipe.

if you weld an aftermarket cat into your downpipe, it is still illegal modification to factory emissions system and they will impound your car if they really want to.

if you want to make legal modifications to your exhaust system it will have to be behind the FACTORY catalytic converter.

resonator is pointless. having a cat will quiet it down and smooth out the sound.

if you weld an aftermarket cat into your downpipe, it is still illegal modification to factory emissions system and they will impound your car if they really want to.

 

 

 

if you want to make legal modifications to your exhaust system it will have to be behind the FACTORY catalytic converter.

 

 

 

resonator is pointless. having a cat will quiet it down and smooth out the sound.

I saved all of my stock parts incase I do get state ref and need to smog it. I just don't want them to see no cat and just automatically impound it because its federally illegal, and thats the protocol.

But in all reality its a station wagon and its probably not going to get that kind of attention from law enforcement like a wrx would

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I get that it will still be illegal, but the only time I've seen people get impounded is when they are a d*** to the cop. They usually just give you a state ref knowing that most people will just sell there car out of state.

 

I saved all of my stock parts incase I do get state ref and need to smog it. I just don't want them to see no cat and just automatically impound it because its federally illegal, and thats the protocol.

 

But in all reality its a station wagon and its probably not going to get that kind of attention from law enforcement like a wrx would

 

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I mean not unless you have a loud ass exhaust lol. Didn't Cali pass a max decibel law for aftermarket exhaust?

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I mean not unless you have a loud ass exhaust lol. Didn't Cali pass a max decibel law for aftermarket exhaust?

 

 

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I have a full 3 inch exhaust with some mufflers, no cats, and it was way to loud, so I cut in a 16 inch resonator muffler. It dropped the loudness and drone significantly. Its not an air resonator, it has fiberglass or something in there to dampen the sound versus playing with frequencies like a normal resonator. The muffler style kills a lot more sound imo.

I used something like this

https://www.amazon.com/LCGP-Universal-Resonator-Performance-Straight/dp/B07Y1C7D87

I liked how it worked so well, that I have another 12" that I want to put in somewhere. I want to get it as close to stock level decibels as possible.

https://www.amazon.com/Universal-Resonator-Stainless-Performance-Polished/dp/B07VXNTR17

I'd say get a catted downpipe, and put in a resonator somewhere after, as well as the two mufflers at the ends. I'm not familiar with cali laws, all I know is they suck, so I don't know how much help I can offer. But when you go to 3" things get hella loud.

Also I wouldn't split into 2 full 3" for the mufflers, you may run into suspension problems, like if you run a bigger rear sway bar. A full 3" y pipe seems way to big and unnecessary, I don't see any performance gains by going that big after the split. 1.75" is what I would split it to, 2" tops. I think your mufflers are way to big and may cause more problems than gains.

I'd say get a catted downpipe, and put in a resonator somewhere after, as well as the two mufflers at the ends. I'm not familiar with cali laws, all I know is they suck, so I don't know how much help I can offer. But when you go to 3" things get hella loud.

 

Also I wouldn't split into 2 full 3" for the mufflers, you may run into suspension problems, like if you run a bigger rear sway bar. A full 3" y pipe seems way to big and unnecessary, I don't see any performance gains by going that big after the split. 1.75" is what I would split it to, 2" tops. I think your mufflers are way to big and may cause more problems than gains.

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