How loud will I be?

TheLPGuy · July 20, 2016

I have a 2015 Silverado 1500 5.3. Currently I have a side dumped cat back straight pipe. No muffler and no resonator. I was thinking of swapping out the California Cat for a "dummy" cat. Will it make a noticeable sound difference? I want it louder. I've always had loud vehicles. I'll post a picture to reference what I have deleted and what California cat I'm planning to switch out. Ideally I want a full 100% straight pipe but I can't currently do that where I live because of lease rules of not being overly obnoxious. The only reason I get away with what I have now is the landlord has the same truck as me and wants to mod his like I've done.

smrr1 · July 20, 2016

I doubt it will make much of a difference from what you have now. That thing has to be loud.

Silvern Sentry · July 20, 2016

There is no place in North America where a straight pipe is legal. Feel free to double check but I am 100% positive on this. I am also pretty sure you can get in trouble for selling a vehicle in CA without a CA cat, someone from CA can correct me maybe.

My 2c it just seems silly and a total waste. If you want louder in the cab you should get a Flowmaster Dual Out Dual side Super40+. This would allow you to remain incomplete compliance and probably make a much bigger impact for around 6-800 bucks.

Do what makes you happy though.

gamudslinger88 · July 20, 2016

I'm going to have mine removed and 3" ran back to the muffler. I have a borla xr1 and mandrel 3" tail pipe. It was quiet until I put a factory 6.2 tip on it and a K&N intake now the exhaust seems much louder. I'll still run the 3 to replace the factory 2.75 lead pipe and remove the Cali cat. Will it make a hill of beans? No but it's my fvcking truck and I'll do whatever I please. Lol. I'll keep y'all posted.

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TheLPGuy · July 20, 2016

There is no place in North America where a straight pipe is legal. Feel free to double check but I am 100% positive on this. I am also pretty sure you can get in trouble for selling a vehicle in CA without a CA cat, someone from CA can correct me maybe.

My 2c it just seems silly and a total waste. If you want louder in the cab you should get a Flowmaster Dual Out Dual side Super40+. This would allow you to remain incomplete compliance and probably make a much bigger impact for around 6-800 bucks.

Do what makes you happy though.

This cat isn't monitoring anything, it's basically a sound dampener. In some states (mine) this one is not regulated or looked at for inspection also I would keep it not get rid of it after changing it out.

Silvern Sentry · July 20, 2016

That is not what a catalytic converter does at all. Kind of scary you are chopping out parts and do not know how they function or their intended purpose.

See here: https://en.wikipedia.org/wiki/Catalytic_converter

A catalytic converter is an emissions control device that converts toxic gases and pollutants in exhaust gas to less toxic pollutants by catalyzing a redox reaction (an oxidation and a reduction reaction).

Dropping some science up in here yo!

TheLPGuy · July 20, 2016

I doubt it will make much of a difference from what you have now. That thing has to be loud.

It's not as loud as you'd think. It makes a good noise but dead quiet when when idling, and makes some noise at low cruising speeds. Like I said I am use to owning loud cars, I had a full true dual straight pipes 350z with 350whp and that screamed. Before that I had a evo with careless down pipe and muffler deletes also screamed. So maybe that's why the truck is quiet to me. My buddy has a early 2000s Silverado 2500 gas that's straight piped all the way and I love how loud it is. Either way I'll probably do the part I was asking about its only 40$ and I have the ability to change it back if I didn't want it any more.

TheLPGuy · July 20, 2016

That is not what a catalytic converter does at all.

See here: https://en.wikipedia.org/wiki/Catalytic_converter

A catalytic converter is an emissions control device that converts toxic gases and pollutants in exhaust gas to less toxic pollutants by catalyzing a redox reaction (an oxidation and a reduction reaction).

Dropping some science up in here yo!

I know what a catalytic converter does, but this one isn't hooked up to an o2 sensor is what I'm trying to get at. It's not monitoring it at all. They put it there for the extra fumes cleaning but it never needed to be added technically since they aren't monitoring it. The first two cats closest to the headers do all the work the third one is just added benefit from the factory.

Silvern Sentry · July 20, 2016

Ok that make more sense. Your OP make it sound like you were removing them entirely.

So the 3rd CA cat does a little extra but you have removed that since the O2 sensors are before and after the first 2. And no readings are taken after that CA one.

*Sorry not being from CA that was a bit confusing and was not aware there was no o2 sensor after it. I had figured O2 #2 would have been behind it.

TheLPGuy · July 20, 2016

Ok that make more sense. Your OP make it sound like you were removing them entirely.

So the 3rd CA cat does a little extra but you have removed that since the O2 sensors are before and after the first 2. And no readings are taken after that CA one.

*Sorry not being from CA that was a bit confusing and was not aware there was no o2 sensor after it. I had figured O2 #2 would have been behind it.

I understand, it is hard to get at lol. And I want to remove the 3rd one for the fact that it's not being used for anything. I was just seeing if it would make a noise difference like I hope it will. The part to replace it is only 40$ so I plan to do it either way because I have the ability to put it back on if need be.

Silvern Sentry · July 20, 2016

Sounds like you have a handle on it and are capable. Convinced me. I still have no idea how loud but I say give her a go and update us if you can always reinstall it easy enough.

TheLPGuy · July 20, 2016

Sounds like you have a handle on it and are capable. Convinced me. I still have no idea how loud but I say give her a go and update us if you can always reinstall it easy enough.

Going to order the part tonight and hopfully get it installed within the next couple weeks. Will update when it's done!

SouthPawCO · July 20, 2016

With your current setup, I doubt it will make hardly any noticeable difference. If you do notice a difference it will probably be more mental than anything. That thing has to be incredibly loud under WOT.

TheLPGuy · July 20, 2016

With your current setup, I doubt it will make hardly any noticeable difference. If you do notice a difference it will probably be more mental than anything. That thing has to be incredibly loud under WOT.

100% honest I've only hit wot twice and it's loud at that point lol