Headers -> stock cat back?

04DetroitLS · 10-24-2022, 06:07 AM

Just out of curiosity (and after seeing a ton of ooopps my car is too loud threads), I was wondering if anyone had left the stock cat back after installing headers (either with or without cats). If so, how was performance/how loud was it?

KingLT1 · 10-24-2022, 08:24 AM

It works fine...stock muffler doesn't sound the best catless. Will need some resonators or high flow cats.

jdmartin04 · 10-24-2022, 09:25 AM

Quote:

Originally Posted by 04DetroitLS

Just out of curiosity (and after seeing a ton of ooopps my car is too loud threads), I was wondering if anyone had left the stock cat back after installing headers (either with or without cats). If so, how was performance/how loud was it?

I've seen quite a few members say that they think the stock NPP with headers is the best sounding combo there is... this is the route I plan to take - LT's into the stock NPP.

04DetroitLS · 10-24-2022, 09:39 AM

I just picked up a set of LTs and was planning on using stock cat back, debating on if I should use the cats that came with or not... I personally like the way the stock npp sounds, plus I actually like my neighbors

jdmartin04 · 10-24-2022, 01:27 PM

Quote:

Originally Posted by 04DetroitLS

I just picked up a set of LTs and was planning on using stock cat back, debating on if I should use the cats that came with or not... I personally like the way the stock npp sounds, plus I actually like my neighbors

I would go with cats, personally. I would also try it with factory exhaust first, see how it sounds and if you still want louder, then you know you need to go aftermarket

WiggyB · 10-25-2022, 08:43 PM

Nothing is louder when you going balls to the walls than the LT headers /w high flow cats. I have had many tell me that with my setup and a few have full exhaust done from headers back. I love the setup on my car won't even bother spending that kind of money just for a sound it has to give me more.

arpad_m · 10-25-2022, 09:59 PM

Quote:

Originally Posted by 04DetroitLS

I just picked up a set of LTs and was planning on using stock cat back, debating on if I should use the cats that came with or not... I personally like the way the stock npp sounds, plus I actually like my neighbors

I have Kooks LT headers, high flow green cats and the stock NPP exhaust. This setup gives the car a perfect Jekyll and Hyde sound, cruising in tour mode is still pretty decent and neighbor friendly, even warm starts are not overly loud. On the other hand, garage cold starts wake the dead and the car is an absolute roaring lion at WOT, as it should be.

One thing I will say is that the exhaust note is a bit raspy even with cats, not as refined and somewhat subdued as, say, a Borla NPP exhaust. It is basically a much more brutal "rendering" of the stock LT1 sound canvas.

ST1LE · 10-26-2022, 11:51 AM

Quote:

Originally Posted by 04DetroitLS

I just picked up a set of LTs and was planning on using stock cat back, debating on if I should use the cats that came with or not... I personally like the way the stock npp sounds, plus I actually like my neighbors

I cannot think of a single reason to not use the High Flow cats.

Kmeleon · 10-26-2022, 12:48 PM

Quote:

Originally Posted by ST1LE

I cannot think of a single reason to not use the High Flow cats.

If you track it.... From what I've read the cats melt down from the constant WOT and high rpms??

ST1LE · 10-26-2022, 12:57 PM

Quote:

Originally Posted by Kmeleon

If you track it.... From what I've read the cats melt down from the constant WOT and high rpms??

I'm not aware of cat issues on non-boosted cars.

Kmeleon · 10-26-2022, 04:44 PM

Quote:

Originally Posted by ST1LE

I'm not aware of cat issues on non-boosted cars.

Maybe I heard incorrectly then.

ST1LE · 10-26-2022, 04:50 PM

Quote:

Originally Posted by Kmeleon

Maybe I heard incorrectly then.

Even the ZL1 owners that mod their cars to very high HP numbers and blow out the Kooks Green Cats, they don't melt the cat, the cats just deform inside due to pressure.

Again, I have seen a lot of cat complaints and issues but never one from an NA build. Not saying it isn't possible, just never seen that myself.

There are some great builders and tuners on here, hopefully one of them will chime in.

6spdhyperblue · 10-26-2022, 07:24 PM

Quote:

Originally Posted by ST1LE

I'm not aware of cat issues on non-boosted cars.

Does that include COT off?

Bwaahhh · 10-28-2022, 09:10 AM

I am planning on doing Kooks LT Headers to Kooks green cats to stock NPP.

Hard to find this EXACT setup on youtube.

Anyone have sound clips or close to GA?

10-24-2022, 06:07 AM	#1
04DetroitLS Drives: 2022 LT1 Join Date: Sep 2022 Location: FL Posts: 92 View My Garage	Headers -> stock cat back? Just out of curiosity (and after seeing a ton of ooopps my car is too loud threads), I was wondering if anyone had left the stock cat back after installing headers (either with or without cats). If so, how was performance/how loud was it?

10-24-2022, 08:24 AM	#2
KingLT1 Drives: 2016 1SS NFG A8 Join Date: Aug 2017 Location: 46804 Posts: 6,800	It works fine...stock muffler doesn't sound the best catless. Will need some resonators or high flow cats. __________________ 2016 NFG 1SS A8 Options-2SS Leather/NPP Perf. mods-Whipple 2.9/Fuel System/Flex Fuel/103mm TB/Rotofab Big Gulp/Cat Deletes/Corsa NPP Per. times- 10.5 @ 137 w/ 1.8 60ft Full weight on 20's 1200DA

10-25-2022, 08:43 PM	#6
WiggyB Drives: 2022 Camaro 2SS 1LE Join Date: Nov 2021 Location: NC Posts: 275	Nothing is louder when you going balls to the walls than the LT headers /w high flow cats. I have had many tell me that with my setup and a few have full exhaust done from headers back. I love the setup on my car won't even bother spending that kind of money just for a sound it has to give me more. __________________ p1sc1 factory box w/ stage 2 intercooler, Lt4 fueling, JMS BAP, lt2 intake, kooks 1/78 longtube headers w/ h/f cats, alky meth kit, thpsi port injection

10-24-2022, 09:39 AM	#4
04DetroitLS Drives: 2022 LT1 Join Date: Sep 2022 Location: FL Posts: 92 View My Garage	I just picked up a set of LTs and was planning on using stock cat back, debating on if I should use the cats that came with or not... I personally like the way the stock npp sounds, plus I actually like my neighbors

10-28-2022, 09:10 AM	#14
Bwaahhh Drives: 2019 SS 1LE Join Date: Jun 2020 Location: Georgia Posts: 67	I am planning on doing Kooks LT Headers to Kooks green cats to stock NPP. Hard to find this EXACT setup on youtube. Anyone have sound clips or close to GA?

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