Cat or not catted ?

HyperBlue#1 · 03-09-2017, 10:57 AM

Getting Kooks headers 1-7/8" long tube, i have a choice of either cat connectors or not. Any recommendations i'd imagine they will sound better without but are there any downsides for the cat delete ?

Stryfe · 03-09-2017, 11:42 AM

Quote:

Originally Posted by HyperBlue#1

Getting Kooks headers 1-7/8" long tube, i have a choice of either cat connectors or not. Any recommendations i'd imagine they will sound better without but are there any downsides for the cat delete ?

On my 98 Z28 (LS1), my headers sounded 1000x better WITH cats. Without cats it was so raspy. With high-flow cats it mellowed the rasp a ton.

enzia35 · 03-09-2017, 12:50 PM

I'm not no peace-nik hippy, but I'd still run cats.

gdgraph · 03-09-2017, 04:01 PM

I'm planning to do the cats when I go headers, It's louder without cats but I hear the sound quality goes down and it's raspy.

mariojmoe · 03-09-2017, 05:06 PM

Catless

Ventmaster · 03-09-2017, 05:36 PM

Direct injection engines are also able to be run much richer and still meet EPA guide lines. As a result when you remove the cats from the equation, you often get a serious raw gas smell

.

+1 for keeping your cats and if you're trying to get every pony in there- go for a quality high flow cat like Solo. They're a really nice 200 cell cat that improves flow over stock but will keep the gas smell and rasp out of your sound. Every part is stainless steel. Their online catalog isn't showing an offering for the 6thGen, but I'm sure it will soon. Contact Steve using the info here at the bottom of this web page- http://solo-performance.com/pe-camaro-ls3-std . I'm sure he can hook you up!

EFI Tuning · 03-09-2017, 05:48 PM

The standard HF cats offered with Kooks are more than adequate. Don't bother with the green cats. You will need to tune anyways.

We are offering free shipping right now on Kooks and a 10% off coupon code for a future order with us (good through April 2017).

Tim

Ventmaster · 03-09-2017, 06:02 PM

Thanks for posting up Tim.

Where can I find dyno results for switching to the Kooks 1-7/8" long tubes with the HF cats vs 2"x3", etc ?

Thanks you sir!

ULTRAZLS1 · 03-09-2017, 07:05 PM

From the graphs ive seen with teds comparison the 1 7/8 slightly beats the 2 inch all the way to peak but does not fall off as much after around 6k or so IIRC.

LiqTenExp · 03-09-2017, 07:17 PM

stick with cats, it sounds and smells better (had catless with kooks headers on 04 GTO but ordered their high flow cats afterwards)

EFI Tuning · 03-09-2017, 09:05 PM

Quote:

Originally Posted by Ventmaster

Thanks for posting up Tim.

Where can I find dyno results for switching to the Kooks 1-7/8" long tubes with the HF cats vs 2"x3", etc ?

Thanks you sir!

I think Ted did some dyno testing a while back. I don't have the link handy. I went 2" on my car only because I didn't want to wait 2 weeks for the 1 7/8" at the time. I personally am not overly concerned about midrange on the A8. On a M6 I definitely would not give up midrange for top end. The gearing needs all the help it can get.

USAFS197 · 03-10-2017, 02:47 AM

So you're saying that if we have an A8, getting 2" is perfectly fine? What about those of us who will never see a track but, want some extra umph?

Dfelux · 03-10-2017, 04:42 AM

I agree with HF cats. Had catless on my 5th gen and always smelled gas at lights. Gets old

gdgraph · 03-10-2017, 08:33 AM

I think 1 7/8" is the ideal option for a full bolt on and 2" is the way to go if you have future plans to do internals or go FI. That's if you are looking at optimizing the entire power band.

03-09-2017, 12:50 PM	#3
enzia35 Drives: '16 Garnet Red 1SS Join Date: Mar 2014 Location: College Station, TX Posts: 3,449	I'm not no peace-nik hippy, but I'd still run cats. __________________ '16 Camaro 1SS '18 Miata GT Gone: '01 Camaro, '14 Camaro, '90 Miata

03-09-2017, 07:17 PM	#10
LiqTenExp Drives: 2017 ZL1 Join Date: Jan 2017 Location: NJ Posts: 926	stick with cats, it sounds and smells better (had catless with kooks headers on 04 GTO but ordered their high flow cats afterwards) __________________ 2017 Camaro ZL1 Coupe M6 (847whp Dynojet on 93)

03-10-2017, 02:47 AM	#12
USAFS197 Drives: 2018 Audi TT RS Join Date: Jan 2014 Location: Navarre, Florida Posts: 1,915	So you're saying that if we have an A8, getting 2" is perfectly fine? What about those of us who will never see a track but, want some extra umph? __________________ 2018 Audi TT ▊RS 2.4X 0-60, 1.6X 60', 120+mph 1/8th, 4.XX 60-130, 150+mph traps on 255/35/18 R888R tires on the street (unprepped). 2019 Audi RS3 About as fast as the TT RS 2019 Camaro ZL1 1LE Sold 2018 Camaro SS 1LE Sold 2019 Corvette Z06 Sold 2021 Charger Hellcat Redeye Widebody Sold

03-09-2017, 10:57 AM	#1
HyperBlue#1 Drives: Hyper blue 1ss Join Date: Mar 2017 Location: Atlanta, GA Posts: 52	Cat or not catted ? Getting Kooks headers 1-7/8" long tube, i have a choice of either cat connectors or not. Any recommendations i'd imagine they will sound better without but are there any downsides for the cat delete ?

03-09-2017, 04:01 PM	#4
gdgraph Drives: 2016 Camaro 2SS Join Date: Jun 2016 Location: Arlington, VA Posts: 916 View My Garage	I'm planning to do the cats when I go headers, It's louder without cats but I hear the sound quality goes down and it's raspy.

03-09-2017, 05:06 PM	#5
mariojmoe Account Suspended Drives: C7 Z06 manual, 18 Zl1 manual, etc Join Date: Dec 2013 Location: Spring Texas Posts: 1,488	Catless

03-09-2017, 05:36 PM	#6
Ventmaster Drives: 2017 1SS 6spd Join Date: Jan 2011 Location: Utah Posts: 3,041	Direct injection engines are also able to be run much richer and still meet EPA guide lines. As a result when you remove the cats from the equation, you often get a serious raw gas smell . +1 for keeping your cats and if you're trying to get every pony in there- go for a quality high flow cat like Solo. They're a really nice 200 cell cat that improves flow over stock but will keep the gas smell and rasp out of your sound. Every part is stainless steel. Their online catalog isn't showing an offering for the 6thGen, but I'm sure it will soon. Contact Steve using the info here at the bottom of this web page- http://solo-performance.com/pe-camaro-ls3-std . I'm sure he can hook you up!

03-09-2017, 05:48 PM	#7
EFI Tuning Drives: 2016 Camaro SS Join Date: Oct 2016 Location: Mount Dora, FL Posts: 792	The standard HF cats offered with Kooks are more than adequate. Don't bother with the green cats. You will need to tune anyways. We are offering free shipping right now on Kooks and a 10% off coupon code for a future order with us (good through April 2017). Tim

03-09-2017, 06:02 PM	#8
Ventmaster Drives: 2017 1SS 6spd Join Date: Jan 2011 Location: Utah Posts: 3,041	Thanks for posting up Tim. Where can I find dyno results for switching to the Kooks 1-7/8" long tubes with the HF cats vs 2"x3", etc ? Thanks you sir!

03-09-2017, 07:05 PM	#9
ULTRAZLS1 Drives: 14 Silverado LTZ Z71, 16 Camaro SS Join Date: Nov 2009 Location: Jackson, Michigan Posts: 4,428	From the graphs ive seen with teds comparison the 1 7/8 slightly beats the 2 inch all the way to peak but does not fall off as much after around 6k or so IIRC.

03-10-2017, 04:42 AM	#13
Dfelux Drives: 2016 SS Hyper Blue Join Date: Jan 2016 Location: Tx Posts: 62	I agree with HF cats. Had catless on my 5th gen and always smelled gas at lights. Gets old

03-10-2017, 08:33 AM	#14
gdgraph Drives: 2016 Camaro 2SS Join Date: Jun 2016 Location: Arlington, VA Posts: 916 View My Garage	I think 1 7/8" is the ideal option for a full bolt on and 2" is the way to go if you have future plans to do internals or go FI. That's if you are looking at optimizing the entire power band.

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