Stock Cat-back Dark Horse with Catless Kooks Headers?

[NovaSayan]

I eventually plan to build a Whipple Dark Horse, and I know catless is the highly recommended option to avoid the cats from melting and clogging the engine. I don't really want to add headers since I prefer a deep sound without rasp and being overly loud, but I know if I plan to throw a blower on there, catless is the safest way to go. With that being said, does anyone have any videos of a catless Kooks header Dark Horse with the factory catback exhaust? Hoping the stock catback could muffle out some of the noise and prevent rasps, but haven't been able to find any clips of this specific setup.

Videos of catless headers 5.0s and the factory catback would still be helpful as well

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[smurfslayer]

Unfortunately I don't have a convenient video. I do have one but the upload fails.
It's just me cold starting in my garage on quiet mode. It jumps to about 105db, stays in the low to mid 90's at high idle, then settles to about 75-77 db just idling after it idles down.

Setting aside the noise issue for a moment, everywhere in NoVA requires emissions testing, which you won't pass without cats, not sure about headers.

I have the S/W headers, catless, stock suitcase and cat back. I'm out where the busses don't run and it's loud even for out here. Fortunately I have the active exhaust so I can keep quiet mode engaged. Cruising at 60-70 in 10th gear isn't horrible, but if you stab the throttle or lay into it gradually it's loud and raspy. My local shop is skeptical I can do anything to make it quieter. Maybe a less raspy sound or different tone, less db? IDK.

 

[Q6543]

Here friend

 

[NovaSayan]

Unfortunately I don't have a convenient video. I do have one but the upload fails.
It's just me cold starting in my garage on quiet mode. It jumps to about 105db, stays in the low to mid 90's at high idle, then settles to about 75-77 db just idling after it idles down.

Setting aside the noise issue for a moment, everywhere in NoVA requires emissions testing, which you won't pass without cats, not sure about headers.

I have the S/W headers, catless, stock suitcase and cat back. I'm out where the busses don't run and it's loud even for out here. Fortunately I have the active exhaust so I can keep quiet mode engaged. Cruising at 60-70 in 10th gear isn't horrible, but if you stab the throttle or lay into it gradually it's loud and raspy. My local shop is skeptical I can do anything to make it quieter. Maybe a less raspy sound or different tone, less db? IDK.

Yeah NOVA is pretty strict unfortunately but there are ways around it which I'm looking into. Sucks that it still has a decent bit of rasp but I'm glad to hear it's dailyable, thank you

Here friend

I've seen some of your posts with your setup, very solid! I believe you swapped out your resonator for the Jones resonator, which quieted it down a bit more, correct? By any chance, do you have any rev videos of your current setup?

 

[Sf22giants]

I live in Northern Virginia and have the setup you’re describing. The catless Kooks make the car significantly louder, especially with the exhaust in track mode. The revving is sorta loud… Under load, it’s incredibly loud.

I’ve got the kooks cats/connecting tubes sitting in a box for when it’s time to pass emissions. Otherwise, no cats the rest of the year.

 

[NovaSayan]

I live in Northern Virginia and have the setup you’re describing. The catless Kooks make the car significantly louder, especially with the exhaust in track mode. The revving is sorta loud… Under load, it’s incredibly loud.

I’ve got the kooks cats/connecting tubes sitting in a box for when it’s time to pass emissions. Otherwise, no cats the rest of the year.

This helps out a lot thank you! Pretty much the exact setup I’ll go for initially. I would like to reduce the rasp a bit more, maybe the Jones resonator could help.

This might sound like a dumb question but how do you swap out the cats and how long does it take? I assume you have to unbolt the cat back clamps, take the cat back off, then unbolt the headers from the cats?

 

[Q6543]

Not revving with the new set up, need to do a spring startup and drive soon.

but in quiet mode it’s definitely quieter than Stock cruising/part throttle… WOT the active kicks open so you really hear it rip then.

its so quiet in quiet mode I can actually hear my whipple … which very few people can say lol

 

[NovaSayan]

Not revving with the new set up, need to do a spring startup and drive soon.

but in quiet mode it’s definitely quieter than Stock cruising/part throttle… WOT the active kicks open so you really hear it rip then.

its so quiet in quiet mode I can actually hear my whipple … which very few people can say lol

That’s good to hear lol, do you have any clips at all with the Jones set up? I did see some of your quarter mile runs on your page. I assume the jones resonator has been able to hide more of the rasps that even the stock resonator wasn’t able to

 

[Sf22giants]

how do you swap out the cats and how long does it take?

The catted connecting tubes directly replace the catless tubes. The swap means unbolting the tubes from the headers at the ball flange (where the header meets the connecting tubes) and unbolting the other end of the connecting tubes where they meet the stock resonator. O2 sensors on the connecting tubes are also disconnected and swapped over. Installation is the opposite of removal.

This process takes about an hour. You absolutely do not need to remove anything between the resonator to the exhaust tips; all of that stays in place.

 

[SS2 GOTZ]

Waiting on parts delivery of my Kooks LTH and install. I decided to go with the high Temp Green Cats from Kooks as I don't want to mess with swapping out for emissions test. All reports are that these Cats will last and are designed for use with the Wipple. Expecting it to be loud, but not quite as loud as Cat less. If I were racing, I would definitely go Cat less, but this is just a fun/show car for me so I think this will be OK.

 

[smurfslayer]

I know the stainless works green cats are rated to 500hp; probably why the shop told me they would melt. If you put a whipple on with headers, you're going to easily bust 700hp --at the wheels--.
https://www.gsportbygesi.com/g-sport-emissions-systems-products

The big hp rated cats are big $$$.

 

[SS2 GOTZ]

This is what I went with, spec says Cats rated for 750 HP and up.

https://kooksheaders.com/products/1151h442

Not cheap, but then, I'm not skimping on my upgrades.

 

[Roninthedestroyer]

you have to be careful especially in Virginia they are strict on tinted windows and loud cars. My ex wife lives in Virginia so when I go to see my kid. I have to be on my best behavior even though my windows are tinted on my Shelby and exhaust is stock.
I live in North Carolina the police don't bother you for tint and loud exhaust.
If asked by a cop never tell him you have your in any other modes than normal.

 

[D/\rK•650]

Yeah NOVA is pretty strict unfortunately but there are ways around it which I'm looking into. Sucks that it still has a decent bit of rasp but I'm glad to hear it's dailyable, thank you


I've seen some of your posts with your setup, very solid! I believe you swapped out your resonator for the Jones resonator, which quieted it down a bit more, correct? By any chance, do you have any rev videos of your current setup?

Sounds awesome. BTW why do your taillights flash like that?

 

[NovaSayan]

Waiting on parts delivery of my Kooks LTH and install. I decided to go with the high Temp Green Cats from Kooks as I don't want to mess with swapping out for emissions test. All reports are that these Cats will last and are designed for use with the Wipple. Expecting it to be loud, but not quite as loud as Cat less. If I were racing, I would definitely go Cat less, but this is just a fun/show car for me so I think this will be OK.

Good idea, I know some are still kind of weary about those green cats, but I think the general consensus is that if you don't abuse the car too much it'll last a while. I'm contemplating the High Output Kooks Green Cats but man they're expensive, $2400 for the catalytic converter and pipes alone.

you have to be careful especially in Virginia they are strict on tinted windows and loud cars. My ex wife lives in Virginia so when I go to see my kid. I have to be on my best behavior even though my windows are tinted on my Shelby and exhaust is stock.
I live in North Carolina the police don't bother you for tint and loud exhaust.
If asked by a cop never tell him you have your in any other modes than normal.

Yeah, usually they don't pull you over for that but sometimes they might. Really depends on how much the cop wants to go out of his way to ruin your day. Never got pulled over for them even though I have tint. Never got pulled over for exhaust either but I haven't touched the headers on my car

Sounds awesome. BTW why do your taillights flash like that?

I think you're talking about @Q6543, but the reason his tailights are working fine. The reason the lights flashed is that LED lights can flicker really quickly to limit how bright they are, which the phone camera can detect while the human eye can't

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