Headers and sound

[Junkyard Dog]

If I were to install Kooks 1&7/8" long tube headers on my car, will it sound terrible?

I actually like the sound of my Dark Horse right now.

I read dismissive comments like, " Great way to add only 20 horsepower and make your car sound terrible at the same time."

Will they make my car sound terrible?

Will they make it appreciably louder? I do not really desire that, but a horsepower bump to be used during the long full throttle stretch at Michelin Road Atlanta from turn 7 to turn 10a (more of a long straight even though they claim there are "turns" 8 and 9 in that stretch) would be nice (from something like 45 mph to 140-145 mph with a stock Dark Horse, depending upon how deep you want to push your braking into that narrow 90 degree turn at the bottom of the hill - 10a).

I would appreciate reading comments from those who have installed these headers on an S550 or S650.

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[robvas]

It will be noticeably louder (and sound worse IMO)

 

[Q6543]

This is headers, stock resonator/active exhaust. I have since added a larger 3” muffler mainly to remove the 2-1/4 neck down and also it made it more quiet than stock.

 

[smurfslayer]

This is headers, stock resonator/active exhaust. I have since added a larger 3” muffler mainly to remove the 2-1/4 neck down and also it made it more quiet than stock.

Without cats?

 

[Q6543]

Correct.

 

[Junkyard Dog]

This is headers, stock resonator/active exhaust. I have since added a larger 3” muffler mainly to remove the 2-1/4 neck down and also it made it more quiet than stock.

Did you lose the active exhaust when you "added a larger 3" muffler?"

I had no idea the exhaust necked down to only 2.25".

That second clip was pretty quiet. Surprisingly so.

Just so I am clear, your exhaust is stock except headers, no cats, and a larger muffler? But you retained the stock resonator?

 

[Q6543]

In the 2 videos it is off-road headers into the stock resonator and active exhaust.

I have since these videos had the stock resonator/2 1/4 neck downs cut and replaced with the jones maxflow dual 3”

it still has untouched active exhaust from res/muff back

 

[Junkyard Dog]

In the 2 videos it is off-road headers into the stock resonator and active exhaust.

I have since these videos had the stock resonator/2 1/4 neck downs cut and replaced with the jones maxflow dual 3”

it still has untouched active exhaust from res/muff back

Ok, I am not following. I guess I do not know enough about the exhaust system (my car is too low to crawl under there and look), and you wrote that you "added a larger 3" muffler."

Is this an additional muffler, so now you have the resonator, a muffler, and the stock mufflers?

 

[Junkyard Dog]

So Google says it is 3" pipe.

What I am gathering from your post is that it gets reduced to 2.25" somewhere around the resonator?

M6G (this site for the S550) says the S550 is 2.75" with a half inch neck down to 2.25" at the "muffler bottle neck"
https://www.mustang6g.com/forums/threads/stock-exhaust-size-2-75-or-3inch.69447/
EDIT: this thread says 2.5" OD
https://www.mustang6g.com/forums/threads/size-of-the-stock-exhaust-for-gt.88680/

 

[Junkyard Dog]

I have since these videos had the stock resonator/2 1/4 neck downs cut and replaced with the jones maxflow dual 3”

 

[Junkyard Dog]

I never thought it would be so difficult to look up the exhaust pipe diameter on the internet.

 

[Steve@Lethal]

If you are running the factory catback, headers sound great with it and honestly what I recommend to most. Adding a resonator delete is the only other thing I would say can help but ye it will make it louder. We came out with this resonated H-pipe to help. keep tame the sound with headers and works great with the active portion
https://www.lethalperformance.com/l...ipe-2015-2026-ford-mustang-gt-dark-horse.html

Catless will make it louder than not but if you plan on boosting it, catless or GREEN cats are recommended.

If you do decide to get some, let me know if I can help as we stock KOOKS castless headers.
https://www.lethalperformance.com/l...it-2015-2025-mustang-gt-5-0l-1151h412-lp.html

 

[Q6543]

In the 2 videos I posted, it is headers, stock resonator stock catback.

the OEM and aftermarket headers have the 2 1/4 neck downs. The OEM resonator and 2-1/4 neck downs were cut out and the jones maxflow dual 3” was welded in where the OEM resonator was

your OEM exhaust after the cats goes to dual 2-1/4” pipes into the resonator, then back to 2-1/2 factory active exhaust pipe

2.75 is in GT500s and GT350s, you were in a GT350 sub forum

 

[drive_55_not]

I never thought it would be so difficult to look up the exhaust pipe diameter on the internet.

The factory exhaust is 2.5" ... It has 2.25" neck downs going into/out of the suitcase and around into the mufflers IIRC. That isn't a power robbing restriction on a NA car.

I have the Lethal/Kooks O/R headers with Factory connect elbows,

The Headers have a 3" collector with an elbow that necks down to 2.25" to connect to the factory suitcase.

Kooks Factory connect

I was going to swapout the factory suitcase with a couple 3" bottle resonators with a 2.5" connection but my welder took a dump and I'm too lazy to buy another one, Plus I'm getting too old to werk on this thing ,

Plus 2, IMVHO, the factory suitcase doesn't sound bad in sport and track modes.

Going WFO in Quiet and Normal Modes does sound like a Honda with a fart can , Quiet Mode sounds especially Ass Bad.

I leave mine in Sport mode 99% of the time and it's not too loud inside the cabin, behind the car is a different story, It is Loud.

Track Mode is a different beast, Going from Sport mode to Track exhaust you can hear the exhaust get noticeably deeper at idle and going WOT, It's Loud on Steroids.

As far as power, My car trapped 123.5mph on the stock exhaust and stock tune in 50 degree air, It's trapped 124.5 with the LT's so they pretty much net the same 20hp the Gen3's gained from LT's.

The LT's and a tune do add quite a bit of low end torque which would be benificial on a road course.



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[beefcake]

Running the factory Cat back will keep it more tame let me know if I can help get you setup with a set of Headers feel free to shoot me a message

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