Longtube catted headers - Questions

[MustangMental]

A few questions,

1. I've read there are slight horse power/ torque gains from long tube headers, do these still happen with catted ones?

2. How is the sound with catted long tube headers compared to non-catted headers?

3. What is the risk of burning out the cats if you decide to supercharge the stang?

Thank you

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[LethalPerformance]

A few questions,

1. I've read there are slight horse power/ torque gains from long tube headers, do these still happen with catted ones?

2. How is the sound with catted long tube headers compared to non-catted headers?

3. What is the risk of burning out the cats if you decide to supercharge the stang?

Thank you

Hey there!
You will still see gains with catted headers - the more efficient ones traditionally yielding better gains.. (i.e. green cats).

The sound is more similar to stock manifolds than off road headers. You'll hear a difference at idle (usually even less loud than stock) but louder at WOT.

There is definitely a large risk adding boost to improper cats. They can clog and even blow up your motor. It depends a lot on the heat - tons of back to back runs running the risk higher than not.

We have a ton of cat options, but I would really urge you to look into green cats if boost is on the future table.

https://www.lethalperformance.com/k...2026-mustang-gt-dark-horse-5-0l-1151h432.html

 

[135Hoser]

1) Assuming you go with 1-7/8th or larger, and high flow cats, probably. But you can get a dyno to say anything. More gains to be had with a tune

2) Catless are a fair bit louder at all times. There's before/after clips on yt for S650 and S550.

3) 100% if you believe people on the forums. The stage 1 whipple tune has cat overtemp protection, and it's not afraid to use it, not that this will keep them from melting. Running crap gas which forces the ECU to dump fuel in to stifle knock also isn't good for any cat.

 

[robvas]

1. I've read there are slight horse power/ torque gains from long tube headers, do these still happen with catted ones?

Yes

2. How is the sound with catted long tube headers compared to non-catted headers?

Slightly quieter/cleaner sounding with cats than without. But still much louder than stock.

3. What is the risk of burning out the cats if you decide to supercharge the stang?

The risk is still high depending on how much power you are making and what kind of cats you get. Cheaper cats and lots of power isn't a good combination.

 

[Zig]

Yes



Slightly quieter/cleaner sounding with cats than without. But still much louder than stock.



The risk is still high depending on how much power you are making and what kind of cats you get. Cheaper cats and lots of power isn't a good combination.

At 14:1 how dirty is it gonna be? Is the trick keeping stoich?

 

[robvas]

At 14:1 how dirty is it gonna be? Is the trick keeping stoich?

Cleaner sounding. Not as much raspiness. Not as clappy. Especially at part throttle.

 

[MustangMental]

1) Assuming you go with 1-7/8th or larger, and high flow cats, probably. But you can get a dyno to say anything. More gains to be had with a tune

2) Catless are a fair bit louder at all times. There's before/after clips on yt for S650 and S550.

3) 100% if you believe people on the forums. The stage 1 whipple tune has cat overtemp protection, and it's not afraid to use it, not that this will keep them from melting. Running crap gas which forces the ECU to dump fuel in to stifle knock also isn't good for any cat.

When you say crap gas are you meaning 87 vs 93 or different gas stations that provide 93 gas?

 

[08mojo]

Hey there!
You will still see gains with catted headers - the more efficient ones traditionally yielding better gains.. (i.e. green cats).

The sound is more similar to stock manifolds than off road headers. You'll hear a difference at idle (usually even less loud than stock) but louder at WOT.

There is definitely a large risk adding boost to improper cats. They can clog and even blow up your motor. It depends a lot on the heat - tons of back to back runs running the risk higher than not.

We have a ton of cat options, but I would really urge you to look into green cats if boost is on the future table.

https://www.lethalperformance.com/k...2026-mustang-gt-dark-horse-5-0l-1151h432.html

What is the difference between the kooks with green cat you linked vs the HO green cats?

https://www.lethalperformance.com/k...2026-mustang-gt-5-0l-dark-horse-1151h442.html

My plan is to go with boost in the next year with a goal to make 700-750 whp. Is the HO version needed? Will either option bolt up to the stock catback?

 

[135Hoser]

go with the HO version 100%. both versions bolt up to the stock exhaust, you have to buy an adapter if you want to mate it to a 3" aftermarket exhaust.

HO cats are rated for the boost / extra HP, and will last longer than our factory cats when subjected to boost, allegedly.

 

[CliffClavin]

How’s the sound with high output Kooks? I don’t mind a little extra volume, but the uncatted are way too loud for me.

 

[Abilor]

go with the HO version 100%. both versions bolt up to the stock exhaust, you have to buy an adapter if you want to mate it to a 3" aftermarket exhaust.

HO cats are rated for the boost / extra HP, and will last longer than our factory cats when subjected to boost, allegedly.

H.O. Green cats FTW on Supercharged vehicles... Pay to play, baby!

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