Are headers worth it over just going catless + catback

[Truekrry]

I’m starting to mod my 2018 gt , and we all know the big 3 mods, e85, intake, header combo . But I’m wondering how much hp am I losing out on if I were to just go e85 + catless , intake , instead of headers . Headers would be nice but the raspiness is crazy with aftermarket catback , and I’m looking at 2k+ with the install

So can I get away with just going catless while seeing similar gains or is this a mistake

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[Bob Lob Law]

It's the deleting of the cats that gives the raspiness...

 

[Truekrry]

But the catless headers will make it way louder than just going catless with a catback obviously. my question is am I missing out on a lot of hp by staying stock headers and just going catless

 

[2015 Silver GT]

Headers are not worth the money and you should also keep your cats. Not much gains in either and on the driver side the cat and factory header is one piece so you would need to remove it and cut it off. That’s just dumb if you ask me.

 

[K4fxd]

@engineermike Did some testing and if I remember correctly his made more power with cats. Probably tuning related but it's a head scratcher. If track only I would lose the cats for piece of mind. On the street I'd keep them. I can smell a catless car for a mile.

 

[SBR70.3]

Headers are not worth the money and you should also keep your cats. Not much gains in either and on the driver side the cat and factory header is one piece so you would need to remove it and cut it off. That’s just dumb if you ask me.

After trading in a Mustang with catted LTHs I 100% agree with this. The only reason to go to LTHs are if you are running FI and melt your cats. The $queeze i$nt worth the juice. Put that money into something else to improve performance.

 

[robvas]

Dyno of a cat delete from another forum member:

https://www.mustang6g.com/forums/threads/2018-gt-dyno-before-and-aft-mak-cat-delete.105082/

I just put my cats back on after almost a month...sounds so much better and smells way better...

 

[engineermike]

@engineermike Did some testing and if I remember correctly his made more power with cats. Probably tuning related but it's a head scratcher. If track only I would lose the cats for piece of mind. On the street I'd keep them. I can smell a catless car for a mile.

Definitely surprised the heck out of me. I made a dyno pull without cats (straight pipes), then swapped GT500 cats in and made another pull within the hour. It gained something like 15 hp IIRC. I'm guessing it was related to blow-through, either by losing charge or the effects of the lost charge on the O2 sensor reading. Either way, it's relevant data. I didn't try different cam timing to reduce overlap, but neither do the commercial tuners on catless setups.

 

[Truekrry]

So with all this being said I should keep headers and cats and just do intake/e85 until I’m forced induction

 

[2015 Silver GT]

Skip the intake and just do an E85 tune.

 

[Truekrry]

Skip the intake and just do an E85 tune.

ok thanks I should save a lot of money while picking up

Skip the intake and just do an E85 tune.

will I benefit from high flow cats enough to feel a difference or should I just stay stock cats, I see people blow their cats sometimes

 

[2015 Silver GT]

Your stock cats ARE high flow. Just let it go for crying out loud.

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