Fox X-pipe Vs H-pipe

Chad91gt · Mar 15, 2017

So I had some questions on what kind of exhaust I want to run. I Just had flow masters super44 installed with turn downs. I'm going to buy some shorty headers. But i want to know which exhaust is better x or h pipe. Since I'm in cali. I wanted to get one that will soot me best as far as performance and not worry about smog. And then when it's smog time have another setup I can install to pass smog. The pipes are bolt I right? I want to know what people prefer as far as performance and so they make a smogable set up and can just put in for smog that doesn't require welding. If my original exhaust is taken out it obviously can't be bolted back in. So technically I want 2 sets. One for performance that pretty much all the time and one when I need to smog. What do you guys think of this? Any ideas

Davedacarpainter · Mar 15, 2017

You can have both with the cats. They're not a big drag on your exhaust. Do a bit of research on cats and performance, I think you'll be pleased with the idea you'll be fine with just a catted exhaust overall. Less money and time on your back that way.

Honestly, imo, there's not much of a performance difference that I can find between the two.

Biggest thing seems to be the exhaust note. You want a raspier sound, use the x.

Though other more intelligent members may be able to tell you more.

FourEyed · Mar 15, 2017

I would do ceramic coated shorties with two hi-flow cats H pipe, keep the 44s and maybe add chromed exhaust tips.

Chad91gt · Mar 15, 2017

FourEyed said:
I would do ceramic coated shorties with two hi-flow cats H pipe, keep the 44s and maybe add chromed exhaust tips.

If I'm going for a performance exhaust what would be the upside to having 2 high flow cats ..since it won't pass smog because u would need 4 cara for visual smog. Is there a benefit to using 2 cats compared to using none and just straight pipe

Chad91gt · Mar 15, 2017

FourEyed said:
I would do ceramic coated shorties with two hi-flow cats H pipe, keep the 44s and maybe add chromed exhaust tips.

If I'm going for a performance exhaust what would be the upside to having 2 high flow cats ..since it won't pass smog because u would need 4 cara for visual smog. Is there a benefit to using 2 cats compared to using none and just straight pipe

Noobz347 · Mar 15, 2017

Moved to Talk section

Mustang5L5 · Mar 15, 2017

Chad91gt said:
If I'm going for a performance exhaust what would be the upside to having 2 high flow cats ..since it won't pass smog because u would need 4 cara for visual smog. Is there a benefit to using 2 cats compared to using none and just straight pipe

A modern 2-cat performance system would probably pass a sniffer, without the airpump. Modern cats are much more efficient than the 30 year old stuff still present on most stocking 5.0's. So just changing to a high flow 2 cat setup would pass the sniffer in some cases.

Problem, as you mention, is visual. Many of us don't have that issue, so we don't keep the stock parts around longer than necessary.

FoxMustangLvr · Mar 15, 2017

Chad91gt said:
If I'm going for a performance exhaust what would be the upside to having 2 high flow cats ..since it won't pass smog because u would need 4 cara for visual smog. Is there a benefit to using 2 cats compared to using none and just straight pipe

Having the 2 high flow cats will also help keep the tail pipe stink to a minimum. The fumes that come out of an o/r (catless pipe) can be less than pleasant to some people. It doesn't bother me at all honestly. Unbolting and reinstalling an h-pipe is simple and quick to do if it's really worth it to you to do once a year or couple years.

There are some exhaust clips on youtube from "xarmy" (I think that's his name) showing the different tones between x and h pipes. X pipes tend to be a little louder and h pipes tend to have a deeper sound. It's all about how you like your car to sound really.

Found the video

View: https://www.youtube.com/watch?v=6Ww2sHY8HB4

Deleted member 215073 · Mar 15, 2017

Why not run 4 high flow cats?

FoxMustangLvr · Mar 15, 2017

If you get caught by the police in Cali without catalytic converters on your car you'll be grabbing your ankles.

FoxMustangLvr · Mar 15, 2017

Q. What is the penalty for a violation of the law?

A. Catalytic converter falls under California anti-tampering law. The law is designed to prevent tampering with pollution control devices on California vehicles. The anti-tampering law is Vehicle Code Section 27156 and covers all pollution related systems and devices on a motor vehicle. A violation of this law may also include a parallel violation of California Business and Professions Code Sections 17200 and 17500. Judges usually impose penalty based on the severity of the offence and whether a repeat offender is involved, and a fine of up to $2,500 for each violation may be assessed, as well as some jail time.

Noobz347 · Mar 15, 2017

JMGlasgow said:
Why not run 4 high flow cats?

In an application like a Mustang, the two down-stream cats would do basically nothing. It's not like you cut emissions in half with each cat. The old catalytic converters were two-way. The newer high flow catalytic converters are 3-way.

2-way catalytic converters require a ton of heat to operate efficiently. A 14.7 AFR or leaner helps to provide that heat along with unburned hydrocarbons and some additional oxygen from the air-pump. These convert hydrocarbons to carbon dioxide and water and oxidize carbon monoxide to carbon dioxide.

3-way converters are not as efficient in this relatively lean environment. They're most efficient in a more rich and somewhat cooler environment. Their operating range is narrower and almost necessitates fuel injection in order to stay in that narrow stoichiometric range. These have the added task of splitting nitrogen oxides into nitrogen and oxygen.

So to answer the initial question: There would not be enough exhaust material and/or heat to create the conditions necessary to catalyze the exhaust in the second set of units. It wouldn't be any better than what it was coming out of the first set.

Deleted member 215073 · Mar 15, 2017

I just figured that since Mustangs had 4 cats on California models, that there would need to be 4 cats for the visual inspection.

The aftermarket exhaust I've seen with 2 cats have disclaimers saying not California legal.

General karthief · Mar 15, 2017

Good headers, keep the cats that are on there, the performance loss is next to nothing till you start pushing higher hp numbers, a good set of 2 1/2" mandrel bent tail pipes.
In a state like California if it has a carb number on it it is supposed to pass visual, you need to keep the pump with stock cats. It costs no hp to run.
I've read that if you put carb certified cats on then you can lose the pump, I don't belive it.
I've read about cali cars running 300hp cars with cats and full exhaust, I'm looking for the write ups but it was a while ago.

Noobz347 · Mar 16, 2017

JMGlasgow said:
I just figured that since Mustangs had 4 cats on California models, that there would need to be 4 cats for the visual inspection.

The aftermarket exhaust I've seen with 2 cats have disclaimers saying not California legal.

That is correct. It would need to have 4 cats, even if you could achieve better results with 2.

deathb4dismount · Mar 16, 2017

California is crazy. I was going to suggest the catted h pipe, I had one and passed sniffer in MA and even visual inspection. I guess they thought it was only supposed to have 2. I wouldn't mess around in CA though.

Chad91gt · Mar 18, 2017

So right now I have the super 44 flows with turn downs. I am going to put shorty headers on for sure. Should I keep the stock pipes with cats. Or can or should I get a after market x or h pipe with 4 .ca legal cats. Would i make more power or sound better

General karthief · Mar 18, 2017

A good set of headers, keep the stock h pipe,
The better sound is going to be subjective, 44's and turn downs are going to drone and drive you bat after a while. Your choice.

5.0Droptop · Mar 18, 2017

Thank god i live in the land of no inspections no sniffing of my exhaust. I love living where i can do what i want to my vehicles.

General karthief · Mar 19, 2017

no sniffing of my exhaust.

Now THAT is ct worthy
@Noobz347

Fox X-pipe Vs H-pipe

Chad91gt

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Davedacarpainter

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wonder how much it would cost to ship you a pair

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wonder how much it would cost to ship you a pair

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...all those nights we shared, and you're a dude??

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wonder how much it would cost to ship you a pair

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Fox X-pipe Vs H-pipe

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I love my Pimp

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Deleted member 215073

wonder how much it would cost to ship you a pair

Stangnet Facilities Maint Tech... Er... Janitor

Crap, didn’t realize my crotch was in that picture

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wonder how much it would cost to ship you a pair

...all those nights we shared, and you're a dude??

wonder how much it would cost to ship you a pair

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