WHAT HIGH FLOW CATS TO GET

[harjotc22]

Hi everyone,

Im wanting to make my mustang a little louder and I already have a X pipe and a axleback but still want to go a little louder without breaking the bank and installing headers. I was looking at some forms and some people just go with a cat delete which i think would be too loud as I live in a HOA. I saw some people say going with highflow cats is kind of the middle of both so I am looking around and found some highflow cats but dont know which ones to get. I saw some speed engineering high flow cats for sale on facebook but don't know if they will last a long time.
I have also seen some people say that you cant just get any high flow cats because cheap ones might break. But i have nothing done to my car it is NA and i don’t plan on doing anything to it.

I just wrote a whole essay but to summarize my question what highflow cats should I get that wont be overly expensive and will last a long time? And can i get any high flow cat or does it have to be a specific one even though i am NA

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[harjotc22]

Also wanted to ask if I get a check engine light after I install them what do I do and can I drive the car with a check engine light or would it need to be fixed immediately?

 

[champamp]

https://www.gsportbygesi.com/

 

[2015 Silver GT]

Umm, you're going down a path where the juice is not worth the squeeze.

 

[drive_55_not]

The driver side cat is welded in so there's no easy way to replace that side either.


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[TXGTPig]

You're going to spend more time and money trying to add aftermarket cats to the stock manifolds than just going with Catted LTH. It's going to be way easier to change your axle back. What axle back are you currently running?

 

[harjotc22]

You're going to spend more time and money trying to add aftermarket cats to the stock manifolds than just going with Catted LTH. It's going to be way easier to change your axle back. What axle back are you currently running?

Right now i have the valved x force axle back. LTH would be way too loud which is why i was trying to find something in the middle.

 

[TXGTPig]

Right now i have the valved x force axle back. LTH would be way too loud which is why i was trying to find something in the middle.

Since you have a valved exhaust, you should be able to run it in "quiet" mode in the neighborhood with LTH and be completely fine. LTH are only "obnoxiously loud" with a straight-through type exhaust. Plenty of folks, and clips, of H/X Pipe, Catted LTH, and a valved exhaust that are pretty much stock quiet with the valves "closed". Hell, my '18 had catted LTH, X-Pipe, and a set of '15-'17 mufflers on it. It was quiet as a church mouse and hardly made noise under WOT.

 

[harjotc22]

Since you have a valved exhaust, you should be able to run it in "quiet" mode in the neighborhood with LTH and be completely fine. LTH are only "obnoxiously loud" with a straight-through type exhaust. Plenty of folks, and clips, of H/X Pipe, Catted LTH, and a valved exhaust that are pretty much stock quiet with the valves "closed". Hell, my '18 had catted LTH, X-Pipe, and a set of '15-'17 mufflers on it. It was quiet as a church mouse and hardly made noise under WOT.

But all the headers I see for sale are just headers i dont see and catted pipes with them. So i would have to buy the headers and the high flow cats to make it work? Wouldn't that be crazy expensive? And plus I would have to get a tune on it as well.

 

[TXGTPig]

But all the headers I see for sale are just headers i dont see and catted pipes with them. So i would have to buy the headers and the high flow cats to make it work? Wouldn't that be crazy expensive? And plus I would have to get a tune on it as well.

Yes and no. Texas Speed and Stainless Power offer an affordable set of LTH W/High Flow Cats. You can find the Stainless Power setup cheaper than the link I listed. It was just quick and easy. You don't need a tune for a header install; however, you won't get the same HP/TQ gains as a tuned Coyote with LTH. You could switch to the Corsa or Borla valved axle back and probably gain a decent amount of sound from that as well. Then sell the X-Force to recoup some of the cost.

https://www.texas-speed.com/p-10490-tsp-2015-mustang-50l-gt-headers-and-catted-connection-pipes.aspx

https://www.texas-speed.com/p-19430...mustang-gt-50l-1-78-long-tube-header-kit.aspx

 

[harjotc22]

Yes and no. Texas Speed and Stainless Power offer an affordable set of LTH W/High Flow Cats. You can find the Stainless Power setup cheaper than the link I listed. It was just quick and easy. You don't need a tune for a header install; however, you won't get the same HP/TQ gains as a tuned Coyote with LTH. You could switch to the Corsa or Borla valved axle back and probably gain a decent amount of sound from that as well. Then sell the X-Force to recoup some of the cost.

https://www.texas-speed.com/p-10490-tsp-2015-mustang-50l-gt-headers-and-catted-connection-pipes.aspx

https://www.texas-speed.com/p-19430...mustang-gt-50l-1-78-long-tube-header-kit.aspx

ok thanks! But if i have a check engine light wont the car run lean? Also so your saying just outting high flow cats is not a good option? If I were to do the LTH i would have to wait a bit and save but for the high flow i saw some kooks high flows that aren’t overly expensive and seem like they are sturdy enough for what I need

 

[TXGTPig]

ok thanks! But if i have a check engine light wont the car run lean? Also so your saying just outting high flow cats is not a good option? If I were to do the LTH i would have to wait a bit and save but for the high flow i saw some kooks high flows that aren’t overly expensive and seem like they are sturdy enough for what I need

Not necessarily. What typically happens when the CEL is triggered after a LTH install, catted or not, is that the rear O2 sensor is now seeing too much flow in the exhaust. So the ECU believes there is an issue with the cats and triggers the codes. This is a somewhat simple fix with something called a "defouler." Essentially, what it does is get the rear O2 sensors up and out of the exhaust flow, which in turn causes the ECU to think your cats are working properly.

You can go the aftermarket cat route on the stock manifolds if you want. While the cats may be cheaper up front compared to the LTH', paying a shop to install them is going to be very costly. That is, even if they will do it. I'd call a few local shops and ask them about doing this. I bet you get two answers. First and foremost, just a plain "no, we won't do that." The shops that will do it, will probably want at least $1K for installation and will probably want to supply the cats. Which will probably be at least another $1K. To replace the factory cats on the factory manifolds, they will have to remove the factory manifolds. Then they'll have to do quite a bit of fabrication to get the aftermarket cats installed. I've included a picture of the stock manifolds/cat setup to give you an idea.

 

[harjotc22]

Not necessarily. What typically happens when the CEL is triggered after a LTH install, catted or not, is that the rear O2 sensor is now seeing too much flow in the exhaust. So the ECU believes there is an issue with the cats and triggers the codes. This is a somewhat simple fix with something called a "defouler." Essentially, what it does is get the rear O2 sensors up and out of the exhaust flow, which in turn causes the ECU to think your cats are working properly.

You can go the aftermarket cat route on the stock manifolds if you want. While the cats may be cheaper up front compared to the LTH', paying a shop to install them is going to be very costly. That is, even if they will do it. I'd call a few local shops and ask them about doing this. I bet you get two answers. First and foremost, just a plain "no, we won't do that." The shops that will do it, will probably want at least $1K for installation and will probably want to supply the cats. Which will probably be at least another $1K. To replace the factory cats on the factory manifolds, they will have to remove the factory manifolds. Then they'll have to do quite a bit of fabrication to get the aftermarket cats installed. I've included a picture of the stock manifolds/cat setup to give you an idea.

ok thanks you! I will call some shops to see what they say and then see if i should go LTH or not. I also wanted to ask say a shop does say they can for cheap if I got them installed and used o2 spacers to remove the CEL it would be safe to use correct? Like it wouldn’t harm the engine in any way?

 

[TXGTPig]

ok thanks you! I will call some shops to see what they say and then see if i should go LTH or not. I also wanted to ask say a shop does say they can for cheap if I got them installed and used o2 spacers to remove the CEL it would be safe to use correct? Like it wouldn’t harm the engine in any way?

Yes, defoulers are completely safe to use and will not cause any harm. This is provided that the only codes (P0420/P0430) you get are from the rear O2 sensors.

 

[harjotc22]

Yes, defoulers are completely safe to use and will not cause any harm. This is provided that the only codes (P0420/P0430) you get are from the rear O2 sensors.

Ok great! Thank you!!

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