Best High Flow Replacement Cat?

[01Romanss]

I've read that the stock exhaust flow pretty well. Instead of the pain and cost of installing headers, is there a good choice of replacement CATS that would flow well and give more power and torque over just my stock exhaust?

Also, my local Ford dealer has told me that he doesn't mind warranty work on a car with a tune or gears. I have both. He did say he would not work on it if the CATS were missing.

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[JakeLethal]

I've read that the stock exhaust flow pretty well. Instead of the pain and cost of installing headers, is there a good choice of replacement CATS that would flow well and give more power and torque over just my stock exhaust?

Also, my local Ford dealer has told me that he doesn't mind warranty work on a car with a tune or gears. I have both. He did say he would not work on it if the CATS were missing.

Could probably just take your existing to an exhaust shop and have them hallowed out. So they're not missing and you get a little more of an aggressive tone.

 

[01Romanss]

Great idea! Will I set a code? Not sure if my Lund tune will take care of it. I've hear it would but of course the Lund rep couldn't tell me that without condoning doing something illegal.

 

[Performance nut]

Could probably just take your existing to an exhaust shop and have them hallowed out. So they're not missing and you get a little more of an aggressive tone.

But it will stink to high heaven. And if the shop isn't completely clueless will know that the cats don't work.

Depends on your threshold for custom work, there are options. Green cats are popular and Kooks has them as an option for their headers. I had these on my 2016, slightly increased smell with a moderate volume increase. Threw a CEL but I put O2 extenders on and it went away.

There is a European brand that is more expensive but has the best flow rate and weight than any other aftermarket cat I have seen. From what I have read, they do a good job cleaning up as well (European standards for air quality are more strict than ours). For those cats though you have to do your research and do some custom fabing as they don't sell specific cats for specific cars, they product length and diameter units that you have to spec your exhaust to. That is why most folks shy away from them: more work, more cost, and probably small gains.

 

[Andrew@Lethal]

I've read that the stock exhaust flow pretty well. Instead of the pain and cost of installing headers, is there a good choice of replacement CATS that would flow well and give more power and torque over just my stock exhaust?

Also, my local Ford dealer has told me that he doesn't mind warranty work on a car with a tune or gears. I have both. He did say he would not work on it if the CATS were missing.

Kooks

 

[WildHorse]

But it will stink to high heaven

Oh it ain't that bad. I can at least be in the garage for 5 mins before it gets annoying. My former 71 440 cid roadrunner would put you into tears in 37 seconds. And that was with 15 degrees of timing at idle and a stock idle circuit !

 

[WildHorse]

Kooks

Get a set of cats from a Tuatara. Rated at 1700 hp & passes emissions. Prepare to pay though haha.

 

[AZ18yote]

Oh it ain't that bad. I can at least be in the garage for 5 mins before it gets annoying. My former 71 440 cid roadrunner would put you into tears in 37 seconds. And that was with 15 degrees of timing at idle and a stock idle circuit !

Switching to corn smells quite lovely

 

[OnThree]

Kooks green cats are the only cats that actually really do something IMO

 

[WildHorse]

Switching to corn smells quite lovely

Unfortunately no pump E85 here.. either 5 gal pails or 55 gal drums. So I run MS109 on race day. Why do a bunch of upgrades when I can just pour it in and let the short terms trim it out & let the timing do it's thing haha.

 

[GregO]

is there a good choice of replacement CATS that would flow well

Not to many come close to HJS

https://www.fabspeed.com/blog/fabspeed-exclusive-hjs-cats-helical-valves/

 

[Performance nut]

Not to many come close to HJS

https://www.fabspeed.com/blog/fabspeed-exclusive-hjs-cats-helical-valves/

Yep but you need to size them yourself and custom fab your exhaust. No doubt they are good though.

 

[WildHorse]

RV6 Performance

All I see is civic/accord stuff. As for getting the HJS converter and reducers, any competent shop with a tig welder should be able to weld them together.

 

[K4fxd]

Get a 100 cell converter and weld it in.

50 cell are avalible but only in EU AUS.

 

[WildHorse]

50 cell are avalible but only in EU AUS.

What's the point then ? Might as well just gut the stock ones (with stock headers) or just put a couple 6 " bullet mufflers at the end of the LTH. Neither the 100 or 50 will pass a sniff test (pretty sure a 200 won't either, but I'm not a 100% on that).

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