Opinions on hfc's

[Seubertm37x]

How's it going guys, I'm looking for opinions on what brand of high flow cats to purchase. What do you have on your m37x? I just reached 54k on my 2012 and I'm hearing a crackling/knocking noise. It's mainly coming from the drivers side cat, however you can hear it on both sides.. Time to replace and compliment my cat back exhaust

[ArmedAviator]

Cats shouldn't go bad unless you're running too rich. If you suspect a cat problem, identify the issue before replacing these parts.

[Ilya]

As for which HFC's...there have been a few discussed in this forum such as I believe Invidia, etc. If you search for HFC, you should be able to come across some threads.

[BlackCat81]

Cats shouldn't go bad unless you're running too rich. If you suspect a cat problem, identify the issue before replacing these parts.

Apparently you've never seen a melted cat from running lean.

[M37owner]

How could this get to point of damaging the cat?
The O2 sensors (before and downstream the Cat) should set the "Check Engine light" if your AFR is that far out.

[Seubertm37x]

How could this get to point of damaging the cat?
The O2 sensors (before and downstream the Cat) should set the "Check Engine light" if your AFR is that far out.

Yea I was thinking the same.. No cel/ses over here and aside from the noise car runs good.. Only hear it from the 1000-2000rpm range with the door or window open. No smoke or abnormal smells from the exhaust. my friend has a 2011 m37x also with the same noise, he didn't notice til I pointed it out on my car. Also in my search for more info on it led me to another forum where people with 2012 370z having same sounds coming from their cats as well.

[mikedamageinc]

I would check all of the heat shields for noise before buying cats. Get under there and hit the pipes with your palms real good all the way down, sometimes tricky to find but I've had that. A few stainless hose clamps and good to go.

[Seubertm37x]

As for which HFC's...there have been a few discussed in this forum such as I believe Invidia, etc. If you search for HFC, you should be able to come across some threads.

Found the threads thankyou

I would check all of the heat shields for noise before buying cats. Get under there and hit the pipes with your palms real good all the way down, sometimes tricky to find but I've had that. A few stainless hose clamps and good to go.

That's what I checked first I was under the car last night with 2 other people they suggested the same..everything's solid under there

[BlackCat81]

How could this get to point of damaging the cat?
The O2 sensors (before and downstream the Cat) should set the "Check Engine light" if your AFR is that far out.

You would have a check engine light on for sure if the cat was damaged due to running too rich or too lean. Sometimes the honeycomb inside them just breaks and rattles around.

[mikedamageinc]

That's what I checked first I was under the car last night with 2 other people they suggested the same..everything's solid under there

Make sure you check real good, I mean pound the exhaust all the way down with your hand every couple inches. I came real close to dropping the cash on new cats on my G and I checked one more time and found the rattle that I could only reproduce by hitting in one little spot, but was pretty noisy when driving.