So lately I've been wondering if my aftermarket cat might be on it's way out. It's a Random Technology cat attached to my OBX header. I use an O2 simulator for the post-cat sensor, so there is no way for me to see if the cat is functioning. The car is getting progressively louder recently and the back of my car and white spoiler are always covered in a layer of metallic looking dust. I also am getting a slight buzzing rattle at certain RPMs...don't know if its a heat shield or the spring joint on the header, or the cat itself. I also detect a slight smell as if it did not have a cat...but its no where near as bad as when I was catless.

What are some ways for me to tell if its fried?? Thanks!

 

sounds about right for a bad cat.... can you remove the cat and shake it? if you look in, is the honeycomb all broken?

 

WHO NEEDS A CAT?

 

those sound like the same symptoms my CAT had when it went bad. I was smelling a burnt metal smell and could also hear the CAT rattling around. once we pulled the header out you could definitely hear the CAT when you shook it.

 

Why would you be running a O2 simulator and a cat?

 

Haha well if I didn't live in the wonderful state of California for most of my time...I'd prob say screw it and forget about it!! They are so rediculous there. And plus, it was just a tad obnoxious!

Because I originally had just a test pipe installed...but then later added the cat. Why bother drilling holes into the new cat to get the O2 sensor in it, when it might throw codes anyway. I just kept the o2 sim in place.


There's really no way for me to get the cat off and look at it, it's welded on . So assuming the cat went bad....what will happen if I keep running it with it on? **Besides hurting the environment**

 

Depends on what happens to the core. If the material collapses then flow is impacted. If it disintegrates then chunks blow out and they rattle around in the muffler. Both are pretty much worst case but can happen.

 

Grrrrrrrrrrrrrrrreat...hmmm now what.

So what if I were to get the stock cat cut of the stock header and welded on? Would it break down in 5000 miles as well?

 

Hard to say really but there are a lot of MINIs with 60-70-80 K miles on the OEM cat.
Some driven pretty hard.

 

Yeah, but I'm just wondering if the extra heat and flow from the OBX header will kill it too. Little pissed...its not like I had a cheap magnaflow cat either. Random Tech cats are supposed to be pretty good

 

Do you track the car or are you using header wrap or thermal coating?
That may add to the heat through the cat.
If you're not then the short life of the cat is odd.

 

One of my cats apparently had a breakdown when we brought my newborn daughter home from the hospital. She (the cat) took a dump right on the dining room table. Seal-point siameses can be sooooo jealous.

That feline was permanently relocated the next day.

 

I vote cut it out and put the stock cat in. You MAY be getting 2-3 extra HP from a high flow cat. Not worth the headache. I would definatly contact Random though and get the cat covered under warranty. Then sell it.

 

Ooh... Blake, i'm going to Steves tomorrow, are you still in AZ or did you get back to CA yet?

 

Yea! I'm about to leave right now to come back. What time you going? I'm free before 1...I'll go with you. PM me

 

damn... that was a short visit

 

How many miles do you have on that Random Tech CAT?
I'm running an OBX and one of those cheap magnaflow CAT's with the OEM sensor no problems.

 

Yeah, when I started searching around for opinions about Random Tech cats, I found plenty of gripes and complaints.....most of those ended with words like "you'd figure a cat that costs so much would last longer."

 

Everyone else has already mentioned the effects of a bad CAT... but since you're in a warmer area, let me add a bit of extra info...

I had a CAT go bad on my 94 Saturn. I took it into the dealer because it got really sluggish in warm weather. They misdiagnosed the issue and simply replaced the spark plug wires. Winter came and I had no problems because the CAT never got too hot. Once spring turned into summer, the car would just lose power upon acceleration. I was finally told the CAT was toast because you could hear the insides rattling when tapped (thank you Midas guy). After mulling over the cost to have the dearler or Midas replace the CAT only, I decided to replace the entire exhaust (header on back) at home. I bought a Random Tech CAT after much research and was very happy with it. I drove on it for almost 3 years before trading in the Saturn for my MCC.

I didn't have the bad smells or issues with sensors... but a bad CAT will make accelerating very unpredictable base on my experience. Good luck with getting a replacement CAT.

 

My dealer told me in May that my MCS CAT was bad because when they hit it they could hear bits rolling around in it. They started to look at it because I kept complaining of a exhaust rattle. They replaced the CAT.

Then in August I took my car complaining of the same exhaust rattle. This time they said it was my CAT again but that they wouldn't replace it. I took the car to an independent shop and found the noise was caused by the header's flex joint hitting a heatshield........

I replaced my entire header and CAT with a high-flow metallic one a week later due to my need for more power ...lol

 

Nope I have OBX header with stock cat - the cat hard 15,000 before I added the OBX and have 10,000 w/ the OBX.

No problems .