Motown Cad

I have 158K and think my cats are just getting clogged. Had a bank 1 cat deficiency forever (only code) and am wondering why i don't just knock and scrape out all the honeycomb. Thoughts? Will the comp adjust or is it a huge no no.

NIKDSC5

iTrader: (10)

you can do it. Will have an engine light on until you have the rear o2's shut off.

isis

iTrader: (1)

In general I have read that a gutted cat will flow pretty much the same as an intact one due to the wonky shape of the now-empty chamber so I would expect no performance gain. Not that this applies to you.

Of course if your situation is a clogged cat, I would certainly try it. Worst case, you replace it, which is your only other option anyway. That said, with that many miles, I strongly advise that you put it up on ramps daily for a week and hit those bolts with PB blaster. And also get some bolt-outs for $40 at lowes because you are going to strip them anyway and need some serious force to get the cats off. I forget how many miles mine had when I took mine off but it was in the neighborhood of 20k and it was a straight up nightmare.

isis

iTrader: (1)

And yes, you'll have to deal with the CEL too. Spark plug non-foulers work, but use anti-seize on them and the sensor if you go that route, I shredded them and had to weld them shut and get new bungs put in when I decided to go to HP tuners and take them out.

ls1247

iTrader: (2)

Somebody also said that the car smelled pretty bad with gutted cats.

If you don't want to lay on your back messing with the bolts, call around and find a muffler shop that will work with manifold studs, take it there and have them break it all loose and or replace any that break. $80 well spent.

isis

iTrader: (1)

I have high flows in there but my subarus were catless and I loved the smell. Reminded me of my childhood and dirt bikes and whatnot. It's a sweet cancer-y smell.

+1 on getting it to be someone else's fight. That one is worth it. Those things sucked.

ls1247

iTrader: (2)

I overdosed on the smell working in bike shops...although castor 927 still smells good!

I was surprised how hard it was to find a shop that would actually replace a manifold stud if it broke...I lost 2 IIRC

jcollege

iTrader: (2)

Why guts the cats, just run test pipes?

isis

iTrader: (1)

Gutted cats require destruction and test pipes require fabrication?

cts-v 07ct

Do you have any other symptoms? I have changed o2 sensors on other cars and fixed that code. Start with the uppers. At that mileage it might need it anyways.

barrok69

If you ever get pulled over it still looks like you have cats to the naked eye and it's generally much easier to empty out existing cats than it is to fabricate new parts that fit as good.

hefftone

I had a clogged cat on my E36 m3....just one of the two. Holy ****, the car could not drive worth a ****...felt like I was towing a ******* buldozer. Car could not rev past 3k with the clutch in. I measure it with and exhaust back pressure gauge and that one side was pushing 15psi of back pressure at 2500 rpm.

I got the gauge off ebay....I actually have a brand new one I'd sell (had to order a second as I misplaced thendirsrt in the garage).