Drilling holes in catalytic converter... hack job?

[bugnut68]

A chick at our office has a friend who's a mechanic.  Her 4-runner To#¤ta sounded like dog sh*t the other day so I asked her about it.  She said that her friend drilled holes in the catalytic converter because it was clogged up or something.  Am I wrong in thinking this sounds like a hack job repair?

[Dave Rosique]

          I'm going to step out on a limb here and say.............. yes. Hack Job.



maybe even butcher..             

                             no, I know a butcher and he's not a hack, so please see above^^^

[stealth67vw]

Although this may be ingenious for rural Oregon, it's butchery anywhere else.

[kingsburgphil]

He did what?  

If the CAT is bad you replace it...period.   Preferably before it breaks up and clogs the muffler
and or the exhaust pipe.   Sheesh!!  Where did she find this "Carnecero".

[Rennsurfer]

A chick at our office has a friend who's a mechanic.  Her 4-runner To#¤ta sounded like dog sh*t the other day so I asked her about it.  She said that her friend drilled holes in the catalytic converter because it was clogged up or something.  Am I wrong in thinking this sounds like a hack job repair?

Yes, the biscuit (catalytic converter internals) gets dislodged from it's original position within the shell and moves to the rearward area, thus causing the exhaust gases to not flow freely. The end result is a crappy sounding engine/exhaust and even worse; a car that has almost no horsepower. You do NOT modify or drill holes to it. Calling it a hack job is putting it rather mildly. The best thing to do is first, determine that the plugged cat IS the problem. This is what test pipes are for. Or, take the internals out of the converter for test purposes. Then, go buy a Magnaflow or Dynaflow high performance one. They're cheaper than a factory new one and perform much better. I had this happen a year ago on my '82 BMW E21 and replaced it with a Dynaflow. Car ran GREAT, afterwards.

Besides all of the above, it's highly illegal in most states to modify (drilling holes) the cat. Your best bet is to stay safe and keep a working cat on the car... most modern engines are tuned to run with it intact.

[BeetleBug]

If the core is loose it is very easy to hear (like small rocks in a tin can) and the fix is easy. You unscrew the cat and then take a crowbar / iron bar and hack the core into smaller pieces so they fall out. Mount the "cat" back on to your exhaust. This again will be cause a win/win situation;

1) the car will use less fuel
2) the noise is gone
3) you will get more HP
4) you will polute less since a old cat has done its job a long time ago

Just do it.

Best rgs
BB

[Rennsurfer]

True, but don't get caught. Also, many cars won't pass the smog test in most states with a hollowed out cat. To each their own.

[BeetleBug]

I have smog tested both my Volvo and my Audi before and after I did this and the truth is that both cars got better results afterwards.

Best rgs
BB

[bugnut68]

In a rare occurrence, my instincts were correct.  I don't want to be the one to tell her, perhaps I should just email her the link to this thread.

Her car sounds like complete dog shit right now, which is what prompted the conversation in which I was enlightened to how it was, eh, "fixed."    This guy drives around in an old, black Ford Bronco (loud as hell, of course, and he drives it through neighborhoods as though he's an NHRA pro), and appears to aspire to be a professional "mudder" judging by the condition of his vehicle.  Lol.

[Rennsurfer]

I have smog tested both my Volvo and my Audi before and after I did this and the truth is that both cars got better results afterwards.

Best rgs
BB

Same here, with my '87 Volvo 245DL Estate 5spd. But it came up a little too rich afterwards. Sounded and ran better, though.

[Jim Ratto]

anybody think about how dangerous this is to driver/occupnats in car? The tailpipe of the car goes out back for a reason. She's insane to drive the car like this, SHE CAN DIE.

[bugnut68]

anybody think about how dangerous this is to driver/occupnats in car? The tailpipe of the car goes out back for a reason. She's insane to drive the car like this, SHE CAN DIE.

Well, she is a habitual cigarette smoker, so I'm sure she's probably not too concerned... sad thing is she's a pretty cool chick, and I would ask her out aside from two things: her general taste in men and I usually don't date people I work with, as a rule. 

[margaret]

hi guys my catalytic converter is bad and I cant afford a new one right now. Rather then just cutting it out like the mechanic suggested I heard I can just drill holes in it and move a hanger around to get the crap out. Will this work for a quick fix and how loud will it end up?  do i need a high performance catalytic converter? thanks for any help

[Rennsurfer]

hi guys my catalytic converter is bad and I cant afford a new one right now. Rather then just cutting it out like the mechanic suggested I heard I can just drill holes in it and move a hanger around to get the crap out. Will this work for a quick fix and how loud will it end up?  do i need a high performance catalytic converter? thanks for any help

Well, if you live in California... the laws have recently changed again so only certain converters can be used now. And, of course, they're more money than a year ago. I know this because I had my original converter on my '82 BMW E21 go bad. I was able to have a Magnaflow high performance one installed for only $150, Right after that happened, the new law came into play and the prices got really high.

Also, you don't want to drill holes and allow exhaust fumes to escape under your car. A sure recipe for disaster and rather uncomfortable for the people sitting in the cabin of your car. Bad idea all around. What typically happens on converters is that the biscuit inside gets dislodged and gets pushed to the back or the outlet of the converter body. Thus clogging the exhaust system and not allowing the gasses to flow/escape down their normal path through the the rest of the system. The car, then, gets to the point of being almost unable to drive. My BMW would only go to 25 miles per hour on the way to the muffler shop. It was that clogged.

I realize that you're on a budget, but the only way I'd recommend drilling would be to remove the biscuit (internal converter material) then plug up the holes with weld or epoxy. And only drive the car long enough to get it fixed the right way. Also, drilling the holes will make the car rather loud. Good luck with whatever you decide upon.