Catalytic Converters?

[slapthefunkyfou]

Today I went to get my safety and emissions test done to renew my registration. I did not tell them that I had hollowed out my catalytic converter (it got clogged with mud last year) because I'm running short on money and I was just hoping that with some miracle it would pass. They tested it, and it passed the emissions test!!! With no cat!!! Of course it looks like there is a cat there, it's just hollow, none of that honeycomb stuff. The ex did wonderful on the high speed test with 63 ppm of hydrocarbons out of a maximum allowance of 220 ppm @ 2575 RPM. The low speed test wasn't quite as good with 141 ppm out of a maximum allowance of 220 ppm @ 784 RPM. That's pretty good considering my ex has over 200k miles and is 15 years old and missing the catalytic converter.

I talked to the shop manager and he explained a few things to me that I thought might be helpful to some of you. He said that the cat doesn't really affect the hydrocarbons that everyone is worried about. It makes a little bit of difference, but I guess not enough to make it fail the emissions test. He told me that the main things that control your emissions is the spark plugs, wires, cap and rotor (if your vehicle has them, explorers don't), pretty much all the things that control the spark in the engine. The hotter the spark, the more of the hydrocarbons get burned away. Of course, the air/fuel mixture makes a big difference also.

Well, I just thought that was a little wierd.

 

[TheFox88]

No its perfectely reasonable, the more complete burn you get out of the gas, the less unburned hydrocarbons there will be in the exhaust. The spark plugs, etc. have a lot to do with a complete burn.

 

[metstalker]

just goes to show you the cats dont make that much difference..... so to all those people who complain "your polluting my air" its not the case

 

[mikehawk]

How come the exhaust smells different w/o cats?

 

[SuperEx91]

The honeycomb stuff in the converter is a chamical that burns(?gets rid of, dont know technical term) any excess gas that does not get burned in the cylinder. If your vehicle is running good, it shouldnt make much of a difference in the smell. but if it is not running good(needs a tune-up), you can smell unburned gas that made it out of the cylinder with the converter removed where-as if it is installed, the converter would get rid of the excess gas.