Catalytic Converter Autopsy

[Weldangrind]

Spud's recent comments about catalytic converters prompted me to post these pics. This is a catalytic converter and air injection reactor (AIR) pump assembly from a 125cc Chinese dune buggy that belongs to member Sucksqueezebangblow. I had a spare exhaust pipe from a 50cc quad that I donated to get rid of the smog junk.

The first pic shows the whole assembly, and the arrow indicates the direction of exhaust flow. Bike and quad owners with catalytic converters will recognize this as the bulge in the exhaust header.

http://i158.photobucket.com/albums/t109/Weldangrind/Catalytic%20converter/CatalystandAIRPump.jpg (http://s158.photobucket.com/albums/t109/Weldangrind/Catalytic%20converter/?action=view&current=CatalystandAIRPump.jpg)

The idea behind the AIR pump is that it draws a bit of fresh air (usually from the air box) on the exhaust stroke, and sends it into the exhaust stream. You can see how the tube that connects to the exhaust pipe is on a slight angle, which helps to create the venturi effect. The inside of the valve is simply a reed valve (like on a two-stroke) that prevents exhaust from travelling backwards towards the air box.

http://i158.photobucket.com/albums/t109/Weldangrind/Catalytic%20converter/ReedValve.jpg (http://s158.photobucket.com/albums/t109/Weldangrind/Catalytic%20converter/?action=view&current=ReedValve.jpg)

Finally, this is a shot of the honeycomb catalyst within the bulge in the pipe. Yeah, that's not restrictive. :roll: The catalytic converter and the AIR pump aren't actually related, they just happen to be mounted near each other.

http://i158.photobucket.com/albums/t109/Weldangrind/Catalytic%20converter/Catalyst.jpg (http://s158.photobucket.com/albums/t109/Weldangrind/Catalytic%20converter/?action=view&current=Catalyst.jpg)

[sucksqueezebangblow]

that couldnt have been taken in your carport i can see the floor

[Weldangrind]

You suck. And it's not a carport, it's a shop. Learn some manners, or no more donuts.

[sucksqueezebangblow]

lol sensitive.......alright its a GARAGE but still way to clean....i dunno looks like a tim hortons table

[Weldangrind]

As part of your membership here, you're required to update us about the mods to your dune buggy WITH PHOTOS. Get on the stick man.

[lego1970]

Good post Weld.

From a guy with very limited knowledge on chemistry and or chemical engineering, ( I do know the melting point of chedder cheese and can cook a mean grilled cheese sandwich :P ) I have to say that I do find it very fascinating how the chemical engineers know how to coerce the atoms to bond in a way in which they desire based on a little metal and heat. Not to mention the abilty make a machine that can detect what the elements are in a certian gas. The gas spectrometer is an awesome machine. It baffles me that guys come up with stuff like that. Heck I get stumped on trying to balance my checkbook :?

[SpudRider]

Thank you for the tutorial, WaG. :) I've been told the exhaust pipe is double-walled around the catalytic converter. Is the entire exhaust pipe double-walled? How much heavier are exhaust systems which contain catalytic converters?

Spud :)

[Weldangrind]

On this specific cat, only the cat housing is double walled, and the cat / AIR pump assembly weighs about one pound. I doubt that the entire exhaust system on any China bike is double walled, aside from the cat.

[SpudRider]

No offense meant, but that catalytic converter and air pump are ugly! 8O The Chinese exhaust systems are notoriously heavy, and restrictive. :( I think the first task for any new Chinabike owner is to replace the stock exhaust system. ;)

Spud :)

[Weldangrind]

My thoughts exactly. Member sucksqueezebangblow reports that his kid's dune buggy woke up after ditching the smog junk.

[SpudRider]

My thoughts exactly. Member sucksqueezebangblow reports that his kid's dune buggy woke up after ditching the smog junk.
I believe! I'm amazed the engine can exhale at all through that nasty catalytic honeycomb. 8O

Honda is notorious for adding SMOG pumps to their engines; however, I don't think Honda ever resorts to catalytic converters. :roll: I was a happy man when I removed the SMOG tumors from my XR650L. ;)

The exhaust system on my Zong was very heavy, and highly restrictive. I can't believe I waited so long to remove it, and install an FMF Universal Spark Arrestor! :roll:

Spud :)

[Weldangrind]

I agree that the catalyst is terribly restrictive, but I don't think that the AIR pump (in this application) hurts peformance. In fact, the idea is that a burst of air will enter the hot exhaust stream to provide fuel to further burn any unburned hydrocarbons. That might make the folks at the EPA happier, but on a child's machine it's just another device to get in the way and break on a tree or a rock.

I had a similar device on an old four cylinder Chev when I was a kid, and the internal valve failed, which provided a steady stream of oxygen all the time. Every time I lifted the throttle to shift gears, BANG! Shortly thereafter was the first time I ever performed a smog-ectomy. :lol:

[SpudRider]

I agree that the catalyst is terribly restrictive, but I don't think that the AIR pump (in this application) hurts peformance. In fact, the idea is that a burst of air will enter the hot exhaust stream to provide fuel to further burn any unburned hydrocarbons...
Thank you for elaborating, Wag. :) Indeed, all reports I have read indicate the "air pumps" don't hurt performance. However, they certainly are ugly! :P

Spud :)

[FastDoc]

Good post Weld.

From a guy with very limited knowledge on chemistry and or chemical engineering, ( I do know the melting point of chedder cheese and can cook a mean grilled cheese sandwich :P ) I have to say that I do find it very fascinating how the chemical engineers know how to coerce the atoms to bond in a way in which they desire based on a little metal and heat. Not to mention the abilty make a machine that can detect what the elements are in a certian gas. The gas spectrometer is an awesome machine. It baffles me that guys come up with stuff like that. Heck I get stumped on trying to balance my checkbook :?

Creation is amazing. :D

The more I learn, the more degrees I accumilate, and the older (wiser?) I get the more I am amazed with Creation and the more certain I am of the Creator.

It's good that different people are blessed with different abilities. Some guy is a scientist and understands catalysts but can't fix his sink. The plumber makes quick work of the sink but can't fly a plane. The pilot flys fine but can't play golf. The pro golfer can't fix his Harley and so on...

[FastDoc]

No offense meant, but that catalytic converter and air pump are ugly! 8O The Chinese exhaust systems are notoriously heavy, and restrictive. :( I think the first task for any new Chinabike owner is to replace the stock exhaust system. ;)

Spud :)

Ugly indeed. We de-smogged the KLX's while we were at it, even though none of the plumbing could be seen behind the shrouds. Just knowing it was there.... :wink:

[FastDoc]

My thoughts exactly. Member sucksqueezebangblow reports that his kid's dune buggy woke up after ditching the smog junk.
I believe! I'm amazed the engine can exhale at all through that nasty catalytic honeycomb. 8O

Honda is notorious for adding SMOG pumps to their engines; however, I don't think Honda ever resorts to catalytic converters. :roll: I was a happy man when I removed the SMOG tumors from my XR650L. ;)

The exhaust system on my Zong was very heavy, and highly restrictive. I can't believe I waited so long to remove it, and install an FMF Universal Spark Arrestor! :roll:

Spud :)

I might be wrong but I think pretty much all street legal bikes run cats now. BMW, IIRC, started it in the 80's with the K bikes.

[FastDoc]

I agree that the catalyst is terribly restrictive, but I don't think that the AIR pump (in this application) hurts peformance. In fact, the idea is that a burst of air will enter the hot exhaust stream to provide fuel to further burn any unburned hydrocarbons. That might make the folks at the EPA happier, but on a child's machine it's just another device to get in the way and break on a tree or a rock.

I had a similar device on an old four cylinder Chev when I was a kid, and the internal valve failed, which provided a steady stream of oxygen all the time. Every time I lifted the throttle to shift gears, BANG! Shortly thereafter was the first time I ever performed a smog-ectomy. :lol:

I had that happen to me when I was an EMT driving a big Ford ambulance with a 460 back in the '80's. It detonated the mid muffler 8O . Thank God I didn't have a patient aboard would have scared him to death 8) .

My buddy Jimmy and I were between calls doing some top speed testing... :roll:

[lego1970]

Good post Weld.

From a guy with very limited knowledge on chemistry and or chemical engineering, ( I do know the melting point of chedder cheese and can cook a mean grilled cheese sandwich :P ) I have to say that I do find it very fascinating how the chemical engineers know how to coerce the atoms to bond in a way in which they desire based on a little metal and heat. Not to mention the abilty make a machine that can detect what the elements are in a certian gas. The gas spectrometer is an awesome machine. It baffles me that guys come up with stuff like that. Heck I get stumped on trying to balance my checkbook :?

Creation is amazing. :D

The more I learn, the more degrees I accumilate, and the older (wiser?) I get the more I am amazed with Creation and the more certain I am of the Creator.

It's good that different people are blessed with different abilities. Some guy is a scientist and understands catalysts but can't fix his sink. The plumber makes quick work of the sink but can't fly a plane. The pilot flys fine but can't play golf. The pro golfer can't fix his Harley and so on...


I would agree that age has changed my thinking. Sure drinking 8 days a week has probably altered my thinking over the years, but not much considering I've been drinking that way for 20+ years, yet my beliefs stayed pretty much the same for the first 15 of those 20 years and has really only changed over the last 5. Ok, I'm just joking on the "8 days a week". I've been wanting to use that line for....well, weeks :wink: .

Seriously though, I used to be somewhat atheist in my beliefs but as I get older, I tend to believe that there is some truth towards religions. While I'm not sold on any one particuliar religion, I am starting to think that there could be something else orchrestrating everything known to mankind. I also don't think my judgement is being clouded by other physicological events taking place in my body and mind. I think it's more of those :idea: "that makes sense" moments that have kinda swayed me more towards taking religion serious.

Sorry for hijacking your thread Weld. Kinda getting back on the topic. What I find interesting is that, while I'm sure they could tune a car or motorcycle to run even better without the converters, the modern sports car or sportsbike is definatly not suffering much by having a converter on it. Todays Mustangs and Camaro's and or Yamaha R1's, ZX-10's, etc, etc, put out a tremendous amount of HP, still get pretty good fuel mileage (considering) and are reliable. They have started putting smog devices on Semi trucks since 03, with another round in 07 and in 10 and they have really affected the reliability and maintenance of the semi trucks. The trucking industry is going though the same phase the cars did in the mid to late 70's.

[lego1970]

My buddy Jimmy and I were between calls doing some top speed testing... :roll:

That statement cracks me up because I know you're not just saying that......I know you actually went out and topped out an ambulance. The visual is hilarious.

I agree with doing that. I think any self-respecting EMS or Doctor should know the top speed of an ambulance. How can you accurately do your job without such information 8)

[SpudRider]

I might be wrong but I think pretty much all street legal bikes run cats now. BMW, IIRC, started it in the 80's with the K bikes.
Neither my 2006 Zong, nor my 2005 XR650L had catalytic converters, Doc. ;)

Spud :)

[FastDoc]

My buddy Jimmy and I were between calls doing some top speed testing... :roll:

That statement cracks me up because I know you're not just saying that......I know you actually went out and topped out an ambulance. The visual is hilarious.

I agree with doing that. I think any self-respecting EMS or Doctor should know the top speed of an ambulance. How can you accurately do your job without such information 8)

They would do what we called M-speed.

This was in the days of 85 MPH speedos and at the bottom would be the letters M P H. We could get the needle past the '85' and get it to point to the M. Unstable over 80 though, and don't even try it unless ther is no wind. :D

[katoranger]

I performed a top speed test on the ranger today. 78mph. :lol:

[Weldangrind]

My buddy Jimmy and I were between calls doing some top speed testing... :roll:

I appreciated that image as well. :lol: Is that the same buddy that rides your buddy bike once a year?

[Weldangrind]

Sorry for hijacking your thread Weld.

Totally cool with me. :D Even though I'm sure that management would prefer to keep threads on topic, I consider my threads to be somewhat of a jumping point. Besides, you reeled it back in. :lol:

BTW, I can totally appreciate your "that makes sense" moments. They are happening to me with increasing frequency.