Has anyone tried making/using a catalytic converter warmer?

[roflwaffle]

Originally Posted by theunchosen

You are both arguing slightly different things.

ROFL you are saying that the sheer heat is not likely to get to a temperature high enough to damage the cat for a long period of time. That is true.

Chris is saying that if the cat manages to get hot during the engines warm up status when its flowing very fuel rich the fuel could ignite.

Which would be outside "normal operating parameters" and in the outlier region for a research paper.

Umm... The fuel igniting is how a cat works. That's what oxidation is. It's a totally normal operating parameter.

Originally Posted by theunchosen

That said, cat's catching fire is not unheard of uncommon. It happens. Chris says its happened to him twice. I find that reasonable since my grandfather owns and is one of the main mechanics for a garage and I know this happens sometimes.

What usually happens is for some reason or other the cat gets too hot when the engine is spooling up and dumping fuel. the fuel ignites as it enters the cat(see backpressure= increased heat) and gets obstructed as it tries to expand in the cat. the still rich fuel mixture coming in keeps it going much like a Gas Turbine engine and a "flame holder" (It's actually the exact same thing just the GT does not use any fancy metals on its skin). It would only take a few seconds before that kind of heat would do damage maybe not to the cat directly but surrounding components. . .i.e. the floorboards catching fire or melting nearby components.

Also the enclosed gasoline burn in the enclosed space of the cat would be much greater than its outside burn temperature. definitely enough to burn through floor boards. Seen it.

They're always on fire, well, at least causing them. What you're referring to is when the engine runs really rich for whatever reason and coking leads to an exhaust restriction, which leads to the driver putting their foot down farther to get the same amount of power, which leads to even more unburnt HC in the exhaust stream. Rinse and repeat and the end result is a really hot, maybe melting, coked up cat that'll heat up itself and anything near it.

A condition rich enough to cause this will not happen if a vehicle is operating properly, even if the cat is already warm while the engine is cold. Otoh a carburettor where the float isn't set right, a malfunctioning oxygen sensor, in the case of open loop for OBD-I/earlier running WOT really rich through screwing w/ the AFM/whatever measures the amount of air coming in, no ignition in one or more cylinders, etc... could result in the cat getting too hot and coked up/melted from a constant rich exhaust stream.

[roflwaffle]

Originally Posted by Christ

This also happens over a long period of short heating/cooling cycles, I'm sure.

I mean, seriously.. when I pulled my cat, it was so bad you couldn't see through most of the cells. I actually did a backpressure test through the O2 sensor port, and saw something like 2psi at idle. (Should have been less than .5psi.) This is what told me to pull the cat and visually inspect it.

Granted, that was for a cat nearly 20 years old, and newer ones aren't going to have that damage. But aren't they recommended to be replaced due to heating/cooling cycles damaging them after something like 4 or 5 years?

Your cat shouldn't be that plugged up, even after twenty years, unless it had to deal w/ too rich of a mixture that plugged it up. I have a 26yo truck and a 16yo car in the family, both w/ their original cats passing smog every two years, so they should last for a while if they don't get all coked up due to an overly rich exhaust stream.

That said, having smog every couple years means that I need to keep the emissions within spec, so a condition that results in an excessively rich exhaust stream would have to be fixed or I couldn't register the vehicle.

[theunchosen]

The cat is like an FE afterburner.

When the heat gets high enough to detonate fuel before its actually inside the cat is when it causes the abnormal issues. creates substantially greater pressure in the cat(turbo, high boost) and more intense heat.

If the cat runs too hot the fuel goes off before it gets there. it still does its job of cleaning the air but the cat is not able to pump out any active pressure(like the engine shoveling out hot air) it cannot overcome the expansion of preignited flames and so thats where the pile-up happens.

It's also a somewhat moot point. The cat's going to get warm within probably seconds of the car starting. Yes I know it takes the engine block a long time. . .but the engine doesn't have 400 degree air washing it over it non-stop. What I'm saying is more heat washes out the tailpipe, its smaller and shielded and takes less time to warm up.

Touch your engine block after running it for one minute. Touch your exhaust manifold. Touch your cat. . .catalytic converter. I wouldn't expect your cat to be very warm, maybe fuzzy.

It's why your exhaust air takes a few seconds to get warm, its warming the cat to optimum temperature. I know for certain it doesn't take my exhaust air more then 10-15 seconds to get pretty warm and that much more to go toasty. So saving the cat 30-60 seconds of getting to optimum temperature. . .you're very likely to release many more pollutants from your nearby coal plant that produces your electricity for the heating of the cat. Engine I won't argue because then you gain efficiency and engine efficiency comes above ALL when it comes to regulating emissions.

[dichotomous]

Originally Posted by roflwaffle

Well, CARB exempt for a much larger engine anyway. The only way to find out would be through testing but I'm pretty sure a cat designed for a larger engine will take longer to light off than one designed for a specific engine size. It could be designed for a range of displacements, and in that case it should work o.k. but if it's specifically designed for use w/ a larger engine I have my doubts.

I'm not gonna stick a smaller size cat on my car than the piping its going in. Really, I'm only putting one on there to be legal, if the 12pack and smile version of yearly inspection goes well then I wont be sticking it on at all, you can poo-poo my thoughts on cat's creation polluting more than they clean, but I dont really care, the awsome part is most of these pollutants dont really go all that far, and arent a problem till there is a crazy amount of them in a hot area without rain, I live in a cold rainy area with low traffic, not concerned.

the only problem with the higher flow cat I will be using is that it will only last a few years, instead of the 80,000mi the stock one will, THATS why they are so large, to be a cheep and long lasting as possible. I can assure you it will heat up JUST fine sitting straight after a raceheader that in only a month is now fully blued.... it gets and stays hot, much hotter than the previous. plus there have been others with full racing exhausts and running these cats and gotten tested, and passed, thats why I am going with that exact model, someone with a 2.3l fully built K20 motor pushing 240hp and all KINDS of torque recomended it after finding it and a special muffler actually increased his midrange and low end power without cutting his high end power, and that it tested clean on his (though he has a slightly bigger diameter, mine would only be cleaner).

so basically, I am likely going to be putting something proven clean on my car, even though I dont really care about being clean (the whole summer my non-cat as stock motorcycle is my main ride), and I have DONE my research on it, lay off!

[brucepick]

Yikes. Folks really got into it here. I had a thought on the original topic so here goes...

"Should I build a cat preheater??"

Put a grill block in front of the cat. At least on most FWD cars I've seen the cat is behind the radiator or the a/c condenser. Kill off some of the cooling air flow and it will warm up a lot quicker without a whole lot of re-engineering. I wouldn't kill off all the cooling airflow over the cat, based on discussions here that an overheated cat isn't a good idea.

As for the "Ditch your cat!!" crowd, I'm completely NOT with you. We got rid of a lot of stench and nasty pollution by using cat converters and I don't want that junk back.

I'm old enough to remember country roads and city streets smelling horrible, just from a few cars idling or passing by. Stand near where a few non-cat-converter motorcycles are idling and you'll smell the same thing. Stand near the old car idling before rolling down in a parade, or at a vintage car meet. Disgusting and unhealthful.

I can appreciate guys with PhD's in organic chemistry explaining why it's actually better for the environment to run without a cat converter. For about one hundredth of a second. How many PhD's here on this thread?? Coming from guys with a BS degree, I'll buy the logic for about 1 millionth of a second.

[roflwaffle]

Originally Posted by dichotomous

I'm not gonna stick a smaller size cat on my car than the piping its going in. Really, I'm only putting one on there to be legal, if the 12pack and smile version of yearly inspection goes well then I wont be sticking it on at all, you can poo-poo my thoughts on cat's creation polluting more than they clean, but I dont really care, the awsome part is most of these pollutants dont really go all that far, and arent a problem till there is a crazy amount of them in a hot area without rain, I live in a cold rainy area with low traffic, not concerned.

I'm not poo-pooing your thoughts, just asking for some proof of them. If you have no proof and are just saying stuff because you feel like it, it's no sweat, but don't expect others not to ask you for sources. Hell, if ya don't care, then why even respond in the first place?

Originally Posted by dichotomous

the only problem with the higher flow cat I will be using is that it will only last a few years, instead of the 80,000mi the stock one will, THATS why they are so large, to be a cheep and long lasting as possible. I can assure you it will heat up JUST fine sitting straight after a raceheader that in only a month is now fully blued.... it gets and stays hot, much hotter than the previous.

It's not that it gets hot, all working cats will heat up. The emissions depend on how quickly it gets to operating temperature compare to a functional stock setup.

Originally Posted by dichotomous

so basically, I am likely going to be putting something proven clean on my car, even though I dont really care about being clean (the whole summer my non-cat as stock motorcycle is my main ride), and I have DONE my research on it, lay off!

Proven cleaner by what? I haven't seen any comprehensive emissions testing data for your vehicle, and until you had that I can't see how you could make any reasonable statements about whether or not it actually is cleaner in your case. Granted, you can go w/ the "It's cleaner cuz I said so." line, but that ain't reasonable IMO.

Besides, there's no reason to get your panties in a bunch when someone has a statement about something you're doing. If it's dirtier to run a bigger cat, it's dirtier. If it's cleaner it's cleaner. Like I said before, if you don't care about it *being clean why are you even bothering to post back saying you don't care, just don't post.

*Aside from getting tagged by the CHP and their laser emissions doohickeys.

[Christ]

Originally Posted by roflwaffle

*Aside from getting tagged by the CHP and their laser emissions doohickeys.

It's kinda rediculous that they would use something like that... but I guess I can understand the need for it.

Like I said earlier, I don't endorse removal of the catalytic converter if you can get away with not doing it... in my case, I couldn't afford a replacement, and my car wasn't running properly with it, so as a diagnostic measure, it was required to remove. I don't drive that much since then, due again to lack of money, but if I had the cash, I'd much rather spend it on tuning the car so I didn't need the cat to pass emissions testing.

(I can get away with a look-alike b/c I"m OBD-0.) I'd still like to see exactly what my tail-pipe readings are though... too bad I'm gonna end up junking the car before I get a chance to find out.

[roflwaffle]

From what I've read it's mostly because of the, um... younger element who believe the nonsense about a cat restricting "serious power" on an otherwise stock vehicle or sumsuch.

[Christ]

Originally Posted by roflwaffle

From what I've read it's mostly because of the, um... younger element who believe the nonsense about a cat restricting "serious power" on an otherwise stock vehicle or sumsuch.

Yep. Maybe that's it.

[dichotomous]

Originally Posted by roflwaffle

I'm not poo-pooing your thoughts, just asking for some proof of them. If you have no proof and are just saying stuff because you feel like it, it's no sweat, but don't expect others not to ask you for sources. Hell, if ya don't care, then why even respond in the first place?
It's not that it gets hot, all working cats will heat up. The emissions depend on how quickly it gets to operating temperature compare to a functional stock setup.
Proven cleaner by what? I haven't seen any comprehensive emissions testing data for your vehicle, and until you had that I can't see how you could make any reasonable statements about whether or not it actually is cleaner in your case. Granted, you can go w/ the "It's cleaner cuz I said so." line, but that ain't reasonable IMO.

Besides, there's no reason to get your panties in a bunch when someone has a statement about something you're doing. If it's dirtier to run a bigger cat, it's dirtier. If it's cleaner it's cleaner. Like I said before, if you don't care about it *being clean why are you even bothering to post back saying you don't care, just don't post.

*Aside from getting tagged by the CHP and their laser emissions doohickeys.

never said proven cleaner, said proven clean, as in passed emissions tests in new york. how is someone using a very similar exhaust setup with the same cat having their car pass emissions in the state next to mine (NOT cali) NOT proof of it being clean? I wont name names because I didnt ask permission, but you can go and look around on EPHATCH if you like. the exhaust gasses leaving the vehicle are cleaner than they would be with my old cat with holes, or with no cat as current, is this hard to understand? the high flow cat is a smaller cat, much smaller, so in theory it would heat up quicker because there is physically less to heat up.

I really dont feel like gathering up all kinds of irefutable data to prove my "cats pollute more through their creation than cars would over the life of a cat" theory, especially not to prove it to a forum. logic can work well here, mining and smelting and processing of precious metals is a very dirty process to the environment, it might not make the road you live on smell nasty like a car will, but it will destroy a lot of land and create unlivable conditions for a large area around it. uncatylised cars just shift the pollution to where most of us americans live instead of somewhere else, so we choose the later. if you would like to look into it more then go ahead, I dont feel like pulling together a research paper for you