Has anyone tried making/using a catalytic converter warmer?

[guudasitgets]

And the hi flow cat that he's talking about is CARB exempt as an aftermarket replacement for *any* vehicle. It's listed as a Hi-flow universal cat. FYI.

Check Magnaflow's website for it, in case I'm wrong.

quit looking for answers in websites, so us YOUR data, something YOU worked on. Show us pics of what YOU did, then maybe we can get some idea of your development and we can learn from it.

[Christ]

K, maybe you missed it when I said I wasn't doing anything myself. I was actually just pointing out (in this case) that the thing that someone was talking about, which someone else decided to dispute, was in fact correct.

Why are you chasing me around trying to jump words on me so much?

[guudasitgets]

Why are you chasing me around trying to jump words on me so much

?


Because,,,,

I wasn't doing anything myself.

[guudasitgets]

now get to work on something, I got a ScanGauge today and learned a lot. Your 23 years old, you can learn too.

[Christ]

Yep. read back a few posts where I said I was out of work and couldn't afford an oil change... maybe you selectively missed that post.

The fact that I have a kid on the way, can't find work in this area, haven't gotten an unemployment check yet, got ripped off about $5000 from one of my old employers, have to go to court every other month for that, and make sure my wife has a way to get to college.

Frankly, I drive as little as possible right now.

[Christ]

Oh. And scangauge = garbage sitting on my dash. Car's OBD-0, bud.

[roflwaffle]

I did, and it said...

If the overheating condition persists for a long period of time, or if the temperature soars high enough, the honeycomb itself may breakdown and melt forming a partial or complete obstruction and causing a sharp rise in backpressure.

Since we're talking about the mixture being slightly richer until the car warms up, maybe ten minutes or so, we aren't talking about an overheating condition that persists for a long period of time. We also aren't talking about really high temperatures unless we have something that's running extremely rich at very high torque/power outputs. For instance, this SAE paper shows via Figure 8 that in order for a cat to reach the damage threshold in terms of temperature it needs a 20% misfire rate, which corresponds to a A:F ratio of under 12:1, at 3000rpm and a fairly heavy load of ~4kg*m=~28ftlb. To put that into perspective a 2L engine from Hyundai when the paper was published makes ~120ftlb at 6000rpm, and ~60ftlbs@3000rpm, so at half load for a 2L engine, 3000 rpm, and a constant less than 12:1 A:F ratio, we can get into an area where the catalyst is at risk. That said, most people don't start up their car and use on average ~30+hp while keeping the engine cold enough to stay w/ the richer A:F mixture constantly. In other words the only way the cat would be at risk is w/ the engine running constantly richer, not just during the warm up.

So in order to see a risk for the cat we would need to run constantly at 12:1 and half of the engine's likely maximum speed and maximum torque. Since an engine run like this is going to warm up very quickly, I doubt we can stay at 12:1 and ~30hp long enough to do any damage to the cat. If we go richer than 12:1 we'll have something that will probably bog down and run poorly, which wouldn't be something a manufacturer would do. Furthermore, higher power outputs require higher speeds and the airflow under the car would help keep the cat cool. I'm betting that short of a constantly rich mixture manufacturers design prevents damage to the cat from being a problem even during WOT cold starts.

[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?

[guudasitgets]

With your wealth of experiance; building over 100+ racing engines; calculating that airplanes landings are really controlled crashes with "minnimal damage", making air compressors out of internal combustion engines and no-all racing Honda engine expert all at 23 years old I'm sure any number of race teams should be calling soon,,,,,,,,,,,,BUD

[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.

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.