Delete Cat question

[dyeager535]

Magnaflows 1990 K5 replacement converter appears to be heat shielded, probably not likely to start fires that way.

Im no longer a dual exhaust fan anyway, but even barring my distaste, I suppose running twice as many cats also means twice the possibility of starting fires. Just saying.

I suspect running duals with converters could make the cats not as effective. They need to reach proper temp to work right. Design of the converter and location in the exhaust would need to be taken into account to make sure they are doing what they are supposed to. Not getting too hot, nor staying too cool.

It's illegal to subtract OR add to the number of converters a vehicle came with. Since dual exhaust was essentially killed by converters for awhile, it makes sense that people were inclined to add a converter when going dual, thinking they were complying with the law. Yet still unintentionally defeating the actual emissions reductions the OEM cat achieved.

 

[scouthead]

Around my parts... "delete cat questions"... are more like:


"who the hell crawled under my truck and did a cat delete last night?????"

 

[Bent77]

Yea, so far you're the "winner" in that contest

 

[BlueBurb82]

To answer the cat starting fires question, it doesn't happen as much as it used to but still possible on these older vehicles. The converter is just that, it takes unburned hydrocarbon and converts it to co2 and water. They use precious metals like platinum, palladium and rhodium (which is why they are worth money to scrappers and often stolen) to convert via chemical reaction. Said chemical reaction creates heat. Excess fuel in the exhaust causes them to overheat and as mentioned, can heat the unit cherry red. I saw this a lot in my mechanic days. Checking converter temperatures was actually used in diagnostics. A single cylinder not firing is enough to cause them to overheat.

It isn't as common as it used to be because modern vehicles will throw codes immediately on detecting even a slight misfire. Some will even go into a limp mode, limiting power/throttle, allowing you to only "limp" home. This is to protect the engine/cat when these conditions are detected. OBD also changed a lot. The oxygen sensors detect excess fuel and will begin to reduce injector on time for efficiency. Reduce too much and will throw a check engine light on with a rich code signaling an issue before it damages the cat.

Hope this helps answer any questions.

 

[pparker]

To answer the cat starting fires question, it doesn't happen as much as it used to but still.

Thank you for this. Yes that is a great explanation and makes perfect sense.

I was thinking of getting afr gauge just to make sure i have a good tune on carb, this is another good reason to get that gauge.