Burble tune w/cats

[Cubieman]

Running the burble/pop on Martyn's tool and wondering specifically how it will ruin my cats. I have the Euro cats in section 1 if that makes any sort of difference.
I am not running the backfire tune, but the burble/pop. I know it is childish but I do kind of like it. I wondered if it would ruin the cats abilty to clean the exhaust or if it melts the catalyst and just messes the cats/exhaust system up that way. Probably put 100 miles on the car with this tune and plan on removing it before driving again.

[heinzboehmer]

No, it will melt the cats because of increased temperatures in the exhaust track. It might not be as bad with euro cats since they're further downstream, but there's still the exhaust valves to worry about.

[r4dr]

I don't think burble + pop will ruin cats, new cars do it from the factory. Isn't it just leaving injectors on for a very brief interval after lifting off the throttle? Backfiring on the other hand...

[Cubieman]

No, it will melt the cats because of increased temperatures in the exhaust track. It might not be as bad with euro cats since they're further downstream, but there's still the exhaust valves to worry about.

What effect does this have on the exhaust valves?

[heinzboehmer]

I don't think burble + pop will ruin cats, new cars do it from the factory. Isn't it just leaving injectors on for a very brief interval after lifting off the throttle? Backfiring on the other hand...

Is it not the same thing though? You still end up burning fuel in the headers.

[heinzboehmer]

What effect does this have on the exhaust valves?

The burble is due to fuel igniting outside the combustion chamber. This means that the ignition occurs with the exhaust valves open/on the stem side of the valve. As a result, the valves can heat up more than normal and cause problems such as damages to the valve seals. In practice, the damages might turn out to be minimal, but the burble feature is still doing something the engine was not designed to do.

[Cubieman]

I will take component longevity over burble so its going, but I must say the last few long drives with burble I throughly enjoyed!

[Arith2]

We went over this in my drivability class. You are dumping fuel into your cats. It's the same as running rich. Your cats, for emissions reasons, have a chamber to burn any unburnt fuel so hydrocarbons don't get into the atmosphere. Then it crosses through the catalyst that converts the by products to water and CO2. What happens when you run rich, cat temperatures do go up. Also, your cats get clogged. While it probably won't melt the cats, it will clog them quickly, cover your exhaust valves and pistons in carbon too. Burble tunes are just bad for your car. With the explosion happening inside the exhaust, it may also crack your exhaust. The honeycombs inside the cats aren't durable at all so it could break some of those too.

[Albino09]

Speaking from experience as an engineer working in road car engine warranty, burble tunes have a similar effect on catalysts as a misfiring engine will. Long-term, you will melt your cats. My OEM doesn't offer such a tune that we have to deal with, but companies that do offer one are more carefully developed and analyzed for long-term wear and tear than someone's homebrewed tune for an older car. They are legally required to certify a long lifespan on emissions requirements, especially for California and Europe.

[Arith2]

Speaking from experience as an engineer working in road car engine warranty, burble tunes have a similar effect on catalysts as a misfiring engine will. Long-term, you will melt your cats. My OEM doesn't offer such a tune that we have to deal with, but companies that do offer one are more carefully developed and analyzed for long-term wear and tear than someone's homebrewed tune for an older car. They are legally required to certify a long lifespan on emissions requirements, especially for California and Europe.

These reason I don't think the cats would melt is because a misfire would be constantly happening but burble tunes only happen for a short time. I agree it may melt them, but seems less likely since it's not constant. That being said, damage will almost certainly occur.