Temperature of various exhaust parts (choosing paint)

Got in my new Bosal cat-back exhaust. Not installed yet and there's a bit of surface rust already starting where some of the welds are (aluminized before welding, clearly) so I thought I'd see if I could give it a bit more life by cleaning it up and painting the thing before installing it and moving on to the rusting out phase of its life.

It's not a header, and I seriously doubt I need fancy 1200F header paint/ceramic; I'm actually dubious that most of the system ever gets hot enough to even cure that stuff, and I don't have a giant oven. I was thinking I could probably get by with 650F engine paint that far away from the engine. But I only found one post talking about exhaust temperature, and while he was going to take an IR thermometer to his exhaust, he was looking for a cat failure and never posted results/readings, so that was not helpful.

So - anybody that has an IR thermometer want to go out and measure exhaust system surface temps and report what they are at various points along the system? I'm not really interested in what an EGT reads for the folks that have put one of those in the gauge set - just what the outside surface of the exhaust is after a bit of driving. I have a 2.7 dual-cat setup, and if the results happened to be from one like it, so much the better, but any hard data would be better than none.

Something like: before first cat, first cat, between cats, second cat, at second O2 sensor on exhaust pipe, before muffler, muffler itself, tailpipe.

<edit> We'll see how it does, painted with VHT 650F engine paint. $10 wasted or invested on a $126 exhaust....

 

How's the paint holding up? this is something I was wondering about as well. I've done exhaust jobs before and the severe rust really made it a pain in the ass

 

So far so good. A bit dark (or darker than when applied/than the muffler and tailpipe) on the front pipe (between the muffler section to cat flange and the muffler) but not blistering off or anything like that. Muffler and tailpipe look fine. Smelled quite a bit the first few times it was driven, but that's to be expected. I think any further forward (the cats & manifold) you'd actually benefit from the super-high-temp stuff, though getting a proper cure on it seems to be a problem, reading about it (it wants something like bake at 200, bake at 600, which is hard to achieve with running the motor to make parts hot, though I suppose you could certainly try running for 10 seconds, running for 30 seconds, running for a minute, etc.)

For the muffler section, the engine enamel (at least VHT's version) seems to be plenty to take the heat. How much it will help with the rust I won't know until a few years down the road - naturally a lot of exhaust rust happens on the inside, but for $10, even if it adds a year to the muffler it's a win. In the uncured (dried for a week while waiting for sensors, but no heat applied) state it was very easy to scratch, so I did get some scratches on it while installing. Probably should have thrown rags over things but I had reached a point of wanting to get the darned thing in. I may buy another can and paint over those in place.

 

Awesome! thanks for the in-depth review but what about a few pics if you can get decent ones (i know that can be hard on underbody)?