Catalytic Converter - which parts to protect?

2006 Prius.

Can somebody who knows the Prius exhaust system confirm which are the valuable CAT parts? Starting from the manifold flange, there is the first can that I assume is a CAT. Then the O2 sensor installed in a bent section of connecting pipe, then another can, a straight pipe, and then a big resonator and the rest of the exhaust system that that thieves don't care about. Are both of these front cans with the O2 sensor between them (and heat shield above them both)... are they both CATs? Thieves seem to take them both. But would they take just the front one if it were too difficult to also take the back one? Or is the front one perhaps the only thing with Platinum in it, and they cut the pipe in the back for convenience? (Turns out that my guess was pretty accurate).

Mine was cut at that straight pipe section as shown in the first image below, so that the two front cans were taken as a set. Now that I have a replacement installed, I have reinforced that area... but not the pipe between the cans where the O2 sensor is (since rectified, see lower in the thread!). Should I protect that as well? (Doesn't matter... I did)

My protection consists of a hardened steel bar that I welded across that thin-wall pipe, plus a chain welded to the body of the car.

 

Hey Danny! Been a long time.

Several things:
1. I'm in the Sacramento area.
2. I immediately filed a police report. 12th theft in this exact (college) lot in 2019.
3. I live in the town of Davis, and we've had 40 reported thefts in 2019.
4. It is a HUGE problem here. They have now run out of the part. I got the last one in the area.

 

The other telling sign about the front one being the "important" one is that the O2 sensor is behind it, and there isn't another sensor behind the second one. As far as I know, the thieves alway take them both. But to be sure, I have now reinforced the thing-wall connecting pipe between the two cans where the sensor is.

 

I spend a lot of my time thinking like a thief and studying their ways. In fact the product you see welded up to my exhaust system is all recovered stolen property. Think of me as a trained thief who's been blessed by my local PD. . I'm working directly with the police on this (all PDs in the area are now coordinating because they have to get a handle on this. I have already agreed to press charges if they catch somebody). Anyway, I've learned many things through the years. And one of those things is that there is often a most common way that things are stolen, but there is no single way. And note that this happened at 3pm on a beautiful, bright sunny day in an open parking lot.

In every video I've seen of this theft, somebody first looks under to make sure it is worth committing to jacking the car. At some point they absolutely need to see what they're doing. You aren't going to hit those flange nuts with a socket on the end of a 24" extender unless you're looking. And you can't appropriate position a saw or cutter without looking. And what I've done makes the socket not work, and the chain cutter not work. They can't even get started. They *could* get started with a saw.

And the bottom line: Even if they cut through the pipe and my hardened bolt and my chain (if they didn't first consider where best to cut... note that the chain placement isn't random) They still can't get the flange nuts off. I can weld the cut back up in a jiffy. Way better than losing the whole thing again, even if they do managed to get a cut started.

 

I've just spoken at length with my local exhaust shop CAT guy who did my replacement. This guy is BUSY. Literally my Prius was just one of six that he replaced CATs on this week alone. Unreal. Anyway, he explained the various cans to me (answering my original question of the thread!)

The first can after the flange is THE valuable one. The second can he calls "part resonator, part cleanup." The second one doesn't have any value to recycle. But he says of the 30 he's recently seen BOTH cans are always taken because it is the easy place to cut.

But knowing that the front one is the valuable one, I decided to climb back under there and put a second bar between the two cans. So you can see what I did near the O2 sensor below. I also added springs to my fancy chain... because it rattled and sounded like popcorn under there! Now I'm done. I'm somewhat confident that nobody is gonna walk off with this thing any time soon.

 

In CA you don't have much choice: You need to use an OEM unit. There are some online places that sell them for cheaper. And if you're handy, you can install them just fine. There's no way that I could find a better deal than my $100 deductable to have the whole thing replaced. And then of course I did all of the "protection" myself. The muffler shop wouldn't weld for fear of wrecking the Prius "electronics." Maybe I was lucky.... no problems here.

 

That's awesome! Those who don't think like thieves do will consider: Well, that's easy to remove. Just get a driver to remove the clamps and remove each cable... or just cut them!

Doesn't work like that. They know the exact tools needed to remove an OEM product. And that's what they bring with them and know how to use efficiently and quietly. They don't have an entire tool box... nor do they want to spend the time devising a way to defeat some unique thing. Sure the cables can be cut easily.... if you have the right tool with you. But they don't.

Nothing is completely secure. But they sure as heck aren't going to spend time unraveling that!

 

Yeah, I don't have a lot of coverage on the Prius. But my insurance won't let me have different comprehensive on the two vehicles, and I sure wanted coverage on the new Tesla. So as luck would have it, this has now paid for any premium I'm paying on the Prius for many years to come.

Odd definition of "luck" but whatever! These parts are expensive. And if you have to pass smog (as in Calif.) then you'll need to have a genuine product on the car that still does its job.

My new one is also stamped with my VIN. I think I've done all that I can reasonably do to prevent this from ever happening again.

 

There's a vanishingly small market for used CATs. The buyers of the scrap is where we're seriously looking. The CATs can't legally be recycled unless the numbers all match (I'm only speaking for Calif here, don't know about the rest of the country). We can't yet figure out who is paying for this stuff. This won't be solved until we stop the market for the stolen product.

 

I appreciate your confidence in me, but the chance of screwing up the car in some way is too much liability for me. My local muffler shop will not weld with the parts on the car as I have done. They claim that they've seen the Prius computer screwed up by doing this. I'm skeptical about that, but as I've gotten older, I've become more conservative in what I'm willing to do on other cars. Sorry about that.