Best catalytic converter anti-theft device, Gen 2?

srellim234 · Apr 12, 2023

Beige Bruiser said: ↑

Our 2007 Prius, which we've owned since it was new, had its catalytic converter cut out last night, despite being parked right under my bedroom window--the thieves must have worked incredibly quickly & quietly. Fortunatly, we have comprehensive auto insurance with no deductible, which will help defray the high cost of having it replaced by our local dealer. Currently with 165,000 miles, we intend to keep our Prius to 300,000--it is by far the best car we have ever owned. We will need to protect the new cat from being stolen again.
If any of you have experience with any of the aftermarket anti-theft devices designed for this car, please let me & others benefit from it.
Some of the devices that came up in an initial search of past posts on Priuschat are as follows:
1) Catclamp -- it looks like it would not trap heat, but does it rattle or have other disadvantages?
2) Miller Cat Shield, some reports indicate problems with rattling, and would it cause overheating?
3) Cat Security, -- it sounds like it could not be removed once installed, and are there problems with rattling or overheating?
Thank you in advance for any advice you can share. As a longtime Priuschat member, we have gotten invaluable advice here in the past.
Bill in Ypsilanti MI

Hi Bill,

I have had 4 cats stolen from my '07 Prius. The first two with "the shield". It was easy for the thieves to remove and they just left it under the car, undamaged. The second shield was bolted with several different kinds of hardware. The next $550 anti-theft device I bought was called "the cage" and made with metal that supposedly turned into razor blade sharp when one cut it. After 8 months of peace, the thieves cut it.

I think the shield is useless and "the cage" is better. Perhaps in a less "hot" area the cage would last longer.

My driveway mechanic who I went to after the expensive installs failed me makes something custom with insanely thick metal that he welds on. I'll try that next.

I bought a cheap after market cat on eBay because I'm so fed upland stuck signs on my '07 Prius that my cat is worthless.

Good luck!

It's a headache.

Vanessa
Click to expand...

We had the top of the line Miller Cat Shield installed on our Prius and wound up taking it off. Our mechanic spent over a week trying everything he could think of to get it to stop rattling before he even allowed us to take it home. We finally couldn't take the rattling anymore so now the shield just sits propped up against the wall of the garage, waiting for us to either figure out something to do with it or donate it to one of the local thrift shops and make it someone else's headache. Nice idea but a total waste of money.

bnprius · Apr 12, 2023

Vanessa,

Thanks for your comment on my post from November 2021. Back then I decided to go with MillerCAT. It did seem to solve the theft problem, since my new OEM cat has not been stolen again. This, despite frequent ongoing reports of cat thefts in our area (Ann Arbor-Ypsilanti MI).

However, the original MillerCAT rattled against the engine, despite the Toyota dealer having installed it carefully following MillerCAT's instructions. The dealer was able to bend out the shield's louvers, which seemed to cure the problem, until it started up again. That time, the dealer made a video showing that it "popped" up & down. When I sent this video to MillerCAT, they offered to replace the shield with a completely redesigned one, for free. Of course, the costs for taking off the old one and installing the new were covered by me.

The redesigned MillerCAT is a huge improvment over their original design. It has never rattled, not once.

Bill in Michigan

bnprius · Apr 12, 2023

srellim234 said: ↑

We had the top of the line Miller Cat Shield installed on our Prius and wound up taking it off. Our mechanic spent over a week trying everything he could think of to get it to stop rattling before he even allowed us to take it home. We finally couldn't take the rattling anymore so now the shield just sits propped up against the wall of the garage, waiting for us to either figure out something to do with it or donate it to one of the local thrift shops and make it someone else's headache. Nice idea but a total waste of money.
Click to expand...

Srellim234, here's a quote from my reply to Vanessa:

After our cat was stolen from our Prius in 2021, I had our Toyota dealer install the best MillerCAT stainless steel shield for the Gen 2 Prius.

However, the original MillerCAT rattled against the engine, despite the Toyota dealer having installed it carefully following MillerCAT's instructions. The dealer was able to bend out the shield's louvers, which seemed to cure the problem, until it started up again. That time, the dealer made a video showing that it "popped" up & down. When I sent this video to MillerCAT, they offered to replace the shield with a completely redesigned one, for free. Of course, the costs for taking off the old one and installing the new were covered by me.

The redesigned MillerCAT is a huge improvment over their original design. It has never rattled, not once.

I recommend that you call MillerCAT and ask them to send you the completely redesigned shield--for FREE. You can tell them that they did this for me, Bill Nolting in Ypsilanti MI.

Georgina Rudkus · Apr 12, 2023

Any kid in high school shop learns that a flat sheet of metal will flop around like a flag in the win.

Adding longitudinal folds or crowning the sheet like they do with body panels on cars gives the sheet metal structure and rigidity.

Simply bending three longitudinal radial flows with the lowest part under the exhaust pipe of cat totally eliminates contact from vibration as the car is driven.

I did this with the flat cat shield that I put on my Prius v. The same can easily be done with ant Gen 2 cat shield.

Best catalytic converter anti-theft device, Gen 2?

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Best catalytic converter anti-theft device, Gen 2?

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