1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Catalytic converter protection: Auto Defender vs. Cat Shield?

Discussion in 'Gen 3 Prius Accessories and Modifications' started by NewHybridOwner, May 17, 2020.

  1. NewHybridOwner

    NewHybridOwner Active Member

    Joined:
    Nov 21, 2018
    607
    278
    0
    Location:
    W. Michigan
    Vehicle:
    2015 Prius
    Model:
    Four
    I have already seen posts here concerning the Miller Cat Shield, but now I see that there is a competing product called Auto Defender, which is very similar in shape but claims to be held in place by more fasteners and also comes with a second part that covers a different part of the exhaust system..
    I have no idea who copied which. Has anyone used either of these, and why did you choose that one?
     
  2. Raytheeagle

    Raytheeagle Senior Member

    Joined:
    Jul 1, 2016
    11,251
    15,474
    0
    Location:
    Bay Area, California
    Vehicle:
    2019 Prius Prime
    Model:
    Prime Plus
    I bought one from Cap City Muffler out of Sacramento for our 2019 Prime:):

    1A222F6C-A10A-46DD-A8EE-18C1164A6BB7.jpeg

    Not installed yet, but will be once the lockdown ends;).

    Seems like it'll deter just fine and the sticky finger thieves move along to the next mark(y).
     
    TGrracie, PrimerPrius and RMB like this.
  3. NewHybridOwner

    NewHybridOwner Active Member

    Joined:
    Nov 21, 2018
    607
    278
    0
    Location:
    W. Michigan
    Vehicle:
    2015 Prius
    Model:
    Four
    Looks similar to the Auto Defender ones. But are those fasteners simply rivets that would have to be drilled out to get at the catalytic converter if it became necessary? The Cat Shield uses rivnuts/nutserts with security Torx screws.
     
  4. Raytheeagle

    Raytheeagle Senior Member

    Joined:
    Jul 1, 2016
    11,251
    15,474
    0
    Location:
    Bay Area, California
    Vehicle:
    2019 Prius Prime
    Model:
    Prime Plus
    Some are rivets;).

    But if the thief wants the cat bad enough, nothing will stop them:cool:.

    I'm doing this to deter and when I have to park out in public, the thief will move along as it's not a 2 minute job:whistle:.

    Effort required and making it less easy is good enough for me(y).
     
    Montgomery likes this.
  5. PrimerPrius

    PrimerPrius Junior Member

    Joined:
    Jun 1, 2019
    13
    18
    0
    Location:
    Santa monica
    Vehicle:
    2019 Prius Prime
    Model:
    Prime Plus

    I just purchased this today and looking forward to get it installed on my 2019 prime as well.
     
    TGrracie and Raytheeagle like this.
  6. Raytheeagle

    Raytheeagle Senior Member

    Joined:
    Jul 1, 2016
    11,251
    15,474
    0
    Location:
    Bay Area, California
    Vehicle:
    2019 Prius Prime
    Model:
    Prime Plus
    Pics when done;).

    I'll do the same(y).
     
    PrimerPrius likes this.
  7. AtotheZ

    AtotheZ New Member

    Joined:
    Jun 4, 2020
    1
    5
    0
    Location:
    Santa Cruz, CA
    Vehicle:
    2011 Prius
    Model:
    II
    +1 for the CapCity muffler Cat Shield. They shipped it same day (last week) and although I am not a car guy, my friends helped me install it. Took them less than 45 minutes. It uses rivets as a deterrent. They said they added a couple of screws (With varying head sizes/types) to ensure it wasn’t going to rattle, as by design the part is made from aluminum (light weight and has a tendency to “gum up” a saw that might be used to go after a cat converter. You do need to have a rivet gun for installation but it seemed very straightforward once they got the car up on jack stands.

    when I read that thieves nailed 5 Priuses in ONE night just a mile or two from my house, ordering this was a no brainer. $200 vs $2000+ for a replacement car converter?
     
    Barsoapguy, m2b, RMB and 2 others like this.
  8. PrimerPrius

    PrimerPrius Junior Member

    Joined:
    Jun 1, 2019
    13
    18
    0
    Location:
    Santa monica
    Vehicle:
    2019 Prius Prime
    Model:
    Prime Plus
    I completely forgot to take pictures when the car was up on the lift but this is the best I can do for now . I got it installed for $40 near Bellflower.
    The process took a little under 30 minutes and I’m very satisfied with the result.

    35297711-9E36-441E-994E-4E69B899F153.jpeg A2DC57BB-5943-47F9-A21D-043670D33F23.jpeg 1638EF41-445E-45A1-BC47-BF9F76F0D9F9.jpeg
     
  9. Raytheeagle

    Raytheeagle Senior Member

    Joined:
    Jul 1, 2016
    11,251
    15,474
    0
    Location:
    Bay Area, California
    Vehicle:
    2019 Prius Prime
    Model:
    Prime Plus
    Looks great ;).

    Mine should look similar soon(y).
     
    PrimerPrius likes this.
  10. PrimerPrius

    PrimerPrius Junior Member

    Joined:
    Jun 1, 2019
    13
    18
    0
    Location:
    Santa monica
    Vehicle:
    2019 Prius Prime
    Model:
    Prime Plus
    Awesome! do remember to take pics and post :)
     
    Raytheeagle likes this.
  11. Raytheeagle

    Raytheeagle Senior Member

    Joined:
    Jul 1, 2016
    11,251
    15,474
    0
    Location:
    Bay Area, California
    Vehicle:
    2019 Prius Prime
    Model:
    Prime Plus
    No worries with that ;).

    When @The Critic and I get together, we share the results:):

    What did you do to your Prime today?

    He has a lift, so it makes work like this a breeze(y).
     
    PrimerPrius likes this.
  12. Raytheeagle

    Raytheeagle Senior Member

    Joined:
    Jul 1, 2016
    11,251
    15,474
    0
    Location:
    Bay Area, California
    Vehicle:
    2019 Prius Prime
    Model:
    Prime Plus
    I guess one question I forgot to ask: do you know if they had to modify any of the mounting points, or were the connections in the ore drilled locations:whistle:?

    Just checking to see if they mentioned anything before I get too far into it;).

    Thanks for the assist if they shared (y).
     
  13. Dan Youngers

    Dan Youngers Junior Member

    Joined:
    Jul 18, 2009
    2
    0
    0
    Location:
    California
    Vehicle:
    2007 Prius
    Model:
    N/A
    I recently had my catalytic converter stolen on my 2007 Prius. I will perform the repairs myself using the genuine Toyota Catalytic Converter for California per CARB. I'm concerned that by adding a Cat Shield to the underside of my car this will not allow the heat to dissipate away from my Catalytic Converter, thus shortening the life. Should I be concerned, has someone measured the heat differences between stock open underside and covered with a Cat Shield or similar device?
     
  14. Attila Fekete

    Attila Fekete Member

    Joined:
    Apr 5, 2019
    164
    58
    0
    Location:
    Budapest, Hungary
    Vehicle:
    2012 Prius
    Model:
    II
    Does the catalysator need cooling at all?
    My understanding is that it need to be kept hot to make it work.
     
  15. ice9

    ice9 Active Member

    Joined:
    May 3, 2019
    581
    343
    1
    Location:
    norfolk va
    Vehicle:
    2018 Prius
    Model:
    Four
    Looks like all you need is a crowbar to remove it.
     
  16. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,467
    38,102
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    A crowbar and maybe an extra 20 minutes, under a car precariously supported by just a jack.
     
    Barsoapguy, ice9 and Raytheeagle like this.
  17. ice9

    ice9 Active Member

    Joined:
    May 3, 2019
    581
    343
    1
    Location:
    norfolk va
    Vehicle:
    2018 Prius
    Model:
    Four
    With an aluminum panel? I wouldn't think it take that long... ...but yes, with the car perched on jack? That would be dicey. Good point.

    A crow bar, jack and jack stand might get the job done, but you still need the reciprocating saw - all of which would require a fair amount of planning and coordination. Hence Ray's comment...

    ...so the kit would be effective against your typical parking lot thief who probably wouldn't be prepared to tackle such a job.

    I'm almost sold on this idea. The only question I have now is regarding heat. Will covering the cat and restricting air flow reduce life expectancy?
     
    #17 ice9, Jun 21, 2020
    Last edited: Jun 21, 2020
    Mendel Leisk likes this.
  18. NewHybridOwner

    NewHybridOwner Active Member

    Joined:
    Nov 21, 2018
    607
    278
    0
    Location:
    W. Michigan
    Vehicle:
    2015 Prius
    Model:
    Four
    Th Miller CatShield people claim that their design -- with louvers rather than just slots to allow the number to be read -- actually keeps the cat converter cooler.
     
    GrayRaceCat likes this.
  19. Georgina Rudkus

    Georgina Rudkus Senior Member

    Joined:
    Sep 15, 2018
    3,096
    2,163
    0
    Location:
    Taylors, SC
    Vehicle:
    2012 Prius v wagon
    Model:
    Two
    cat defender packaged.JPG The Gen 3 Auto Defender that I ordered on Thursday, arrived today.

    It is an exact clone of the CCM excepting the logo cutouts and the vents,

    The mounting screws and rivets are the same, as the location of the holes.

    I had to cut out a 3 inch 3/4 inch strip off the rear, since the cooler behind the catalytic converter on the Prius v is wider there. Uncut, the edge of the plate hits the cooler.

    Instead of using the rivets an one way screws, I considered using all stainless steer rivets, but finalized on the Miller Cat method using rivet nuts and stainless steel M6x1.0 security Torx screws.

    I had in my supplies aluminum. steel, and stainless steel rivet nuts. I finally decided on the steel rivet nuts, knowing that stainless steel screws threaded into stainless steel often galls and seizes.

    I have to admit that the Auto Defender is an exceptional quality product at at least $40+ less than the others. Although the Miller Cat can be had in a special Prius v version, it does not include a rear plate. I do doubt how effective the rear plate is. I am still considering whether I will or will not install it.
     
    #19 Georgina Rudkus, Jun 22, 2020
    Last edited: Jun 22, 2020
  20. Georgina Rudkus

    Georgina Rudkus Senior Member

    Joined:
    Sep 15, 2018
    3,096
    2,163
    0
    Location:
    Taylors, SC
    Vehicle:
    2012 Prius v wagon
    Model:
    Two
    What size Torx security screws does the Miller Cat plate use? Are the T27 or T30?

    Thanks in advance.