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Another Horn Upgrade D.I.Y. Thread - Hella Supertones

Discussion in 'Gen 3 Prius Accessories and Modifications' started by gambit023, May 31, 2012.

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  1. gambit023

    gambit023 Junior Member

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    D.I.Y. Hella Supertones Horn Install on 3rd Gen Prius

    Notes: I did not use the included Hella relay. I read the voltage on the factory horn signal wire and found it to be about 14.4 volts when activated. I’m not sure if the Supertones would be louder if I used the relay to a direct +positive source from the fuse box since they both returned the same voltage. If anyone has more info on this, please let me know. The Supertones are significantly louder than stock so I’m happy with the install even without the relay.

    Before getting started, you’ll need a 1” strip of aluminum to make a custom bracket as the stock Supertones bracket was too short to accommodate the larger horn in the factory location. I got a 1”x4’ strip at Lowe’s for $8. The bracket should be cut to 5.25” in length and mounting holes drilled to 5/16”. The original bracket on the Supertones needs to be removed and replaced with this. Use Loctite when attaching the new bracket as the original bolts holding the brackets on the Supertone were extremely tight. I fabbed up these brackets with a basic hand hack saw and a drill. [​IMG]

    Installation:

    Step 1: Loosen up the front bumper cover (sides and top only). There are two fasteners in each front wheel well as well as several clips and two 10mm bolts on the top part of the bumper cover. I didn’t remove the whole bumper. I just removed the fasteners from the top and front wheel wells and allowed the front bumper to pivot forward giving me sufficient access to do the install.
    [​IMG]

    Step 2: Remove factory horns. I believe each were held on with a 10mm or 12mm bolt.
    [​IMG]

    Step 3: Replace the Hella bracket with the custom 5.25” aluminum bracket if you have not already done so (see first picture). Ensure to use Loctite on the 13mm nut that holds the bracket to the horn. *disclaimer: Hella states warranty will be void if bracket is removed.

    Step 4: Install Supertones in the factory location. The factory horn signal wire fit directly onto the Supertones. I connected the factory wire to the copper colored Supertone connecter.
    [​IMG]
    [​IMG]

    Step 5: Make two ground wires at about 7” in length. Attach a female spade connector on one end and a ring connecter on the other. Connect female spade to Supertone and the ring connecter to the top radiator support bracket. This proved to be a sufficient ground. You can see the two ground wires attached with the yellow ring connectors in the following picture:
    [​IMG]

    Step 6: Test horn.

    Step 7: Reinstall bumper cover. Enjoy.
    [​IMG]
     
    #1 gambit023, May 31, 2012
    sr64olds, Markdizle, Sezy and 4 others like this.
  2. ockevin

    ockevin Active Member

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    Very nice write up.
     
    #2 ockevin, May 31, 2012
  3. xliderider

    xliderider Senior Member

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    Are these horns high/low frequency like the FIAMM upgrade, or are they the same tone? Nice write-up, especially regarding the loosening of the bumper cover, since that particular detail was not covered in the other horn upgrade thread. :)
     
    #3 xliderider, May 31, 2012
  4. wotcher

    wotcher Member

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    classy.
     
    #4 wotcher, May 31, 2012
  5. xliderider

    xliderider Senior Member

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    Hmm, the "edit" link doesn't seem to be working. :(

    I did a search on Amazon, and these horns are offered in a High/Low twin horn kit. Costs about 2x the FIAMM horns though and they are rated at 118db. The FIAMM horns are rated at 130db, but the Hella horns are front facing through the grill and the FIAMM horns point down, so who knows? ;)
     
    #5 xliderider, May 31, 2012
    SlowTurd likes this.
  6. peterjmc

    peterjmc Ping pong in Ding Dang...

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    I love my Hella Supertones :)

    Good job on the write up! My install was pretty much the same. I painted the bracket black with some plasti dip.
     
    #6 peterjmc, Jun 1, 2012
  7. xs650

    xs650 Senior Member

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    Some place on the Interwebs a motorcyclist did comparison sound level test of several horns. Any connection between measured sound levels and manufacturers claims were non-existent. IIRC, you made the right choice.

    Edit: I was actually able to find the test, here's the link
    Motorcycle Horn Comparison Review - webBikeWorld
     
    #7 xs650, Jun 1, 2012
  8. gambit023

    gambit023 Junior Member

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    Thanks for the link. Very interesting.
     
    #8 gambit023, Jun 2, 2012
  9. SoCalBPrius

    SoCalBPrius Active Member

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    Wow, those horns look huge seeing through the grill. Nice writeup btw:).
     
    #9 SoCalBPrius, Jun 3, 2012
  10. sfv41901

    sfv41901 Masta S

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    I like them. Any chance for a sound clip?
     
    #10 sfv41901, Jun 3, 2012
  11. Prius Envy

    Prius Envy F U R Y

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    Thank you and thumbs up for the great write up.
    The only thing I changed was put the ground behind the mounting bracket that was bolted to the body; that way it's a cleaner install.;)
     
    #11 Prius Envy, Feb 2, 2013
  12. xliderider

    xliderider Senior Member

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    Agree, a cleaner install.
     
    #12 xliderider, Feb 2, 2013
  13. xliderider

    xliderider Senior Member

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    This mod could also be included in the Grill Blocking thread as well... it looks to be about a 40% upper grill block. ;) :D
     
    #13 xliderider, Feb 2, 2013
  14. bathala

    bathala Member

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    Thanks for the instructions. I finally finished installing my Supertones. Loosening the front bumper is much easier to replace the horns.
     
    #14 bathala, Jan 26, 2014
  15. Gouda Cheez

    Gouda Cheez Junior Member

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    Thinking about tackling this mod... any reason the relay needs to be installed?
     
    #15 Gouda Cheez, Jan 27, 2014
  16. xliderider

    xliderider Senior Member

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    It all depends on the current draw of these larger horns. If the new horns draw too much current (Amperes), then they could conceivably blow the fuse on the horn circuit.

    Using a relay bypasses the horn circuit as a power supply for the upgraded horns. The original horn circuit is then used only to activate the relay, at a current draw much lower than even the original horns drew.

    SCH-I535
     
    #16 xliderider, Jan 27, 2014
  17. bathala

    bathala Member

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    The initial post is almost 2 years ago. By now someone can tell us their experience of not using the relay.
     
    #17 bathala, Jan 28, 2014
  18. xliderider

    xliderider Senior Member

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    I'm sure someone would've mentioned by now if fuses were blowing.

    SCH-I535
     
    #18 xliderider, Jan 28, 2014
  19. Gouda Cheez

    Gouda Cheez Junior Member

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    You would think so but you never know... :)
     
    #19 Gouda Cheez, Jan 28, 2014
  20. Silvertn350

    Silvertn350 Junior Member

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    Hate to bump an old thread, but I will definitely be doing this. Someone cut me off on the interstate a few days ago and for the first time I hit the horn and was more upset by the sound I heard vs the person that cut me off. Its a problem I have to correct.
     
    #20 Silvertn350, Oct 13, 2015
    sfv41901 and Dylan Doxey like this.
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