Horns, Mirrors, etc.

Air Horns

Also see Air Horn Installation

Many Miata owners who are tired of getting "lost" in traffic due to the slightly smaller size of their car have found a creative way to command a little more respect on the road. They've installed Air Horns. The stock Miata's "meep, meep" is replaced by a high decibel blast that is pretty much guaranteed to get some attention.

The concept behind all air horns is the same. A compressor is wired to the horn switch, generally through a relay. The compressor is a small cylinder with an air output port. Plastic tubing is then run from the compressor port through a "Y" splitter and then to two trumpets. Although its possible to find air horns containing one or three trumpets, a two trumpet setup is the most common. When the horn is activated, the compressor generates a blast of air to the trumpets causing the ear splitting dual tone blast that is pretty much guaranteed to piss off your neighbors.

The different compressors draw different current loads. In many cases, the compressor can be attached directly to the existing Miata wiring. The horn from Crazy Red Italian supposedly falls into this category. Other compressors, such as the Wolo, draw just a bit too much current. In the case of the Wolo, when the horn is activated and the brakes are applied (illuminating the brake lights), the total current will overload the fuse and cause it to blow. You will then lose both your horn and your brake lights. Clearly an unacceptable situation. This problem is rectified by installing a relay in the horn circuit. (All of the air horns come with a relay in their kit.) The existing horn wiring is connected to the relay and the relay then switches current directly from the fuse box to the horn compressor.

One downside (although minimal) to airhorns: Since they're air powered, there is a very slight delay between hitting the switch and scaring the pants off of the guy in front of you. Granted its less than 1 second, but their is a slight delay. I've found that when wiring through a proper relay with the compressor power coming from a suitable source, the delay is less than if you wire directly into the existing horn wire.

We've had one report of air horns "clogging". However with all of the positive feedback we've received, its possible this was an isolated incident due to the installation or the environment in which it was used.

Connecting the Relay

Most of the horn kits are supplied with relays having terminals marked with numbers 85, 86, and 87. If yours does not, these instructions do not apply. Consult the installation instructions supplied with the horn kit.

  1. Connect the existing horn wire to the new horn relay terminal 86.
  2. Connect the air horn compressor + terminal to the horn relay terminal 87.
  3. Connect the air horn compressor - terminal to ground.
  4. Connect horn relay terminal 85 to ground.

There are several companies that manufacture air horns. Some of the more popular ones are:

Of these, the most popular with Miata owners is the kit built by Crazy Red Italian, a company owned by David DeNuzzo. David has selected an appropriate compressor/trumpet combination and added a special bracket setup which simplifies the installation in the somewhat cramped Miata mouth. David also includes instructions which are said to be quite good.

More on air horns

By Rob Meldrum

Maybe the subject on this should have been "Moron Air Horns."  Having  followed the air horns thread for over six months, I thought I'd share my  experience.  If you are in a rush and don't like learning from other  people's errors, delete now...

In my younger days I had an MG Midget, and my best addition to it was a  set of air horns.  I loved popping those bad boys and seeing offending   truckers look around for the source.  So I knew I wanted to give The   Lobster a better voice.

I was out getting an antenna for my wife's car, saw some really cool   FIAMM air horns at Nationwise and the helpful guy there sold me on them  (he uses them himself).  Having no clue what power they draw, I followed  Drake Daum's advice and bought an in-line fuse to power them directly  from the fuse block.   By the way, living in Cincinnati I have had the   pleasure of seeing Drake's tricked-out Miata, and as I accumulate MSU's  (Miata Spending Units), I struggle to replicate his best achievements.

I'll admit one critical fact right now.  I'm OK on the theory end of  things, but I'm a mechanical klutz, which made the thirty-minute   installation procedure an afternoon's effort.  If my writing seems a    little discombobulated it's because of the numerous Homer Simpson   headslaps I administered to myself (DOH!)

First off, back in March, Pete (Meoughta@aol.com) sent in a great   write-up on locating spots to mount Hella air horns, compressor, relay,  and how to wire everything.  Get it from the archives, it's worth the  download.

I removed the plastic cover over the radiator, no problem.   Removed the  old horn (to the left of the hood latch), with a 10mm socket wrench.   Found the hole to the right of the hood latch, the larger air horn fit   just right, so then I had to spend fifteen minutes in the basement  scrounging up a discarded L-shaped angle iron, then had to bore out the  holes with a drill bit so the bolts would fit, mounted it just so, and  then realized that the air horn tubing mounted on the BOTTOM of the horn  mount, and was unreachable once the horn was mounted.  DOH! 

So I unmounted the first horn, cut the tubing into two identical short  lengths to reach both horns, with the remainder to go from the tubing Y   connector back to the compressor, and then hooked up the tubing to the  horn.   Remounted horn number one. One hour dead and gone, but hey, I've  got the job half done, right?

Horn number two was a tighter squeeze, just need another angle bracket,  which I DON"T HAVE!  I did find an old large hinge, cut off a section of  that, and bent it to make a fine custom piece of metalwork to hang horn   number two.  Yes, drilled it out, then found that I'd cut the tubing   lengths just right for final locations, but not enough slack for   preconnecting.  DOH!  However, with some knuckle-scraping and a few   unkind words, I managed to get it connected and mounted.  Another hour   donated to the love of my Miata.

Now to the relay.  Hey, FIAMM used a different numbering scheme than  Hella, so I'm on my own here.  One on one, mano a mano with the   instruction sheet which (conveniently enough) is written in German,  French, Italian, Japanese, and English by (I'm guessing here) a Norwegian  electrical engineer.  The most interesting thing about the installation  was the identification of four wiring posts on the relay in the  instructions, but FIVE posts on the relay itself!  Two of them shared the  same number, so I did the wise thing and wired it up blindfolded.   Actually, I just assumed that one number 87 post was as good as the  other, and winged it.

Before final mounting, I thought I'd test the setup to see if my   assumption worked.  YES!  Unfortunately, sounding air horns in an   enclosed garage emphasizes the extreme volume of the new horns.  DOH!

All righty, then, mount the compressor to the left of the hood latch in  that nice big hole.  Just maneuver that nut over the washer and onto the   bolt, wiggle to get it seated, gently now...DOH!  The nut slipped out of   my hand, and disappeared into the nether reaches behind the radiator.    Didn't hear it land, couldn't find it in the plastic drain pan. 

Removed compressor and relay, put down hood.  Drove the car back and  forth in the driveway.  Nothing.  It's gone.  Off to ACE hardware to get  another bolt.  It's 10mm and 1.00 pitch I found out after lots of trail  and error.  Back home, I reopened the hood.

Compressor mounted just fine, thank you.  Hooked up all the wires using  old spade lug connectors left over from another project.  Looking very
good now, using black wire for ground connections, red for power.  OK!

Wow, this relay is a tight squeeze, next to the compressor, hooking onto  the old horn bolt location.  If I twist this thing and push it over --    Sizzle, sizzle, electrical noises -- DOH!  I managed to push the HOT   spade lug against the car metal.  Don't have the battery wire connected,   you numbskull! 

Got the relay mounted, ran wire to the in-line fuse (thanks again,   Drake), and to the unused connector for ABS (don't have that).  Used   bright yellow wire ties to make everything neat and tidy.

Struggled to get the plastic cover over the radiator, and then the hood  wouldn't shut.  I had put the cover over the latch that allows the hood   to shut and open.  DOH!  Fixed that, and everything works great.

Lessons:  1)  FIAMM  kit comes without wires, spade lug connectors, good  instructions, or mounting brackets and hardware.  I am sure the Crazy Red  Italian whups it but good in the ease of installation category.

2)  Everything feels good and solid, built to last.   Haven't seen the  other air horns, but I like the quality of FIAMM.

3)  If you do a lot of car work, you probably have everything you need,  and this is indeed a half-hour job.  If you have one small tool box and a  cardboard box of miscellaneous screws, bolts and nails, budget a couple   of trips to the hardware store.

4)  Even frustrating incompetently-performed work on a Miata is fun, and  makes the car a little more special to you.  The Lobster is now looking  forward to an opportunity to SHOUT at some highway ne'er-do-wells.

Four hours spent, and I only caught the last ten minutes of Ohio State  putting the hurt on Notre Dame.  Still and all, a project worth doing.  

The FIAMM's have a nice high-pitched two-tone sound (pleasant root and  third of a major chord: A Major?  Have to check that out).  And I did   figure out what FIAMM stands for.  Fix It Again, Miata Man.

Hope you laughed while you read this...

Rob Meldrum and '94 B, with MSSS, Red

Thinking, "Come on, you Cadillac, drift over a little more so I can blast  you!"


What can be improved on a mirror? Either you can see behind you or you can't, right?

Well, not quite. There has been a major improvement to the stock rearview mirror from the Miata Aftermarket - the addition of interior lighting. Those little stock lights that illuminate the footwells are great if you need to check to see if you stepped in doggy poop, but don't really cut it as far as helping you see the ignition switch or to read a map in the dark.

There are a couple of lighted mirrors on the aftermarket. The principle behind them are the same: they get wired into those little footwell lights so the lights under the mirror come on when the door is opened. The difference is in the mounting.

The best mounting method for the lighted mirror is the existing permanent mount along the windshield header. The Mighty Products mirror uses this type of mount. There may be one or more other lighted mirrors that have come out in the past year which also use this mount, but I've installed the Mighty Products mirror in my own car so I'm positive about that one. The other type of mount is glued to the windshield. Although I've never actually seen one of this type, other Miata enthusiasts have mentioned that they didn't especially like it.

Installation is straightforward. The kits include wiring and well written instructions. The wiring from the mirror is concealed under the plastic trim along the windshield header and down the windshield pillar. It then runs under the dash (behind the glovebox) and into the back of the passenger's side courtesy light with included connectors. The entire job requires no special tools and can be done by almost anyone in under an hour.

Both types of mirrors are available from several aftermarket sources.

Back to The Garage

14 March, 1999

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Copyright 1999: Eunos Communications LLC