RX8 Air Horn Upgrade

Thompson-automotive sells an upgraded air horn for Miatas, which can also be installed on the RX-8 (with a few minor changes).

Here's a link to thompson's website:

http://www.thompson-automotive.com/Air_Horn.html

The horn is rated at 139 db. Loud stuff. Here's what it sounds like.

With shipping, it came to about $52.

Here's what you get in the package.

To do the install, you will first have to jack up your car and remove the driver's side front tire.

Once you take it off the wheel, you'll see a plastic cover being held on by plastic screws. Use a screwdriver to turn the screws and then pull them out. There are about 5 inside the wheel well, and a few you'll have to remove from under the car.

Once that's off, you'll be able to see the stock horn:

Here's a closeup. It's being held on by a 13mm nut. Unbolt it, and pull the power cable.

The upgraded horn comes with a few nuts, a metal bracket and some wires (one is ground, the other extends the power connector). The large bolt fits into the horn as shown here:

Then just slide the bracket over it.

It appears that the bolt that holds the horn on the Miata can be reused. We can't do that for the RX-8 since the bolt is part of the OEM horn. Because of this, I can't show you the horn installed on my car since I didn't have a bolt that size handy. Using the included nut, you'd be able to drive to your local automotive store (or home depot) and pick up a matching bolt. You should be able to figure out how it's mounted since there are only a few ways the horn can fit into the car.

The upgraded air horn requires a 20 amp fuse. The OEM horn on the RX-8 uses a 15 amp. So you'll need to replace it. Unfortunately the upgrade kit ships with two fuses, neither are the correct size for the RX-8. You'll want a mini 20 amp connector. Drive to your local auto parts store, pop out the 15 amp fuse and look for one that matches it in size but is listed at 20 amp. They should cost about $2 for a box of 6.

The fuse box is located under your hood in a black plastic box. It is positioned over the driver side wheel, immediately to the right of your intake box. Here's the fuse you'll need to replace:

If you're not sure which fuse based on this photo, the underside of the fuse box lid contains a picture of all fuses and their locations.