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Re: Mounting position of air horns

PostPosted: Wed Nov 19, 2014 1:58 pm
by BabyDriver
It's best not to mount the horns so that the trumpets face forward towards the front grill as water will be forced into them and will corrode the reed over time. Best to face them sideways.

Re: Mounting position of air horns

PostPosted: Thu Nov 07, 2019 2:06 am
by Harvey
I come to this thread about five years late but I want to share the results of my recent installation of a pair of Hella air horns. I had previously installed a pair of Hella supertone horns but i thought they did not offer the vintage Euro sound that my '71 Plus 2S should make when sufficiently aroused. The air horns were about $30 which I thought was reasonable. Air horns were originally fitted to my Plus 2 but one of the previous owners saw fit to replace them.

The goal was to find a place to install the compressor and the trumpets such that they did not interfere with other components in the nose of the car, to fit the trumpets so they were pointed downward to keep water and bugs out of the trumpet reeds, To keep the trumpets as close to the compressor as possible so that the plastic tubing from compressor to trumpets was as short as possible to eliminate any delay in sound once the horn button was pressed, and to point the trumpets toward the nose of the car so the sound would be directed forward.

A bracket had been fitted to the left hand fender which served as a mount for the previous horns. I don't know if the bracket is original to the car or fitted by a previous owner. I decided to use that bracket to hold the compressor. Because the bracket did not allow the compressor to sit parallel to the fender I fashioned a separate bracket out of aluminum flat stock. Next, I made another bracket out of the same stock on which to mount the trumpets and mounted the bracket to one of the body/chassis bolts. I then measured the plastic tubing that came with the kit so that the I could keep the tubing between the compressor and trumpets as short as possible without kinking it and shutting off the flow of air.

From the pictures I have attached, you can see the trumpets situated between the vacuum pod for the headlights and the K&N air filter mounted in the nose. You can also see how the trumpets just clear the left hand radiator fan. Since I have replaced my narrow original radiator with a full width aluminum radiator from Coolex I did not have the ability mount the compressor to the radiator bracket.

Finally, I plugged the power wire coming from the horn relay into the bottom of the compressor and plugged in a short ground wire I made that attaches via ring terminal to the body/chassis bolt that holds the trumpet bracket in place. The sound is just what I was looking for. A vintage Euro (Italian?) high pitched sound that speaks with authority but not in an obnoxious way. I might add that the air horns available now are plastic and not the metal horns originally supplied with the car. I don't know whether this will affect their longevity.

I hope the description and pictures help other Plus 2 owners who want to return to air horns original to the car.

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Re: Mounting position of air horns

PostPosted: Sat Nov 09, 2019 5:11 am
by Sea Ranch
Thanks for the write-up and pix, Lee.

Could you let us know which model, specifically, you installed. Always tough to determine if a horn's sound/tone is suitable by simply reading the advertising on it. :)



ps. My Feb 1970 Plus 2S has the Harry Moss imported "Maserati" air horns installed and I believe they are factory original. The compressor is machined and jewel-like inside, and was painted medium blue hammertone, with some red plastic pieces on it as well. All tubing was red plastic and the horns themselves red plastic. Reed holders are cast aluminum. Not very loud. But cool sound.

Re: Mounting position of air horns

PostPosted: Sat Nov 09, 2019 2:39 pm
by The Veg
I took a different approach with my Plus 2. The old horns were in bad shape, one of them making no sound and the remaining one seeming a bit feeble. I've been disappointed by modern air horns (especially with poor reliability of their compressors), but I have been extremely pleased with the Hella Supertones that I installed on my motorcycle a few years ago so I got a set for the Lotus. Sure, they don't sound period-correct, but this is a small and low car, lost in a sea of big chunky SUVs and pickups, and needs all the help it can get for getting noticed in close situations. I was nearly run-over in my former Esprit by a driver in a big SUV who probably didn't see me, so I want to make an unmistakable noise when I give someone the honk. The Supertones' sharp and nasty sound will make the soccer-mom in the minivan drop her latte into her lap when she tries to invade my lane! The aforementioned motorcycle informs a bit of my choice here too; I've learned from being on two wheels that assuming that you are invisible to other motorists just isn't enough.

Re: Mounting position of air horns

PostPosted: Sat Nov 09, 2019 7:18 pm
by Harvey

Nice to hear from you. It's been a long time since we traded posts. The Hella air horns are made in China and are available through many vendors. I can't remember where I got mine but probably through Amazon or one of its suppliers. I think I paid about $30-35 for them. The compressor is red with a black top like the trumpets.

The Veg,

I had a pair of Supertones on the Plus 2, made in India but of metal not plastic. They are indeed loud if that's the primary consideration for the horns. Probably even louder than the air horns. However, I didn't think the sound was right for the Plus 2 hence the air horns. Just a matter of personal preference.

I have, however, installed a pair of Supertones on my Elise specifically because they are loud and nasty as you say. I fear a collision in the Elise even more than i do in the Plus 2 because of its height or lack thereof.


Re: Mounting position of air horns

PostPosted: Sun Nov 10, 2019 9:07 am
by mikealdren
Grizzly wrote:If you have a later type small radiator the compressor will be mounted like this (Its a 2 seater but you get the idea)

I wouldn't want my air horns to be forward facing as they will get all the road much straight into them, Rohan's location looks better in this respect.