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Another air horn installation, this one with relay

Joined
21 June 2020
Messages
42
Location
CT
These days, low cars should have loud horns. Whereas the NSX is outstanding in nearly all respects, the horn note and volume is not one of them. I have a Stebel Nautilus on my Miata and thought it’d make a nice addition to the NSX.

I decided to use a relay to not risk overloading the fuse or oem relay in an emergency situation, particularly since I believe the brake lights are on the same circuit? Also, though I don’t know for sure, I think the horn will get more current and thus volume with the relay.

As prior threads have detailed, location is always a question. I figured that locating the air horn where the alarm horn use to be would be a nice solution.
414462302.jpg


First, I removed the alarm horn. I wanted to use the oem plug to connect to switched power #86 (+) and ground 85(-) on the relay. In this thread http://www.nsxprime.com/forum/showthread.php/210023-Horn-2-pin-Connector I learned that it was possible that a Honda outside air temperature sensor plug might do the trick. Went to a local pick in pull and after a very short time found a 2005 Civic with the plug dangling out the front grill. :) $5 later I was in business.

414462303.jpg


414462304.jpg


I ran the power using a 20A fused line to #30 (+) on the relay straight from the battery, back along the firewall and behind various plumbing on the driver’s side.
414462308.jpg

Power then leaves the relay to the compressor via #87 (+). For the ground coming from the compressor I used G202, which is one of the two body grounds under the orange plugs.
414462310.jpg

These grounds are hard to get to but for purposes of the shorter ground wire, I used G202 rather than G302, which are much easier to access on the other side of the compartment. Pictured here.
414462311.jpg


To get the horn to fit, I separated the horn from the compressor. (Got the idea from a Vespa Scooter forum!) Originally, I was going to try and run it down in front near the factory horns because once separated you can basically put the horn anywhere it fits but opted on putting it in the factory alarm location. I used a strip of aluminum with two holes drilled in it. One hole to bolt the compressor on and the other to mount to the car. I have no idea what that wheel well bolt hole is for but it was handy to have. Wanted to use the old horn threads but couldn’t make it work.

Separating the horn from the compressor is NOT as easy as it appears in this vid. https://www.youtube.com/watch?v=IbP2nwP8O7Q I almost separated the top of the compressor from the bottom before deciding to attack it with a heat gun and long screw driver.
414462306.jpg

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Other parts I used were some Straight Vacuum Connector 5/16" x 5/16 to make a fitting for the horn air intake and compressor hose attachment.
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In order to fit the horn back on the compressor, but lower down to fit the space, I had to cut again.
414462330.jpg

Got it all hooked up and am pleased with the result. The OEM alarm plug is between the relay and the horn.
414462333.jpg


Might sound better if I disconnected the OEM but I’d rather have too much than not enough. Vid shows the difference in the sound from a little over 50 yards.
https://www.youtube.com/watch?v=jfC7euyh3RY&list=UUyu3RTMQGsUzBFdkNOzDrog
 
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Thanks.

On the exhaust, Comptech header and RM Racing DTM. I like how it sounds too. :)

See here for more info
http://www.nsxprime.com/exhaust/ on that exhaust but RM no longer makes an NSX exhaust. Read somewhere that Billyboat made the same exhaust but it doesn't appear on their website.
 
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Attachments

  • 10 - Relay and compressor mount.jpg
    10 - Relay and compressor mount.jpg
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10 - Relay and compressor mount.jpg
 

Attachments

  • 12 - Horn mounted and ready to go.jpg
    12 - Horn mounted and ready to go.jpg
    216.1 KB · Views: 75
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First, I removed the alarm horn. I wanted to use the oem plug to connect to switched power #86 (+) and ground 85(-) on the relay. In this thread http://www.nsxprime.com/forum/showth...-pin-Connector I learned that it was possible that a Honda outside air temperature sensor plug might do the trick. Went to a local pick in pull and after a very short time found a 2005 Civic with the plug dangling out the front grill.
smile.gif
$5 later I was in business.

414462303.jpg

3rd horn, alarm horn location.  Note two wire plug.jpg

Male plug from 2005 Honda Civic air temp sensor.jpg

air temp plug from the top.jpg
414462304.jpg


I ran the power using a 20A fused line to #30 (+) on the relay straight from the battery, back along the firewall and behind various plumbing on the driver’s side.

fused - 20A - power line to relay 30 pin.jpg

414462308.jpg

Power then leaves the relay to the compressor via #87 (+). For the ground coming from the compressor I used G202, which is one of the two body grounds under the orange plugs. These grounds are hard to get to but for purposes of the shorter ground wire, I used G202 rather than G302, which are much easier to access on the other side of the compartment. Pictured here.

Body ground blocks, these on left side but I used right side for shorter distance.jpg
414462311.jpg
 
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Hey, can some administrator help me delete this thread. My pictures disappeared when picturetrail went belly up and I've made multiple attempts to get it back to where was but now it's just all FUBAR. This site is hard to work in, what with getting kicked off all the time, like every five minutes. LMK. Thanks. Dan
 
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