Audi A4 B8 Train Horn Install (my first build thread post let me know if you see something or need additional info)
Alright guys, this thread is my official installation guide for a train horn on our Audi A4s. I would like to thank Michaels and Lowes for the excessive use of their parking lot, lmao, but for real no joke finding a good place to do work. Below is a set of items you will need depending on your train horn purchase.
Train Horn Installed: I went with Vixen Train horns Model: VXO8315/3118B. (Heads up, though customer service was great, I had to go back and forth with them on the quality of their tanks. The first two they sent me which they claimed to have gone through quality control prior to shipping had leaks in them, obvious leaks, which just makes a frustrating situation. Who buys something and wants to wait, and wait again to finally be able to install a working product.
Anyone looking to sponsor more builds hit me up at [email protected]
Upcoming projects open for sponsorship:
CTS Boss 500 Kit (with Air intake)
Eurodyne Maestro Tuning package software and hardware
Wheel Spacers 5-10mm
Front lower adjustable control arms
Adjustable shocks
Red coil packs
PA system
19 inch rims
Current Installs:
GFB DV+
CTS IC
GFE Magnum Pro-dry Air filter
CTS catch Can
Racechip GTS
Tools: (may Have missed some sorry)
Car Jack (if not intending to pull of bumper)
Drill
Variety of Steel/titanium drill bits
Wrenches
Deep sockets wrench 13-17 m
Wire cutters
Electrical Tape
Fuse taps Fuses
Kill switch
It all started at Michaels with my trusty Rhino Ramps. I was originally trying to find a place to mount the horns in the engine bay as you will see but that quickly came unreasonable due to the excess heat of the engine and lack of room.
20220306_111502e.jpg
Long story Short you won't really need the rhino ramps if you do it the way I list below.
1.) With the hood open, when looking into the engine bay, you can see by the windshield and brake fluid reservoirs there is a black cover with a little battery symbol on it. Remove the entire piece by removing the two plastic screws (flat head screwdriver).
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2.) I mounted the horns on preinstalled studs located within that bay (one of the many shown with a green arrow) between the cabin and engine as you can see for the two smaller horns. For the larger horn with the solenoid, I had to install it by drilling a hole through the engine bay through the firewall material to the little bay (green arrow). (I Utilized the same size nuts and bolts that came with the horn but with longer bolts for the large horn being I installed the horns separately.)
***prior to mounting the horns, I would fit at least one of the tube ends into the horn for ease later*****
20220306_120230.jpg20220322_135546e.jpg
The tubing supplied is ¼ in OD tubing which slips right into the respective fittings. I ended up buying upgraded tubing that could withstand higher amounts of heat and pressure as the first tube used wilted enough to block the air. I did the local connections first on the horns and then installed
My entire goal was to mount the entire system, so it is not visible to the naked eye even when looking at the location. Being an A4, not the S4, we have an extra cut-out location of where the second muffler would be. It’s covered by a little plastic cover which can easily be removed. This is the location I mounted my train horn compressor and tank. (add red arrow to rear pic of where install occurred)
Picture of the wheel well without cover with compressor and tank installed.
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The Muffler well with the cover on. It protrudes out just a little so some modifications/cuts had to be made to the plastic covering.
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I proceeded to mount the Tank and the compressors. I originally was using a car jack and just lifting the passenger rear side enough to for me to work under, but long story short just remove the bumper.
3.) Remove the car's rear bumper for easy access and plenty of workspaces. Youtube the process it is super easy, takes like 5-10 minutes tops, and makes the job so much easier.
5.) After the bumper was removed, I emptied the trunk and removed the contents of the wheel well to expose the top of the emptied wheel well.
6.) Drill holes and space out the tank and compressor
a. Be careful if you plan to install in the same location as there are many electrical components that you do not want to F with.
The Inside of the luggage fuse box compartment where the bolts support the hanging compressor: note the wires were connected after securing it towards the end of the build.
20220513_114718e.jpg
7.) Mount the compressor
a. Due to the spacing available the entire process was not recorded or very well photographed. But looking at the location and if you’re looking to mount there like me here are some notes.
b. The compressor will be free hanging (due to a bar on the underside next to the blue highlight) so use spacers to keep a firm connection. (Red arrow Showing Free hanging, So I have a bolt from the top secured with a washer, going through the hole I drilled within the luggage compartment fuse box area, secured with a washer then a spacer, then a washer prior to pulling the bolt through the compressor, but and finally a bolt. Maybe overkill but is secured it tightly and removed the unwanted space I had.)
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c. Save enough space out from the side of the car (the outer-side) so you can work on all 4 screws. I mounted it to close to the outer side and the underlip made it impossible to secure the one bolt hence only using three bolts. *** red Circle of area where I lacked space***
Compressor mount location and side lip showing distance for bolt e.jpg
8.) Mounting the tank
a. I mounted the tank to the underside, on the side, of the wheel well. note the battery and wiring location pre-drilling
b. Tank use video to reference location: 20220318_193844 (13 seconds to 18)
Picture from Topside of the wheel well
Wheel well pick topside.jpg
Tank from underside mounted on the side of the wheel well (location depicted in red)
Attachment 270599
Tank and compressor installed in the muffler hub.
Attachment 270600Attachment 270601
After installing the tank and the compressor I went ahead and did the electronics. I used a multimeter to evaluate the various fuses on the driver side and luggage fuse boxes. On my car the fuses are active whether the car was on or off, so I installed a kill switch for the compressor (aftermarket buy). For install I would just follow the diagram provided with the kit, it was easy and made sense. The final connections were the hoses which I had to buy additional length for to make it from the tank in the back to the horns in the front.
From the tank outlet I choose, I connected the ¼ OD hose , and pulled along car follow path in red.
Attachment 270602
Pulling from the center I pulled the tubing toward the outside to go along the out fender.
Attachment 270603
Into the fender underside
Attachment 270604
Out the fender protection into the inside wheel well cover passenger side.
Attachment 270605Attachment 270606
Out of the wheel inside plastic cover into the engine bay compartment
Attachment 270607
.
From there you should be able to see the hoses and pull them to the solenoid horn, which will then supply the remaining horns with air upon pressing the button.
Electronics you will have to figure out what works best for your car and provides you the 12V needed (connection wise I used the provided diagram from the instructions). The horns were simple I connected them to the driver-side fuse box with a fuse tap 10-amp fuse provided. I pulled them from the outer compartment to the cabin by going through the driver-side firewall. (YouTube it there are a ton of videos and it’s very easy.)
Red arrow shows the grounding point.
Attachment 270608
The connections in the back were even easier, again following the wiring manual diagram provided, and with additional wiring, I connected the underside compressor to the luggage compartment fuse box by pulling the wires through a grommet. (red arrow)
Attachment 270609
I circled the grounding point I used. And the fuse tap I placed a red box around it.
I connected all these to the kill switch and shit there you go.
Attachment 270610Attachment 270611
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Originally Posted by Theiceman
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