Darrell Lee (d...@awaiter.com)
SE-R engine compartments are crammed full, so you're probably
wondering _where_ you're going to find space to put your air horn.
I'll tell you where I found mine, but good luck.
First, count up your nuts and bolts. If your horn doesn't
have enough mounting bolts for the compressor and its two or
three horns, buy them ahead of time. I also had a bracket
(about 6" long) with a slot in it for variable mounting of
the air horns (from a previous installation). It was handy.
Next, you need a soldering iron and 60/40 resin core solder
and about 3' of electrical wire to extend the original horn
wire. Get some black electrician's tape (or shrink-fit
plastic insulator) to keep the bare wiring from shorting.
Get a blade connector for the compressor ground wire (find a
dangling one off your car or off a junker). If you're a
neatnik, buy a spade connector for the other end of your
ground wire. Make a ground wire about 8" long with blade
connector at one end (spade at the other is optional).
Buy a box of 15 amp fuses, too. 200SX SE-Rs use mini blade
fuses. Classics may use standard blade fuses (I don't know).
Step 1. Mount your air compressor. On my 200SX SE-R, there
was a lot of space on the left fender. I drilled a hole
through the reinforcement groove for mounting. (When you open
your hood, this is the innermost flat area of the fender).
Even though the only bolt I had handy was about 1-1/2" long,
and it sticks up through the groove, there's no interference
with the hood. Drill the hole large enough to get your air
compressor mounting stud/bolt through it. Put the bare or
spade end of your ground wire around the bold and snug down
the nut/locknut/washer-nut to hold the compressor.
Step 2. Extend your original horn's hot wire to the compressor.
This requires some soldering skills, although you can crimp
the wires with solderless connectors from Ratshack if you're
electrically-challenged. I recommend solder, as you'll be
pushing 15 amps through the circuit. Insulate your bare solder
connections with electricians tape or shrink-fit insulation.
Plug the hot and ground wires into your compressor.
Step 3. Mount the air horns. You want them outside the
engine compartment, or the sound gets blocked by radiator,
block, fenders, etc. I removed the OEM horn and bolted my
slotted bracket there. The other end of the bracket holds
two air trumpets pointed downwards. I removed a bolt from
the hood release lever mount and put my third air trumpet
Step 4. Connect the air tubing from the compressor to the
Step 5. Replace the stock 10 amp horn fuse with your 15 amp
fuse. I've been told the relay is rated at 15 amps and your
compressor is going to draw >10 amps, so put a 15 amp fuse in.
On the 200SX SE-R, the fuse I'm talking about is in the fuse
box in the engine compartment aft and inwards from the battery.
Step 6. Blow your new horn. If no noise comes out, you
probably reversed your hot/ground wires and blew your fuse.
Reverse the ground/hot wires and your horn fuse (you did buy
a box of 5-15 amp fuses, right?) and try again.
Paul R. Detjens (p...@value.net)
Comments to and Excerpts from Darrell's instructions:
I would strongly recommend using the relay that came with the horns
and using the existing horn circuit only as the trigger to the
relay. This allows the compressor to get the current it needs (=
louder horns) and avoids the problem some others have had with
blown fuses from running too many amps through the original horn
circuit. (You don't want to find out you have no horn when some
idiot is coming right at you! ;-)
I would also avoid the solder because the vibrations of your car
will shorten the life of this connection. The amperage shouldn't
be an issue; the spade connections are good enough for the rest of
the circuits on the car.
The new circuit for the horn (per the Hella instructions) couldn't
be simpler: 12V from battery to relay, then to horn, then back to
ground (I used neg. terminal of battery -- see below). Another
lead from the relay goes to the same ground. I used 12 ga wire
with spade connectors for the main circuit, 14 ga for the trigger
from the original horn, again with spade connectors (avail. at any
auto parts store).
Drilling a hole through your fender and creating a decent ground there
encourages rust. A simpler way is to use existing mounting holes, and run
the ground back to the negative terminal of the battery or other established
ground location. I was able to replace two of the plastic "snap-in"
connectors on the fender splash shield with real bolts and nuts, and used
these to mount the horns and compressor.
Another very critical point to make is that the compressor needs
to be mounted vertically or the motor will prematurely burn out
(as experienced by Larry Weeks and recently by Pat Tilli).
I used a slotted bracket from an old light fixture. Bent the wings
around, and mounted the horns on the ends. Looks ok, works great.
Can only see it from under the car. I'll probably paint it to
match one of these days.
I'd be concerned about spool up delay with this distance between
compressor and horns. I mounted the compressor about 8-inches from
the horns and have *no* noticeable spool up delay. My horns are
low, and shoot to the side below the front splash shield. There
really wasn't room behind the nose of the NX for an clean mounting
arrangement (although Larry Weeks did it there, and is now thinking
of moving them). The sound is plenty loud and is not
muffled by the radiator or other engine components. I tried
different locations before securing the horns in order to see if
they would be muffled; I could not tell any difference in volume
between the various locations I tried (then again, I was probably
mostly deaf after a couple of toots ;-).
Some more data:
I purchased my Hella double air horns from Imparts: Part# 26023, $25.00 +
$3.50 S/H. 1-800-325-9043. The package came complete with a relay,
brackets and hose. I supplied the wire, fuse, spade connectors, and the