Air Horn Installation
From: uunet!sj.fore.com!trop (Troy Pummill)
Date: Mon, 16 Dec 1996 13:27:28 -0800 (PST)
Subject: MR2 air horn installation
Many have asked about my air horn installation, so here goes...
Materials:
Air horns and compressor (Fiamm Grand Prix, $25)
Electrical wire and connectors
Adhesive-backed tie wrap mounts and various lengths of tie wrap
Dense adhesive-backed insulation foam
Various tools to handle the above
Black spray paint
Rubbing Alcohol and rag
or
various metal fittings
screws, bolts, lockwashers
tie wraps
I'll try to keep this short. (that's a laugh)
I have no front license plate holder and the goal was to install
the air horns to be (nearly) invisible from the front.
First plan was to install the compressor and horns between the
radiator and the back of the bumper ( which is inside the air dam
and up ).
I pushed the compressor past the air dam and it fit through the opening
at the top of the air dam, until it hit the bumper. I could not find a
space at the front of the car between the bumper and the radiator that
would fit the compressor. Days of engineering down the drain, arrgh.
Instant reengineering meant jacking the front driver's side tire and
installing the compressor in the corner created by the wheel well
and the radiator fan housing. Looking from the top of the car, with
the radiator plastic shield removed, this is a space at the extreme side of
the radiator where you can see the ground. I now see the top of the
compressor.
I cleaned with alcohol this area and used the tie wrap mounting plates
in 3 locations to hold the compressor. Two of the tie wraps were attached
around the circumference of the compressor and an additional one through the
real mounting bracket on the compressor (which I should have used but didn't
because I didn't want to drill a hole into gawd knows where).
The latter tie wrap goes *up* above the compressor to help hold its weight.
I took the air hose and fed it under the radiator which placed it out
the front of the air dam very near the edge of the driver's side opening.
For electrical, I took (at someone's suggestion) and placed male connnecting
blades on the end of wires and plugged them snugly into the original
power connectors for the original horns. These were fed along the bumper
via tie wraps/mounts to the air hose location and then back to the compressor.
The negative was attached to one of the bolts securing a platic cover shield
underneath the car (I don't know what its covering, sorry).
The horns were blue, so I painted them black. The end of the small
horn fit into the slot at the upper of the bumper (if you put your
hand in the air dam and go up, you can feel the space between the
top of the bumper and the inside of the plastic where the little
toyota emblem is). I worked the end of the small horn into this
slot. This placed the other end (the bell) right at the bottom of
the bumper. I secured the middle of the horn with tie wraps/mounts to the
bumper metal itself (after cleaning with alcohol). You cannot see the bell
of the small horn at all unless you look *up* the air dam.
I wanted to long horn to be parellel with one of the black verticle
struts in the air dam. It was too short to go from the slot at the
top of the bumper all the way to the middle of the air dam, so I
placed the bell in the small notch created where the verticle
air dam support meets the middle horiztonal run. With the bell in
this notch, I attached the middle of the air horn to the bumper
with cable ties and mounts.
It is very difficult to see the horn at all from the front because
it is painted black and follows the driver's side verticle support
in the air dam. (I will have to touch it up as the spray paint
comes off too easily. I must have missed some step in priming/preping
the plastic air horns for spray painting, oh well).
I used tie wraps and mounts generously to keep wiring/horns/air tube/
compressor and connectors in place. I did have to remove the
driver's side original horn in order to complete the installation
with the supplied amount of tubing.
I also used liberally the adhesive insulation foam everywhere to ensure
that none of the components would rattle.
I installation was < 5 hrs, mostly because the original installation
plan failed. Working under the car in that small space is
very time consuming.
I'm happy with the installation except for mounting the compressor
with tie wraps. The adhesive mounts are very strong (I wanted to
move one and couldn't get it off), but I'd prefer a drilled hole
with a mounted bolt. I might try this after the feeling returns
to my hands and arms :-)
NOW, since this was written, the compress fell out. It seems that
I didn't calculate that the two-sided tape might fail from the
tie-wrap mount side. Horns are fine. I'll be having a hole drilled
at my Toyo shop on Monday to have the compressor properly mounted.
INSTALLATION OPTION 2
---------------------
OK, Toyota installed the compressor and, in the process, pulled the
tie-wrap-adhesive-back-mounted air horns off. (ugh).
So here are the second installation notes. This installation is
*much* more solid.
Jack up the left front wheel of the car. Remove the four screws
on the bottom of the mud guard, and the one screw holding the same,
which is half-way up the fender. The removal instructions are outlined
in the owner's manual for replacing the side marker bulb.
Once the screws are removed, you can pull back the mud guard and see
up into the area which houses the undeployed headlamp. Near the
bottom of this area is a small cylinder. The Toyota guys fashioned a
bracket from metal and mounted the compressor to the metal and the
metal to one of the bolts holding this cylinder in place.
There is a small opening which can be used to route the air/electrical
out of this area and up to the front of the grill via the path
outlined in the instructions above.
To re-install the horns, I went to Orchard Supply and got some metal
fittings. One which has several holes and extends upward with a
90 degree twist. Another which was flat and thin, and had holes every
half inch or so.
I mounted the small horn to the (mfg'd) 90 degrees twisty metal with a bolt
and lock washers. I also cut a small bit of the straight metal
and gave it a 90 degree twist with a pair of pliers. This metal
I attached to one of the holes on the opposite end of the 90 degree
twisty metal. I mounted the long airhorn to this hand twisted
section.
Once I was resonably sure this was the appropriate arrangement, I took
off the long horn and started installing the horns again.
All the the metal, and the mounted small horn was placed up in the
air dam/radiator. I attached the bottom section of the 90 twisty
to the location where I have removed the original horn, using a
regular tie wrap to secure them together.
I then made some final tweaks (with pliers) to the hand twisted
metal and used tie wraps to mount the long horn to the end of the
hand twisted metal.
To sum it up, from bottom to top, the bottom of the long horn rests
in the middle support of the air dam. It is attached to the hand
twisted metal via a tie wrap. The twisted metal bends 90 degrees
and joins the manufactured 90 twisty metal via a bolt, lockwasher,
and screw. The mfg 90 deg. twisty metal is fastened to the
location that previously held the OEM horn, which is parellel to the
front of the car. From here the metal twists up 90 degrees (now
perpendicular to the front of the car) and
is joined to the small horn via bolt, lockwasher and screw.
The result is that the large horn is perpendicular to ground
and the small horn is at about a 45 degree angle and is
stuffed into the upper corner of the air dam opening.
You might want to contact Matt G, he installed his compressor under
the headlamp, but he used adhesive-mounted cable ties as in my
first installation......
please let me know if you have any questions...
Troy
trop@fore.com
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