I just bought a rebuilt K3HA and have NOTHING to install it yet. I’m wondering if it would be a good idea to mount the horns where the spare goes and point them down at the ground. I have a Dodge 1 ton.
And what size tank should a guy run? Is 10 gallon enough? Thanks…
It will disperse the sound in all directions not just forward/backward etc. It will still be extremely loud. 10 gallons should be fine. depends on how long you honk/how many honks you take.
What twist said…
But they will hang pretty low.
Are you a member on DTR or CF? Your screen name seems familiar.
i run 117 gallons. it seems to work well.
Dodge Cummins owner here, too.
I have my K3LA pointed down and mounted to the frame rail near the fuel tank. I’m running 5 gallons of air and I’m heard at a mile and a half.
Trust me, you’re going to love them.
Hey MarineOne,
I’ve looked at your install post but for some reason it has no pictures (at least on my computer).
I was thinking of mounting down because it would keep out snow and mud, and it would sound equally in all directions. Otherwise I’d have to mount them really low to get them under the framework of the truck, well, they’d be the lowest thing down there :D.
Metallicajunky: That is some air you have there. I don’t think I want to advertise that much. I do have an eighty gallon LP tank that fits crossways in a pickup bed though… Nah, I use my truck for truck things and couldn’t give up the bed space.
Cumminshunter: I’m on the DTR. I see you there too, it’s a good place.
Now for air… should I just get a kit with a Viair 450? I want a mechanical valve plumbed in the cab somehow. I think I’ll run at least 5/8" lines.
Try it again, it’s working fine for me … or just goto my album on here and you’ll see them.
I just installed my K5LA. I mounted it where the spare tire used to sit and it is mounted facing forward with a 20 degree angled downward. It is Freaken LOUD. I think the angle makes a difference because the shockwave is hitting the ground and not straight to the undercarriage of the truck. I have a 7 gallon tank and 2 Viair 444C’s Compressors. This works good for me - I get about four - 5 second blasts before it psi falls from 200 to 140. Then it usually takes a little over a minute to recharge the tank. I can post picks if you need.
Are you putting 200 psi to your horns or do you have a high flow regulator??
I pressurize the take to about 190-200 psi and have a hose that runs directly to the selinoid valve, then a hose from the valve to the horns. I assume I am running a full 200 psi to the horns since I have no regulator.
I thought the K3 should run at about 125 psi. I wonder if too much pressure can hurt the diaphragms. I want to run mine at 125 psi, and right now I’m thinking of getting a 150 psi pump and running a 5/8" hose straight to the horns, well through a GW valve anyway… 
150 -vs- 200 psi
Good read by some respected people:
http://www.trainhornforums.com/showthread.php?t=3682