Stock air horn replacement

[hood297]

Hey guys, tried the seach forum and couldnt find much. I
Am replacing the stock air horns with larger 3 trumpet horns, ive test rigged them
On the truck and it just doesnt seem that loud, is there a pressure regulator on the air horn system limiting it? It just doesnt seem to be blowin' like it should with 120psi in the tanks. Would the stock 24v air solenoid limit it? Or will it need a larger supply line?

Thanks for any insight. Oh and its a 1970 am general
M35A1

 

[RDUKW]

The first thing I would look into is a larger solenoid that is spec'd out for your horn set and a feed line that matches. If your getting a 100+psi you have more then enough pressure and are just lacking a little on the volume.

Ryan

 

[hood297]

well the air horns came with a solenoid valve about the same size over all with the same size fittings ect but 12v, so I was able to just swap the old one on my stock horns to these. So it wasnt designed for much bigger of a supply line and I know its got plenty on psi behind it, and it did the old horns just fine.

Maybe just put the solenoid valve that came with the new horns to see if maybe the stock 24v valve doesnt open up enough or allow enough volume? guess its something else to try..

 

[hood297]

Well switched the solenoids, just for a couple tests. And no difference, guess it has to have more than 110-120 psi. Seems kinda odd. Think its that or a cfm volume issue?

 

[steelandcanvas]

Anything in the paperwork with the horns that would indicate the required SCFM? I'll bet it's a volume issue if you have the required pressure.

 

[RDUKW]

If you have access to shop air just fire them off with that and it will give you an idea if the sound is really off. Another thing to check is see if the original solinoid is full port and this can be done by releasing ALL air and remove the valve and have some one push the horn button and look thru the valve to see if there is any restrictions. How big are these horns and what size fittings are on them? I have had large horn sets on yachts sound weak and the culprit was 9 out of 10 times the solenoid being to small.

Ryan

 

[hood297]

Well i got them second hand from a friend. Like i said i used the solenoid that was installed on them when i got them and got the same result. The solenoid that came with them has the same input and output size as is on the truck
Stock, just wasnt sure if there was something before the solenoid valve that retricts the pressure.

And theres no info on the horns, im no stranger to airhorns, especially marine grade items. Got a set in my jeep from a 72' hatteras motoryacht and they blow wayyyyy better than these.

 

[Squirt-Truck]

Any specific reason why a 3 trumpet? You do not have enough volume (as stated above) for that rig.
A single trumpet horn is way loud enough. I have a 30 inch Grover on Squirt and personnel outside the cab can FEEL it from 100 feet and hear it for over 1/4 mile.

 

[ApopkaFL]

I have a set I am going too bypass the solenoid valve and install a hand valve for mine so I can regulate how much air goes into the horns. That way I can control the pitch and sound of the horns.

 

[PowerstrokeNC]

I have had train horns before with less than 100psi and they ran just fine, for my setup it all came down to volume of air, I had to have a 3/8" supply line or no workie. I think the stock one on the deuce is 1/4" that might be your bottle neck.

 

[Jake0147]

What happens to the air pressure gauge on the dash when you hit the horn button...

That pressure drop (or lack thereof) will be a good indication of how far you've got to go back to get an adequate supply for three horns. I'll bet it's right to the tank, but that will give you good insight.

I've also seen issues on this forum with air governor performance being affected by air restrictions from this air circuit on the firewall which supplies the governor, gauge, horn, etc. Maybe there's a partial one starting? Not a silver bullet, but the fitting coming out of the tank could be considered suspect at least. A restriction (but not outright blockage) there will give you excellent pressure under low or moderate air usage, but when you're burning up a lot of air, the pressure's gonna go in the toilet. That should reflect on the gauge, which is after the common (well, not common but "known") trouble spot, but before the horn.

 

[Truckoholic]

I've got some of these on my M813. They were a big hit when I put my truck in the Portola Railroad Days parade last Saturday

HornBlasters Shocker XL Train Horn

I just plumbed a 3/8 inch line right off of one of the tanks, and ran that straight into the 12 volt solenoid valve that came with them, and got a 24 volt relay that I wired into the wiring going to the existing horns, and drew 12 volts from one of the batteries. So the result is, all six horns blow when I push that horn button, and man is it deafening!