Ok, so i really want to install air horns on my scion tc but i have no room to put in a compressor and tank (i have subwoofers). I have an extra 48cu in 3000k psi high pressure air tank and was wondering if i could run the horns off of that? I know ill have to fill it often but im willing to do that. I just need to know if i can even do this and if so what all do i need to install it?
Yes it has been done. There are a few threads if you search “scuba”.
Welcome to the forums.
Welcome to the forum.
Are you sure it holds 3000k PSI because the K adds 3 more zeros making it 3,000,000 psi. 
(I’m being sarcastic)
Haha yeah i meant to just put 3k but wasn’t paying attention. How many times do you think i could use the horns when the bottle is that small?
I’m not familiar with scuba tanks nor their cubic inch rating. I know you get more air using Ln2 than Co2. I know the owner of “Power Tank” and his are rated 5 pound & 10 pound Co2 tanks.
I hope you have readily available source for refilling the tank. My concern is running out of air when you need it the most. Air horns aren’t critical but putting air in a tire is.
Anything is possible if you put your mind to it! lol. Those other guys know what they are talking about. Giving you some encouragement! Dan is right though! Make sure to check on your psi Gage on the tank once in a while to ensure you have enough air in there to last you. Other wise you will need to go to where ever you need to go to refill that kind of tank. Me personally, Gotta have my Compressors!
How many honks do you think i could get off a 48cu in tank?
If 48cu means 48 cubic inches then it’s about 1/8th of a gallon. Taking a wild guess I’d say you’d get less than 5 blasts. You also need to consider how the valves and horns will react to air that cold.
Its high pressure air not co2
Even air at 3000 PSI is going to be cold when it’s released. When we drain our shop compressor the port freezes occasionally and it’s only at 175 PSI.
I run a 1200$ paintball gun off of it so if that can take the cold air a train horn probably could… The internal of the gun are a lot more sensitive.