At the very most you have 0.441" ID and you probably have between 0.300" and 0.400" ID depending on the fittings that you are using. This may not sound like a lot but even a drop from 0.500" ID down to 0.400" ID results in 36% less air flow through the line. Go down to 0.300" ID and you lose 74% of the air flow! To find out for sure how much you are losing, you need to measure the actual ID of the smallest fittings in your air flow path. I have seen some male threaded 1/2" NPT fittings which have an actual ID of only 0.250" and others which are “high flow” will have a lot larger openings. Compression fittings in general have smaller ID values but there are many brands, sizes, and types of fittings out there so you have to measure yours to be sure.
You would be much better off going to a larger tank than running high psi and cutting it down with a regulator. If you must use the small tank and higher psi then you should at least use the largest air line possible. PSI and flow rate are not the same. You cannot expect a higher psi to automatically offset the flow rate restriction imposed by smaller fittings. You can offset it by a little bit by going up on the pressure but the narrow air path will limit the flow rate the most.
Dang. See, there’s no way to know that as a novice horn enthusiast. So I guess until someone shuts me down with their horn or I can blow my horn with the windows down without hurting my ears, then I will stick with what I have. Where is a good place to get high-flow fittings? THEN, I wouldnt need to re-do EVERYTHING, right? Just the flow from tank to horn right? because the leader hoses are small as hell, and everything else has reducers/ (i.e. guages, etc.) I mean, thats gotta be the only place Im losing. I can start collecting my fittings one by one, and just change everything at once. But tell me, if I have 1/2" ports on my tanks and everything in between, how large can I go with the hose?
Yeah, I had the same frustrations. I lived with a sub-optimal 1/4" ID system for about 2 years because I made assumptions that turned out to be false. Then I upgraded to a new horn, 3/8" ID, higher psi, and a larger tank and noticed only marginal improvement. So I did a lot more research and ran my own calculations and realized that 1/2" ID would make it much better so I upgraded a third time. I was expecting an improvement but I was not expecting double the volume! It shocked me just how much difference the air line made, which is why I posted my advice to this thread and several others - to share the tips.
The main thing is to keep it all 1/2" ID from your tank to your horn. Using any fitting with less than 1/2" ID will reduce the total air flow of the line. So put the smaller taps and accessories on their own branch which is not in the main air path - look at my system diagram (link is in my signature) for an example. I combined my gauge, sensors, safety valve, etc. all on the same manifold or tees which are branched off of the main 1/2" ID line so the smaller manifold and tee size won’t impact the air flow from the tank to the horns. You can replace hoses and fittings one at a time but you won’t see the full benefit until it is all 1/2" ID with high-flow fittings along the way. You can measure the actual ID of any fitting before you purchase it. I had to make about a dozen trips to hardware stores and shop online before I found what I needed but the parts are out there.
But in the end if you are happy with your horn volume then don’t do anything. Just know that it is possible to improve your setup if you ever desire to do so.
Ok. I wish there was just one other person I knew with a REAL train horn that I could compare it to.
Man I am eating this up man. What size air line do I need to have an ID of 1/2" on the air line? The air line has to be greater than 1/2" right? if theyre going by OD? I wanna upgrade my line already. Seems like it wouldnt be that much. Only thing that would suck is the fitting ON the horn because I would have to unmount the horn entirely.
Just drive to the nearest railroad crossing or bridge and ask the locals what time the trains normally run through. Go back on the next schedule and you can compare to the real thing!
If you go with rubber air hose instead of nylon tubing then the air hose is rated based on ID. So a 1/2" rubber air hose is closer to 3/4" OD with an actual ID of 1/2". Then you can get all brass NPT fittings which are also rated based on ID, however some brass fittings will have smaller ID than others due to variations in the thickness of the metal. I used a basic 1/2" NPT hex pipe nipple coming out of my air tank into a 1/2" NPT pipe tee, then one leg of the tee connects to a 3-way 1/4" NPT manifold for my gauges and accesorries. The other leg of the tee connects to the 1/2" air hose with a 1/2" brass hose barb that had the largest ID I could find. Next comes a pair of 1/2" high-flow quick disconnects which are HUGE, with another 1/2" NPT pipe tee in between them. This allows me to quickly remove my air tank for use outside the vehicle and also to remove the whole compressor mounting board if I need to use the entire truck bed. From the compressor board the 1/2" air hose goes into another 1/2" pipe tee with each leg feeding a different horn set, both of which have 1/2" air valves. So the air line is 100% 1/2" ID from the tank to the horns and it only steps down as it enters the individual trumpets. If I sound one horn at a time then they get the full 1/2" capacity but if I sound both at once then they have to share the air. Works great!
Do you lose any air with those ‘tee’s’ in there? I read that ever 90 degree bend gives you a psi loss. But, Im not expert. Reading is how I got in this thing in the first place lol.
SO far I just have a set of Shocker XLs with a VIair 400C compressor and 2 gallon tank on an 06" Tacoma standard cab. Ive put in about 4 hours on the kit and 2 hours trying to find the best spot for them. Started at 8pm and worked till midnight only to wake up half the block with the first test. Im ordering a set of psychoblasters this friday so there will be somemore work for me then aswell. The shockers are mounted under my bed so Ive gotta find a good spot to fit the blasters.
Technically every inch of hose or tube, every fitting or adapter, every valve or connection point, and every bend in the line adds resistance to the line which can result in reduced psi. In reality the actual drop in psi from the tank to the horns should be minimal, probably no more than 2-4 psi total, as long as you use high quality components and your system doesn’t have any leaks. I confirmed this on my setup by measuring the pressure with a manual gauge on my tank and an electric gauge with the sensor mounted about halfway along the main air line. The manual gauge and electric gauge are always within 1-2 psi of each other and sometimes the electric gauge reading is the higher of the two so I suspect that the fluctuation is variance introduced by the gauges rather than an actual drop in psi along the line. You can do the same measurement yourself by temporarily installing a second gauge at the end of the line if this worries you but you should find that there is little if any drop in psi.
It is much more important to have a high air flow rate which allows the most air to be available to the horns in the least time. Using an air line with a larger ID significantly increases the air flow capacity of the line, sometimes doubling it or even more, so to optimize your setup you should use the largest ID possible and ensure that all hoses, fittings, etc. do not reduce the ID beyond the desired size.
One other thing to be aware of: using a high capacity air line will allow the air to flow to the horns much faster and thus your blasts will be louder but you will also deplete your air supply quicker. And on some horns the increased flow rate can change the pitch or tone of the horn. This is the price you pay for the extra decibels but it was well worth it in my case.
[QUOTE=wileecoyote;31713 And on some horns the increased flow rate can change the pitch or tone of the horn. This is the price you pay for the extra decibels but it was well worth it in my case.[/QUOTE]
I ran into this as my air was depleted the pitch changed when I used 200 PSI.
Knowing that 200 PSI was harmfull to the K5s, I install A high flow 1/2 inch speedair Regulator and set it @ 140 PSI and my horns stopped the high pitched squeal and my long blasts are very consistent and I get longer blasts. Now my horns sound like they are suppose to. I have 16 gallons of air on tap but I rarely turn on the added 7 gallon tank as I can’t honk it that long without people here in So. Cal. wanting some sort of revenge.LOL
R…
So, You are using rubber hose and hose clamps? Maybe I should look at your pics or somethin instead of asking all these questions. lol. thats my bad.
Doesnt the larger air hose add volume to your tank? Ill be upgrading to a 10 gal and one more compressor. Dont ask why the addit’l compressor, I just like the efficiency. And speed. I can get about 6 good blasts before the comps kick in, and then they only run for 1 minute and then Im back at 205.
So You’re running yours @ 140. I have mine regulated at 150. I mean my k3 is LOUD. And personally its my own version of loud because I have been the person behind the button. I dont have a desolate testing area here in flat-country. There are people everywhere. So thats why I dont have any videos and all that yet. But what i DO notice is that I dont really turn heads from DOWN THE STREET. Its normally when i get CLOSE to whatever it is Im honking at. and at the same time, I always do short, short blasts. I never really lean on it unless im in a tunnel or somethin like that. I might not be giving that big bell time to wind up.
I am using Goodyear rubber air hose as noted in my signature and my system diagram. The hoses connect to the brass pipe tees via large brass hose barbs which have a fairly thin wall so the ID of the barb is very close to 1/2". Everything else in the main air line is 1/2" ID or larger.
A larger hose ID and/or a longer hose between your tank and the valve will allow more air to be stored in the hose beyond what is stored in the compressor. So technically the answer is yes, although the amount of compressed air which sits in the air line is probably not more than 0.5 gallon at the most. If you used a super wide air line like 1" ID or super long air line like 30’ then it might give you a significant amount of extra air, in effect serving as a small extra tank, but it would also increase the resistance along the air line and increase the risk of leaks. If you used a larger or longer hose between the valve and the horns then this would lead to a delayed blast with a softer sound at first until the air pressure and flow rate built up to full capacity.
My solenoid is mounted on my tank and has 1/2" npt fittings, which have an ID of 3/8". The solenoid has an ID of 3/8". The hose between my solenoid and my horn is only about 2’. I really doubt that increasing the ID of the solenoid would change the airflow at all. I will try to get a video tomorrow.
I am not sure about the setup on your truck since your runs are so short, but 3/8" ID still results in 44% less air flow capacity when compared with 1/2" ID. I was skeptical of this myself which is why my first upgrade was from 1/4" ID to 3/8" ID but I had very marginal improvement. When I stepped up from 3/8" ID to 1/2" ID I noticed roughly double the volume and it blew me away!
The biggest factor is the consumption or flow rate of your horns. If your air line always supplies more air than your horns can consume then you will have maximum volume. If you go with less air than the horns consume then you might still be happy with the results but it won’t be optimal. There is a reason HB sells the Shocker XL upgrade kit with 1/2" ID valve solenoid and larger air lines…
From what I read, The nathan (K) series horn is designed to sound of properly at pressures between 90 and around 150 PSI. If you really wanna find out about pressure drops and hose and or pipe size,Check out Air Chimes web site
under tech data and I think you will find what you are looking for.
I checked their tech documents. They have something related to running shop air through schedule 40 metal pipe. They do give you a comparison value for tubing but the data and measurements are based on schedule 40 metal pipe, thus the measurements and figures are not directly applicable to rubber air hose. If you find a similar document for rubber air hose, nylon tubing, and pressure ranges related to train horns then let me know. I would love to check it out.
Air supply line should be one size larger than the inlet connection of the horn.
Air supply line should rise continuously through well graded piping, free from pockets and long
horizontal runs.
Air supply at the horn should be clean and dry, install separators, traps and strainers to maintain this.
Air supply should be taken from the top of the air tank or main supply line.
Use thread seal sparingly and on male thread only.
Avoid the use of elbows if possible. (General rule of thumb is 3-psig (0.2 bar) drop on 120 psig (8.2
bar) per pipe elbow). Long radius bends are less restrictive.
On extreme long runs, a buffer tank, located close to the horn, will compensate excessive pressure
drop. Pressure drop at the horn, should not exceed 15 psig (1 bar), when blowing. Install test gauge
at the horn inlet to check this when installing.
Install shut off valves where necessary to facilitate servicing.
Install operating valve close to horn for sharp concise blasts - Sound should not “trail off” at the
completion of a signal.
Before connecting the horn and valve, blow out all lines thoroughly, tapping pipes with hammer to
free loose scale and pipe chips.
Outside runs that are exposed to cold weather conditions should be well protected or consideration
given to electric heating of the pipe.
Control valve should be rated for the weather type. Otherwise, it should be heated to prevent
freezing.
If the above procedures have been followed, the horn will sound loud and clear when the manual valve
is pulled or the solenoid energized.
Item 1 is very relevant: “Air supply line should be one size larger than the inlet connection of the horn”
I suspect that item 6 (psi loss for elbows) refers to use of schedule 40 metal pipe and fittings, so I am not sure this directly applies to brass fittings and rubber air hose, especially for the shorter distances encountered in our train horn installs. My total run from tank to horn is no more than 10’ long and it has 2 elbows in it, yet when I measure the pressure at the middle or end of the run it is the same as the tank pressure +/- 1 psi.
Item 9 is key too - keep the valve close to the horn.
