Finally installed my p3s on my 250 this weekend (pics coming soon) and when I blow them there is a squeal at first then the full train horn sound and then when I stop blowing another squeal. I have the solenoid less than a foot from my tank and probably less than five feet from my horns. I am making an educated guess based on my research on this forum that it’s the initial low pressure at first and the drop in pressure at the end of the blow is making them squeal. Im running 1/2" line the whole way and I’m using one of the side inputs on the horns at 150 psi. Curious if my educated guess is correct and if there is a way to fix it without moving the solenoid. Also curious if the input you use on the horns will affect the sound and loudness. Mine aren’t as loud as I thought they would be but then again I haven’t sounded a long blast yet. Guess im just a little discouraged because the squeal at the beginning warms people of what’s coming.
Isn’t the side port smaller than the main port? It is on a K5 manifold.
If that fitting is a restriction, it could reduce loudness and add to the ‘tail off’.
5 ft doesn’t seem that long… I usually notice the P3 squeal in videos.
Oh and what size valve?
All ports are 1/2" on the p3. The solenoid is also 1/2". Ill have to listen to some videos to compare I guess.
What I usually notice is more startup squeal than tail off.
http://www.youtube.com/watch?v=KPhHXHXcFU8
http://www.youtube.com/watch?v=wYidD2igoQ4
Just a couple examples. Not really any tail-off
All P horns have a squeal, or a chiff. That is the pressure equalizing in front of and behind the diaphragm. You can minimize this by cleaning out the chambers and using the double diaphragm as seen on Micro Precision Group’s website.
I agree with both the postings above, about cleaning out the chambers. I took mine apart before installing them…they were actual service horns from a train out west, and had been sitting in a garage for quite some time. If I remember correctly, the rubber seals themselves need to be clean and dry, as the diaphragms too. (don’t spray any lubricants, WD40, etc)
I have about identical lengths of hoses, in relation the the valve/tank/horns as you do…and I operate at 150psi on 1/2" line as well…and I get zero squeak, just a nice, loud, deep tone…video in my sig.
I wasn’t aware that it’s called chiff. So thanks guys - it led me to some interesting reading…
Yea just like he said every p horn i had had a little squeal in it ive had many 5’s and 3’s