So I know some of you on this forum run 5/8 instead of 1/2 air line. Currently i have all 1/2, and is it worth the effort to take out the 1/2 line and run a 5/8 to my k3’s. but what i really want to know… will the 5/8 make any noticeable difference?
When i bought my k3 i ordered all 1/2" OD, PTC fittings and line…
Installed it all, and was extremely disapointed.
Heres a video of 1/2" line.
It sounds extremely restrictive…
Heres the same horns but just switched to 5/8" OD line and of course all the fittings…
I have to get a out of truck video yet…
Trains run there horns with 1/2" pipe… which is 1/2" ID… All the air lines we use are OD… So if u use 1/2" its only 3/8" or so ID… 5/8" OD will get you the closest sound to the real thing. Some people oven go larger line…
But most important , remember that your line can be 3" diameter!! But it will only supply you the air of your fittings. Meaning yo will wnd up with a bottle neck of restriction if you step down from 5/8" to 3/8 … etc…
It really depends on the size of your fittings. Anything smaller than 5/8" will be the resricting factor.
I did 5/8" i.d. hose on my first setup. I haven’t heard mine with another size airline yet. But the K5 sure ate 9 gallons quick with that big hose.
I went with the bigger hose because the barb fittings are the restriction. I don’t think PTC fittings eat up as much of the tube i.d.
ok ok… interesting.
so if i want to run 5/8 i have to not only change out the fittings, which is understandable, but what about my 1/2 electric valve and 1/2 regulator…
The orifice of my 1/2 valve (15mm I think) was still bigger than the I.D. of my 5/8" barbs @ .465").
The regulator needs to be high flow. Do you have any specs on yours?
well i got it off amazon
see for your self
That should be 1/2" NPT. or in other words 1/2" ID.
Take a 1/2" steel pipe and see if it fits. 1/2" steel pipe is bigger on outside
well easier said than done. i would have to do a lot just to test fit that pipe. But i can tell you that i used the 1/2 npt fittings from home depot.
Specs look good - 1/2", 125 CFM, 250psi Max.
Good price too.
Silvy - not sure if you were referring to my 1/2" valve comment or his 1/2" regulator, but yes I meant 1/2" NPT and the orifice is 15mm.
Funny thing about my regulator - I looked at buying the 3/4" but it has the same exact specs as the 1/2". The size desigantion is only the NPT ports in the body.
so were can i get some reasonably priced 20ft of 5/8 line.
It’s pricey and so are the fittings. McMaster has it, but no 5/8" PTC fittings. PM me for another source.
I was reading some specs on DOT tubing and the wall thickness goes up when going from 1/2" to 5/8". The 5/8" x .092" wall ends up at .441" i.d…
ok ill take a look and see what they have.
BTW what do you guys think of the sharkbite fittings…
i currently have the 3/8 fittings for the 1/2 air line. there easy to get at local stores so if i go 5/8, ill be getting a the next size bigger to fit the line but will it supply sufficient air flow.
Flow should be fine if they fit & hold with your tubing. I have no idea how their sizing works since they say you can use PVC, copper, or PEX - which are sized differently. But hey if you can find the right size, they’re rated for 200 degrees and 200 psi max.
I checked with horn blasters first but they did not have 5/8"
I’ll have to see what i have left. I either bought 25 or 50 ft. when i ordered. I know i have some left but not sure how much…
One tip. Do not get the 5/8" swivel fittings . Because of the swivel , the ID is reduced by a 1/8" or so. Dosent sound like much , but when your going for volume , not having restriction (bottle neck) is the key!
I ordered and installed the swivel at first in the cab and in the bed and ended up ordering non swivel a couple months after and it made a difference. 
[QUOTE=06z71silvy;61965]I got all mine from here…
I checked with horn blasters first but they did not have 5/8"
I used the same source.
Doug is a great guy and will help with whatever you need…
^^ Thanks - I can never remember that source. I’m going to need it at some point.
Yea they were great… I remember I ordered and there was some discrepancy with the line being out of stock but arriving in a day or 2… And they ended up refunding my quicker shipping option and still shipping it the fast way when they got it in.
Honestly tho, if i were to do it again i might even consider going with 3/4". Only drawback would be the bung holes on most tanks are 1/2"…
The main reason is the fittings. They always reduce down and allow restriction. With 3/4" it would reduce down to what you are going for…
Same here - I would do 3/4 if going the DOT route. The i.d. is .566" because of the .092" wall thickness. The i.d. of 1/2" sch 40 pipe is .622" so the fitting might not be too bad for a 1/2" port.
would running 3/4 require upping the size of ALL the fittings to 3/4