How-To: DIY Manifolds for Nathan K3 & K5 Airchimes

Having recently upgraded from a set of Shockers to a K3LA I had to build my own manifolds and mounting solution. I just thought I’d share some ideas and files and hope someone finds them useful down the track.

The following contains:

[li]Instructions on how to build a set of custom manifolds in case you don’t have room to mount the Nathan Airchimes on the factory manifold.[/li][/ul]

[li]Blueprints and photos for the manifolds[/li][/ul]
The idea is simply to sandwich steel or alloy plate between the horn manifold and another matching manifold block. The plate material can be a bracket or other suitable piece which is easily mounted.

Here’s a side on illustration of the basic parts and a pic to illustrate and what the end result looked like

Materials needed:

[li]The template for the manifolds (download here)[/li][li]2 pieces of Letter size paper or Sticker sheet.[/li][li]The manifold block material. I used 10mm Delrin (Acetal Resin) but you could use a swag of other similar types including Nylon etc. I found the the Delrin to be a good balance between strength whilst not being too hard to work with.[/li][li]The mounting material which gets sandwiched between horn and the Delrin. I used 4mm Alloy plate, cut into strips.[/li][li]Depending on the thickness of the materials you choose, you may need to get some new bolts. The Nathan K horns use a 3/8" bolt.[/li][li]Quick Fit Elbows with a threaded end. I used 5/16 QF to 1/8" NPT (See footnote for an update/change)[/li][li]3/8" Drill bit[/li][li]11/32" Drill bit if you’re using the suggested elbow size (otherwise adjust to suit)[/li][li]1/8 Thread Tap[/li][li]Set of O-rings (3/4") - Optional, but highly recommended[/li][/ul]


[li]Download the template for the manifolds and print it on an adhesive sheet or paper.[/li][li]Cut out the stencil shapes and glue them to the Delrin as well as the alloy plate.[/li][li]Drill all required holes before cutting the manifold shape. The outside mounting holes which go through from the horn side to the block are 3/8". [/li]
If you’re using the 1/8" NPT elbows, drill a 11/32" hole for the air line fitting and then thread the hole with the tap.

[li]Now cut the outside shape of the stencil. This isn’t really crucial but it will match the same pattern as the horn. [/li]
[li]Note that the Airchimes have an O-ring around the manifold. You can replicate this on the Derlin block as well by using a hole saw or a dremel to cut an O-ring groove. If you’re using the Delrin again, this isn’t absolutely crucial since there is some flex in the material and when the bolts get tightened I found on an early version I got a perfect seal without using O-rings. [/li]
Here’s the finished article ready for mounting:

[li]Mount the alloy strips or brackets, then mount the horn from one side and the Delrin manifold block from the other. Tighten all bolts and hey presto you’re done![/li][/ol]
As I said, nothing fancy, but it works real well and I hope that at least the stencil will come in useful.

[UPDATE] Since making these, I have made some changes to go to a 1/4" NPT swivel to 1/2" push fit. I think it’s definitely worthwhile to run 1/2" line up to the horns to get them enough air unless you’re running very short lengths of 5/16" air line. The restriction right at the throat won’t be a problem since the air intake on the Airchime is much smaller still. Example install:

Sweet - this could really help some people. And people can get a manifold from Mcmaster Carr. Where did you get your blue annodized manifold?

I like the hole saw idea for the o-ring groove.

Looks like the air manifolds I have for extra plugs (mine arrived the same color as his, the website shows lighter)

Awesome job thanks for sharing.

For some weird reason, i cant see any of the pics & none of the links work:(

Sorry for the pics disappearing. Our web-hosting provider is undergoing a server migration. Everything should be back in 24-48 hours apparently.

I got the manifold from a local hose & fitting place called IFS (

Thats sweet! Very clever, you should start selling them?:smiley:

Very nice! This is exactly what I was thinking about doing in my little truck. Thanks for figuring it out for me and putting up nice photos :smiley:

One question: A quick search didn’t turn up a source for 10mm delrin. Any ideas where I might can find a little sheet of the stuff?

Great work! You should definetely post a video of them in operation!

Apparently I didn’t look nearly hard enough. Believe I found something similar right on amazon

3/8" x 6" x 12" $19.86 shipped

Have you hooked yours up and used them? Do those elbows move plenty of air? Thanks again!

McMaster Carr is a great source for your plastic and they also have aluminum manifolds. 1/2" NPT inlet ports and 3/8" NPT oulet ports. (3 port - 5469K115, 5 port - 5469K135) Just plan ahead for your all your fitting sizes, tubing size, and tap size.

Yea that’s the stuff. I figure a standard Nylon type chopping board from a local kitchen supply store would also do the trick.

Horns have been hooked up for a while and are working a charm. You can see a brief video of them on here (

Should note that at the time I was running four horns (the K3 + 1 XL). When I redid the manifolds I ended up taking the XL horn out. If anything it’s made the setup even louder since all the air is going via the Nathans now.

Last weekend I also built in a Viair 400c and 5 gallon tank to swap out the 2 gallon setup I had from the Shockers.

Those elbows flow plenty of air - nor worries about that. The smallest aperture isn’t in any air fitting anyway - it’s in the base of the horn itself. The final port inside the horn is like a toothpick.

A cutting board was actually one of the first things that came to my mind.

Thanks much for posting this information!

Before viewing this, my original plan was to install my old Shockers onto my 2000 Honda Accord. Looks like My Honda is getting some Nathans also :slight_smile: Might do this with a K5.