Viair Automatic Mod (VAM)

Hey, Folks.

I got a Viair 300P because it seemed to be the sweet spot between price and rated CFMs. The CFMs certainly did not disappoint after several uses, but the non-automatic part is slightly problematic, esp when doing air checks on all of the family vehicles.

I found some breadcrumbs for an easy mod using a relay and an air horn compressor pressure switch.

Parts are arriving today. So, this should be good to go this weekend.

From the posts around here, I know there are a ton of folks with Viairs. This might be handy?

https://www.tacomaworld.com/threads...ild-and-bs-thread.636594/page-4#post-23970721


Another Viair mod:

The male outlet bothers me. I like female couplers on the tool end. The problem is that the Viair coupler uses straight threads that appear to be M14x1.0. That is the top fitting in the pic below. The bottom one is a standard NPT fitting.


If folks go this route, you should check first. The Viair folks said that the thread was 1/4 NPT and was changed to M14x1.0.

I just found this adapter to try out:
https://www.fittings.space/gbm22-04zf-m14x10mc


It twerkes!

 

Viair Automatic Mod (VAM)

Here's the mod details:

The Viair uses metric fasteners. Nice!

The wiring appears to be 12 AWG. I was able to get it into the 14 - 16 blue terminals.

Schematic:
Apologies for the D- handwriting. See the Upskirt pic below for the matching harness numbers.


Here's the mechanical side:

I reamed the tee fitting, linked below, from 1/8in dia to 3/16in dia since it is not used just for sensing, but for flow also.

Reamed Tee:


Ready to go:



I just enjoy making wire clamps. Of course oetiker or worm drive would be just as good.


General layout:


I drilled a few holes in the foot plate for zip ties:



I used a slightly longer screw and a washer to mount the relay.


The electrical side:

I can choose to use the pressure switch when doing airchecks, or use it in non-automatic mode if I need to.

Deployed:


Stored:



Upskirt:
After this pic, I hit the terminal ends with heat to shrink these killer marine terminals.



Lemme know if you got any questions or comments.



Source info:

Here's what I am working with for the automatic switch:
http://www.rpod-owners.com/forum_posts.asp?TID=7865

I found a ton of switches on Amazon including a Viair version:

$13 Air Pressure Switch 90-120 PSI 1/8"-27 NPT DC 24V 12V Air Compressor 90 PSI

https://www.amazon.com/Pressure-Switch-90-120-Compressor-120PSI/dp/B07XZ1FKYN

$31 VIAIR 90111 Pressure Switch with Relay, Black, 7.3 x 3.5 x 2.3"es

https://www.amazon.com/VIAIR-90111-Pressure-Switch-Relay/dp/B000FQ793A

Pressure switch tee fitting:

$15 GlowShift 3/16” MAP Line Boost T-Fitting Adapter Compatible with Ford F-Series 1992-1997 & F-250 F-350 Super Duty 7.3L 6.0L Power Stroke 1999-2007 - 1/8-27 NPT Sensor Port - Includes Hose Clamps

https://www.amazon.com/gp/product/B00EOT94QO

Pics from the Rpod link:

 

Nice. Will be following closely as I have the same compressor

 

Thanks!

I will take some pics in the middle for this one, not just at the end.

 

I'm curious to see how this turns out too. I went with the slightly smaller, cheaper

$105 Viair 88p Portable Compressor Kit (12V, 120 Psi, Forup to 33" Tires)

Viair 88p (don't air down that often), but I'm guessing that your mod could be modded...

 

Yessir. It will be the same for all Viairs or other 12v pumps that can hit 120psi quickly.

 

The parts came. The existing guts were slightly different than expected, so I am planning this out. They soldered the spade terminals to the switch. I am not going to undo that good connection.

The tee for the pressure switch only had 1/8in dia holes in the barbed ends. I reamed thouse out to 3/16in.

I also tried to swap the male outlet hose connection on the pump to a more typical female connector. Unfortunately, the stock fitting is fine pitch, straight threads. Not 1/4 NPT. Interesting.


Reamed Tee:


Ready to go:


It looks like an external only mod:

 

It works!



I'll post up more pics, details, and a schematic.

 

You are a crafty fella!

 

Thanks, @Shellshock !

The angry pixies didn't get me.

 

@dilbert

Those crimpers that you recommended were top notch. They were a joy to use after only frustration or hand soldering terminals in the past.

 

The ratcheting ones? I love those things, they make a really solid connection.

 

Yessir. I finally bought the ones that you recommended.

The marine heat shrinks were kicking also.

 

Awesome! Between replacing broken sprinkler valves and now replacing damaged underlayment, the flooring, and a toilet in the kids bathroom - I haven't had much time for fun projects.

 

Not good.

I've been putting off shower repair for way too long. We also need to get on some not fun painting.

I'll take the Taco projects.

 

Since you don’t have a tank, I’m having a hard time understanding what the pressure switch is for. I don’t think placed their it’ll give you an accurate (Or even close) reading of tire pressure until the compressor is off.

 

I love that wire hose clamp tool. The connections look so nice. It's on the top of my Amazon wishlist. Then I need to do this mod.

 

It turns it on and off automatically when you connect and disconnect from the tires.

 

It takes longer and is more complicated, but I just enjoy it. The simple, low profile clamps from anything just get me going.

 

Accurate readings and not racing between the pump and the 14 tires that we have for regular checks.

Note that I am using @Shellshock 's deflator / inflator with a digital gauge. The one that came with the 300P is not at nice for a few reasons.