Kobalt only has 1 CO2 regulator that I know of... it comes on a belt clip with a quick disconnect so you can wear the tank on your hip and drive nails with an air nailer without being teathered to an air compressor. It's adjustable between 20-125 psi, perfect for a horn setup.

You hit the nail on the head with paintball regulators. They are aimed at much higher pressures than a horn would need. I found one that said that it would dial down to 100 psi, but you had to rebuild the internals and after that it was still fluctuating wildly between 100 and 200psi and leaked badly because it was originally designed for higher pressures and there just wasn't enough force from the lower pressures to ensure a good, tight seal. I was at an impasse for 6-8 months until I was looking for a tool at Lowes and stumbled across the Kobalt unit. When I saw the pressures that it ran at, I knew that the MINI horn was going to happen!

Yes, as any liquid converts to a gas it will cool (how most modern AC units work). If you have too much being vented, it can freeze up a nozel or hose. Because the horn uses the CO2 in short bursts, it isn't a factor for me. If it's an issue for longer use applications (maybe a fog horn?) the 9oz tank isn't gonna cut it anyway. You could lengthen the low pressure supply line (from the valve to the horn) to act as an expansion chamber / heat exchanger and make sure that all of the liquid is gas before it hits the horn.

Here's a picture (from www.lowes.com) of the regulator at a 9oz paintball CO2 canister ($85). It is mounted inside of the black box on the right hand side of the photos... you can see the brass quick connect fitting sticking outside of the box through a tall u-shaped channel I cut to fit.



See the brass quick connect... look for the bit of red tape that is around the fitting that connects the line to the valve to the regulator...

 

Thanks for all of the information on your setup. I've been looking at different ways of doing this myself for a couple of weeks and your setup is very close to what I would want to do.

Two last questions for you. First, is there a particular reason you went with a mechanical solenoid rather than an electric one? I'm hoping to use one of the unused buttons on my steering wheel to activate the horns, but that will require an electric solenoid. I wasn't sure if you chose to go mechanical for a specific reason or if it was just the easiest/cheapest way to do it.

Secondly, the horns you got off of eBay, do you know what brand/model they are? The biggest challenge for me thus far has been finding space in my MINI for horns that sound the way I want. (I haven't replaced my exhaust system as you have). I'm looking for a sound that's deep, but still fits somewhere.

I've looked at JcWhitney, Wolo, Fiamm and several other suppliers to find a set of horns that sound the way I'd like and most of the acceptable ones have been between 14 and 18 inches in length. That said, I don't think I've seen the ones you have on your MINI. I'd love to look at another manufacturer of horns if possible.

Thanks again and great job on both the execution and write-up.

 

Aaron - that's awesome. You da man!

There's few things more satisfying in life than having a REALLY loud horn when the situation calls for it. Just as long as it doesn't get abused.

Reminds me of when I got (OK, but much less powerful) air horns installed on my Mustang. I used to live in Georgetown, and the pedestrians down there were so belligerent that they'd often ignore the fact the light was changing and cross on red anyway. So maddening, when you've already been waiting several minutes at the light, you have a green light to go, and you have to wait for these idiots to get out of the crosswalk.

I have to say, blaring at them with my air horns was very satisfying indeed. I loved watching people literally jump! However, I only did it to people that truly deserved it.

 

Man, you're making me want it even more With all the bad drivers/cyclists/pedestrians around here though I'd probably abuse it and go deaf

 

Just want to add that another option are Palmer's Persuit regulators. They are often used on Classic Airsoft guns which dont require operating pressures much over 80psi. Depending on which you get you have a range of 0-300psi all the way up to 0-800 PSI. There rock regulators (0-300) are cheap too.

 

I bought the horns from a supplier that has several still listed on ebay: http://cgi.ebay.com/ebaymotors/ws/eB...S%252BI%252BSS

I first tried a solenoid when I was rebuilding the original set of military horns, but I couldn't get it to work well with higher pressures above 80psi. I wasn't really happy with the binary setup (on or off) and wanted to be able to have a little more control over the stacato nature of the notes. It probably cost me MORE to use the manual valve because I had to buy and run the t-handle Bowden cable, but I like the look and feel of the final solution and would do it again that way. it was probably the most difficult part of the install, though, as it required some creative trimming inside the center console and dropping the exhaust to run the line.

 

Maybe you can talk MINI USA into offering it as an option so you can put a set on your MINI! :D

 

Thats just plain awesome

 

.... who now has one less set to sell...

But I won't be installing mine until after MOTD... so Aaron's will still be one-of-a-kind this year, probably...

 

Aaron - I'm curious - thoughts on aiming forward vs. rearward? I'm assuming you did this to help keep debris out? I'm wondering if there would be a noticeable difference in volume from the front with one placement vs. the other... given that it's under and behind the car either way, and either way a lot of the sound is going to be reflected off something...

Thoughts?

 

I aimed backwards for several reasons

1. debris collection would be less
2. water intake would be less
3. they fit better that way in the space I had
4. Less stress on the mounting due to air pressure when driving forward

I know that semi trucks mount 'em in a forward facing direction, but their horns aren't 1 foot from the road surface...

Blimey... be sure to stop by and check out the system at MOTD. I'd be happy to show you a few tips on how I set it all up and give you the tour. I think we are both in the car show, so we should have some time...

 

Yep - all those reasons make sense - how much volume difference can you tell, say, 15 feet from the front of the car vs. 15 feet behind?

I'll definitely look at your rig at the MOTD show! Thanks for the offer.

I may start with a solenoid on mine, but eventually want some kind of lever with a similar cable and manual valve... woke up early this morning and laid in bed thinking about what kind of lever and where to put it...

The only concern I have with yours is potential leakage around the quick connect... I have a monster air system in my shop and seems like that's where I often get some air leakage. As you said, not a big deal with a compressor, but more of a concern with the CO2. I suspect you could remove the quick connect and "plumb" the regulator into the system without it, but would be tougher to change bottles.

 

That is so beyond awesome!

 

Yep... I made it 4 days and the bottle is empty. I checked the connections that I made with soapy water and found no leaks, so I think that it's the quick connect as I'm bouncing down the road.

I'll probably disassemble the regulator this weekend to see if I can hard-plumb it.

 

I got my horn today and, of course, couldn't wait until tomorrow to hear it... So I plumbed it up to my shop air supply and rigged a 12 volt power supply to it that I had and OMG!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

This thing is FREAKING LOUD. I put my sound pressure meter a few feet away and measured 126DB. And that's only running it at about 20psi!!!! And I'm not sure I used the meter right, because it hurt a lot more like 140-150db...

The solenoid that came with it won't open above about 20psi... and I'm pretty sure I did a Pete Townshend on my hearing in the 10 minutes I was playing with it inside my shop.....ears are ringing now, 30 minutes later...
And the family dog now HATES me. And he was on the other side of the house.

It was really freakin loud at ANY pressure I tried - but there was definitely a difference between 10psi and 15psi and 20psi - I can't imagine the head-splitting vibe Aaron's producing at 80-100psi...

So, anyway, now I have to decide if I'm going to use the included solenoid and stick with the lower pressure (at least for my initial quick and dirty install) or if I'm going to seek out a higher-pressure solenoid, or if I'm going to go all out the first time around and use the cable and manual lever rig...

Decisions, decisions...

 

So, good news... I sent a message to the seller and they confirmed that I must have a bad solenoid, so they're sending me a replacement on Monday. So looks like maybe if I have time this weekend I'll start THINKING about the install, what I need to fab, etc.

I ordered the MFSW phone button relay splice kit from Mikey at newministuff.com, and plan to use the phone button as my trigger for the solenoid. Not as cool as Aaron's t-handle and cable rig. On purpose. Don't want to steal ALL his thunder. Might still fall back to a lever-driven "analog" valve in the future, if I get bored...

I think I'll put a red vinyl decal on my phone button so it just BEGS clueless people to press it. Though I guess I'd better put those clear plastic sofa covers on my leather seats first.

 

Awesome job Aaron

 

So I'm walking through the parking lot at the mall today (minutes after buying my Kobalt regulator and two 20oz tanks), and what do I see?


Hmmm... what's under there?





Similar four-horn set - just bigger. And not concealed nearly as well. Note the compressor and air tank in the upper left corner.

 

On a car that big they couldn't find a better place than that? Ha!

 

I made a run to a sporting goods store to fill up the CO2 cartriges and decided to do some exploring tonight, so I took the regulator and my tools inside to crack the case open. I was standing right over the sink when I got it open, so I decided why not... Leak test! I filled the kitchen sink up with water and put the whole thing inside. There was a little set screw that was leaking CO2! A small, but steady stream of bubbles! One quick twist with an allen key and it was all taken care of. (Cabrio: a small, dark colored allen-head set screw on the main component in the regulator on the side opposite of the pressure set **** - I'd be interested to know if yours leaks as well and if the leak is designed in to the system for some reason)

I cranked the pressure up from 80psi to 120 and re-installed everything with a fresh tank of CO2. I'll let you know how long I make it. I left the quick-connect in place for now, but it should be fairly easy to remove from the system if I decide to do so. It makes install a bit easier w/ the quick connect, so I'll give it a shot for now.

 

That's rad!

 

Thanks for the update, Aaron - I'll check that screw, too. I bought two 20oz tanks - they have slightly different threaded fittings on them and one will not go on without venting lots of CO2 - even with a new o-ring. So I gotta take that one back and exchange. Got my replacement solenoid but haven't tested it yet. Have a trip this weekend, and am waiting on my relay trigger from England before I do the install... but I'm gettin' antsy.

 

Blimey, where are you planning to hide the horns? Are you missing a muffler like the OP?

Ivan

 

I did my first blast of the horns at 120 psi this morning. From the driver's seat, I like the tone of the horns at 80psi more. I'll have to find a quiet (well... secluded) place to blast some test shots this afternoon.

The regulator case was simple to crack open... 2 Phillips head screws near the attachment point to the tank and 4 metric-sized allen head screws that are under the belt clip and it all comes apart.

 

Yep - I have the one-ball exhaust mod... so my rig will be in the same place, except on the passenger side. I may position things a little differently and won't use the box for the cylinder (have something else in mind) and may mount it differently - but same general concept. I'll have more flexibility in positioning since I'm going to use the solenoid to fire it - not constrained by the cable run (though Aaron's cable rig will FOREVER RULE ).