CTIS retrofit

[BrainP]

Has anyone removed the CTIS controler and made their own system? I did a search and could not find anything that sounded like what I am thinking of. I would think with a few valves, gauges and regulators you could get rid of the CTIS ECM. Any thoughts?

 

[Suprman]

If the feed side air path is working properly the system will usually be working. If you have air leaks from the valve body in the cab to one or more of the wheels then even with a retrofitted air feed it will not work. If its not working it can be fixed. What are your symptoms?

 

[BrainP]

none, it works fine.

 

[Suprman]

I would leave it alone then. If you don't want it doing the continuous pressure checks just unplug the controller until you want to use it again.

 

[BrainP]

You're missing the point. For my project I need to eliminate as many 24volt systems as I can. I am looking for someone who has converted their CTIS system from an automatic to manual system.

 

[armybrattony]

i understand what you are talking about. want to get rid of all the electronics in the system right?


i know in the TM's there is an air flow diagram... the only safe way that i can think of off hand is to have one valve for each tire, and one gauge for each tire. my first thought was one gauge and one valve. but then if you got one flat, all the tires would drain down.... BAD. maybe some check valves or something but i wouldnt trust that.


i dont know that i would use this exact valve, but something like it....

http://www.grainger.com/Grainger/INGERSOLLRANDARO-Pneumatic-Valve-3NB19?Pid=search


with that you can mount 6 of them on a nice panel with a gauge above each one. push the lever up and it fills the tires, push the lever down and it drains the tires...


let me know what you think. if its something along what you are thinking of i can cad you out a panel so you know what it would look like




thanks
tp

 

[FASTNOVA]

I was thinking the same thing having individual valves and gauges for each wheel.

 

[Suprman]

There is a pressure sensor in the valve body. There are 2 lines one is air in and one is an air feed into the valve body and one is air out from the valve body to the tires. You would want to have a feed in regulated to around 70psi or whatever max pressure you want the tires to fill to. A steady 20psi feed will hold the wheel valves open and allow air to dump so you will need a regulator set to 20psi. In theory this will not let you go lower than 20psi but sometimes when you get that low the quick release valves don't stay closed all the way and you need to manually air up the tires a few psi then you can feed in air thru the system. I think most people that modify the system just schrader it off and manually raise and lower pressure thru the wheel stem with a gladhand hose.

 

[armybrattony]

realisticly that would be the "fail safe" military way of doing things..... kinda surprised that not of the older trucks were before the m939a2 stuff.

 

[Suprman]

At first I though the ctis was cool but unless you routinely go for paved road to rough terrain and back you won't be using it much and the once in a while when you do want to lower tire pressure for off-roading you can just let some air out of each tire thru the valve stem. The air feed to each tire travels thru the hubs. There are 2 seals around the axle that make this possible. These seals go bad over time the military replaces them on a schedule and the seals are available and relatively inexpensive but it's a lot of labor to pull the wheel, brakes and pull out each axle to replace those seals. When any one of the 6 axles is leaking thru the seals your feed side looses pressure and the 65psi going in to fill tires can mimic the 20psi dump feed and tire pressure can go down when you think you are making it rise.

 

[BrainP]

Those are some good ideas, but I think my buddy and I came up with something over a few beers while sitting in the shop and staring at the truck(where my best work is done). Im looking into an airirde controler that has a digital reaadout and allows you to set the airpressure to whatever you want. I will install solenoids that will isolate the tires when the engine/compressor is not running to hopefully minimize the chance of one tire running them all flat. I will also put in a few manual valves in to do the same thing I need be, and a few toggles to do the same thing. Still mapping out the system, but i like where it is headed. The truck is being built to haul our 20k lb toy hauler to the dunes, dessert, and mountains. It probably wont see much more time than that. I would rather hit a button a few minutes before the trail head than sit on the beach and air down 6 large tires. It may sound just as complicated, and before anyone else says just leave it then, keep in mind, Im trying to get specific control over tire pressure and eleiminate 24volt features. I would still love to hear more ideas.

 

[Suprman]

I think your idea will still need 24 volts. The air does not just escape the wheel valve prevents this. A steady 20psi from the fill side holds the wheel valves open so you can dump pressure. You cannot eliminate the wheel valves the rest of the system is not designed to hold tire pressure full time you will blow all the hub seals.

 

[BrainP]

What do I need 24 volts for. All I need to do is mimic what the ctis does. Are the wheel valves electric?

 

[Suprman]

You said your air ride controller has a digital readout and you have solenoids. They will need voltage from somewhere.

 

[BrainP]

They are 12volt

 

[trukhead]

Your idea is destined to failure. Go ahead and waste your time, the beer manufactures thrive in garage engineering. The CTIS is designed for pulsing the system to make it air up and otherwise control the tire pressure. As previously stated the system is not designed to hold a continuous pressure to hold the tires at highway inflation. The seals will likely prematurely wear and then not hold any pressure for any period of time.

 

[BrainP]

I understand how the system works. I know that it is based on pulses. I know that once the desired tire pressure is reached, it is held outside the wheel valve and the system is bled down to 20psi to maintain it. Like I stated earlier, I am looking for a way to mimic the CTIS ECM in a way that i have more direct control. If you want to be rude, go do it somewhere else.

 

[Suprman]

I see what you are doing now. If you want to just run a 12v system there are dc-dc converters that will step up 12v to 24v if you do decide to keep the existing controller And valve body I don't think they take much current. If you are completely eliminating 24v in favor of 12v you will need to get a 12v fuel solenoid too. The pulse thing the system does is a pressure check so the system can determine wether to fill hold or dump. The wheel valve is a rubber seal with a spring.

 

[armybrattony]

If this whole thing revolves around needing to use 12volt..... why not just build a 12v system off the 24volt system....

Thats what we did to use cig lighters and chargers and stuff...

 

[BrainP]

95% of the truck components are going to need 12volts, I have a 12v to 24v converter that is good for 40 continuous amps. That will take care of essential 24 volt systems that cant be converted. This isn't a discussion on 12 vs. 24 volts.