On board air

[hotponyshoes]

The a/c pumps work but output is low. Fine for emergency use but to do anything useful you really need an air tank for storage.
For the space the tank takes up you may as well just run a small electric compressor and an inverter. Or just carry a engine driven compressor around.
Or one of the cordless options if you already have a battery system and can get by with a couple of cfm?

Or you could mount storage tank(s) somewhere out of the way and fill them from the workshop compressor before you leave.

Also, if it's a modern diesel van, leaving the engine tickling over with no load might well give you grief with the egr, dpf, etc. especially if the compressor pulls the revs down. Most raise the rpm a bit when the ac kicks in although if the van was originally available with ac it should be possible to trigger that with a bit of fiddling

 

[James1979]

The a/c pumps work but output is low. Fine for emergency use but to do anything useful you really need an air tank for storage.
For the space the tank takes up you may as well just run a small electric compressor and an inverter. Or just carry a engine driven compressor around.
Or one of the cordless options if you already have a battery system and can get by with a couple of cfm?

I can undersling the tank. There’s no spare wheel due to the spec of the previous owner so it’ll go there. Tanks aren’t an issue to source either for me.

Was looking at the Milwaukee ones. The actual compressor in M18 is what I’d need and that’s a bit spendy at the moment. The reviews don’t seem to think it’ll like tyres. It’s more for Brad nailers. It won’t run a framing nailer, apparently.

The tyre inflators don’t have ‘free air’ ie they’re no good for blowing out filters and I’ve tried one on a tractor front tyre. It did not like it.

Or you could mount storage tank(s) somewhere out of the way and fill them from the workshop compressor before you leave.

It’s a plan. Knowing me I’d get caught short somehow! I just would!!

Also, if it's a modern diesel van, leaving the engine tickling over with no load might well give you grief with the egr, dpf, etc. especially if the compressor pulls the revs down. Most raise the rpm a bit when the ac kicks in although if the van was originally available with ac it should be possible to trigger that with a bit of fiddling

This is the big thing that worries me. Especially after the BMW police car issue which was attributed to idling then driving but I think idling then having its c*** ragged out would be more precise

I’m considering a fast idle mod for it anyway once i can figure out that. Ie either a mechanical hand throttle, or a mod somehow with a switch. The second is the preferred option.

 

[m_c]

The big drawback of belt driven compressors is you can only realistically pull a couple hp through the clutches.

We maintained some tyre fitter vans with that setup and they often burnt out the clutches as they were that borderline for power. If the air pressure went slightly too high, the clutch couldn't handle it and the compressor would just stall, followed by lots of smoke.

Latest vans are running electric compressors from a battery bank, although we don't get involved with them, so I have no idea what the actual setup is.
Drivers can change a full set of car/van tyres without having the van running.

 

[James1979]

The big drawback of belt driven compressors is you can only realistically pull a couple hp through the clutches.

We maintained some tyre fitter vans with that setup and they often burnt out the clutches as they were that borderline for power. If the air pressure went slightly too high, the clutch couldn't handle it and the compressor would just stall, followed by lots of smoke.

Latest vans are running electric compressors from a battery bank, although we don't get involved with them, so I have no idea what the actual setup is.
Drivers can change a full set of car/van tyres without having the van running.

I thought this might be the way long term.

Engine idling here isn’t an issue but it will be one day I suppose.

Other than the tmax which is really spendy now, the other 12v compressors I’ve tried are crap. Could be a 24v one though if it’s off a bank I guess.

 

[James1979]

I was parked next to a Range Rover when the owner got in and started the vehicle. Just took a few seconds for the pump to raise the suspension significantly so assume they are quite powerful and decent flow rate

I was looking at them on eBay and the wires are tiny which doesn’t inspire a great deal of confidence.

I suppose filling up a couple of airbags at start up isn’t a huge draw application :/

 

[hotponyshoes]

If they do need holding in place you can drill one side to crush tube OD, and the other side the bolt hole size. Then cut the tube so it sits flush when pushed in and that way you only need to weld one side.

I did a blueprint to show the details.

View attachment 387477

I can undersling the tank. There’s no spare wheel due to the spec of the previous owner so it’ll go there. Tanks aren’t an issue to source either for me.

Was looking at the Milwaukee ones. The actual compressor in M18 is what I’d need and that’s a bit spendy at the moment. The reviews don’t seem to think it’ll like tyres. It’s more for Brad nailers. It won’t run a framing nailer, apparently.

The tyre inflators don’t have ‘free air’ ie they’re no good for blowing out filters and I’ve tried one on a tractor front tyre. It did not like it.

It’s a plan. Knowing me I’d get caught short somehow! I just would!!


This is the big thing that worries me. Especially after the BMW police car issue which was attributed to idling then driving but I think idling then having its c*** ragged out would be more precise

I’m considering a fast idle mod for it anyway once i can figure out that. Ie either a mechanical hand throttle, or a mod somehow with a switch. The second is the preferred option.

Some of the air brake tanks would be ideal for underslung mounting. If you ran the air lines to a manifold you could tap each tank individually, then you could maybe inflate 4 tyres to 20psi from one tank then top them up to 30psi from the other. Or go from 25 to 30 with a 12v/m18 compressor. Fill them before you leave and carry a small compressor/ac mod to top them up if required. You could only fill one tank if you only needed a bit of air.

Some of the older stuff just split out the trigger wire to the pump clutch and the ecu so would be easy.
Some of the newer stuff is canbus so you might need to use an original ac switch plus fake inputs from the various sensors.
On my vw you can choose what rpm the engine runs at with the ac on which might be good for bigger/multiple pumps.
Fit a high/low pressure switch to control it.
If you have start/stop and can break into that somehow you could even stop the engine when not required.

 

[Shox Dr]

I you might not like this When I built a LR90 I wanted on board Air. I was going to use a RangeRover Air con unit. But then... it was suggested to use a Pub CO2 bottle. Plenty of air(Nitrogen) wont flat your battery takes up little space, and is instant.
Sorted!

 

[hotponyshoes]

The big drawback of belt driven compressors is you can only realistically pull a couple hp through the clutches.

We maintained some tyre fitter vans with that setup and they often burnt out the clutches as they were that borderline for power. If the air pressure went slightly too high, the clutch couldn't handle it and the compressor would just stall, followed by lots of smoke.

Latest vans are running electric compressors from a battery bank, although we don't get involved with them, so I have no idea what the actual setup is.
Drivers can change a full set of car/van tyres without having the van running.

Don't ac compressors make enough pressure without overloading them then?
I had it in my head they ran 200psi+ which should be plenty to fill a tank.
It might take a while to fill it.
I know the ac on my truck kicks on and off so they might have a duty cycle but I'd guess if i lived somewhere hot enough then it would be designed to run continuously?

 

[hotponyshoes]

I was looking at them on eBay and the wires are tiny which doesn’t inspire a great deal of confidence.

I suppose filling up a couple of airbags at start up isn’t a huge draw application :/

It's a 20a fuse for the landrover compressor I think. But it doesn't run continuously, there is a air tank on them as well.

 

[armalites]

There’s no tank on them as far as I know so that’s promising

RRS(early) and D3/D4 certainly have tanks. That's how they get the quick response.

They do have a duty cycle and if everything is working correctly IE no leaks etc then they shouldn't be doing too much work.

You'd probably be better with a Viair unit and a tank. Viair do some 100% duty cycle units

 

[123hotchef]

I converted my AC compressor and made a tank from a gas bottle. Worked great until the pump died, it got a feed from the rocker cover to give it some lubrication.
Would run windy gun no problem.

 

[James1979]

I converted my AC compressor and made a tank from a gas bottle. Worked great until the pump died, it got a feed from the rocker cover to give it some lubrication.
Would run windy gun no problem.

That’s a good thing to know.

Yours was an l200 I think?

 

[123hotchef]

That’s a good thing to know.

Yours was an l200 I think?

it was indeed

 

[owas]

I used a standard disco 300tdi pump and put an inline oiler on I think and then an oil separator after the pump, wired the magnetic clutch to a pressure switch so it always kept the the lorry air tank full.
Never actually needed or used it so I scrapped the lot.

 

[Erie Fred]

I you might not like this When I built a LR90 I wanted on board Air. I was going to use a RangeRover Air con unit. But then... it was suggested to use a Pub CO2 bottle. Plenty of air(Nitrogen) wont flat your battery takes up little space, and is instant.
Sorted!

I have several CO2 bottles, 5lb to 20 lb all gotten free or cheap.

Originally for my MIG welders, but I did set up one regulator with a coily hose and standard air quick coupler. I grab it when needed to fill a tire or run an impact wrench. Works good.

 

[Cobbler]

I have several CO2 bottles, 5lb to 20 lb all gotten free or cheap.

Originally for my MIG welders, but I did set up one regulator with a coily hose and standard air quick coupler. I grab it when needed to fill a tire or run an impact wrench. Works good.

I do that with a 13kg butane cylinder, very useful at times.

 

[hotponyshoes]

Is there a pressure rating on the co2 / propane bottles?
They might be fine but might be worth checking?
Plenty of people seem to use propane bottles for additional compressor tanks though..

 

[Erie Fred]

I do that with a 13kg butane cylinder, very useful at times.

Are you filling it with air ?

 

[anto44]

I wired up a air suspension compressor into a friend's 4x4 to use for pumping tyres, they're not designed to run for very long and will get very hot very quickly. He ended up buying a 12v compressor that I seen someone on here recommended.

 

[mtt.tr]

Don't ac compressors make enough pressure without overloading them then?
I had it in my head they ran 200psi+ which should be plenty to fill a tank.
It might take a while to fill it.
I know the ac on my truck kicks on and off so they might have a duty cycle but I'd guess if i lived somewhere hot enough then it would be designed to run continuously?

I've seen 30bar on a faulty unit.