Under Bonnet ARB Compressor

[mrapocalypse]

The second battery under my bonnet has been dead for ages.

It was badly affected by the heat.

https://www.aulro.com/afvb/images/imported/2015/03/306.jpg (http://s518.photobucket.com/user/NomadCamera/media/010SecondBatteryandInnerTube.jpg.html)

I thought the ARB battery cradle might be good for the ARB Compressor. For tyres not diff locks sadly.

Are they OK in the heat from the engine?

I figure I might have to build a more substantial heat shield for it but they seem to be OK under there.

Mine's a V8.

[AndrewMilne]

I thought the ARB battery cradle might be good for the ARB Compressor. For tyres not diff locks sadly.

Are they OK in the heat from the engine?


I don't think that under the bonnet is a good place for a compressor, and especially not near the exhaust manifold/s, exhaust down-pipe, or turbo.
When you run a compressor, it gets hot, and so does the air that has been compressed. This heat has to be disposed of by the compressor (which is why it has cooling fins).
Under the bonnet, the intake air for the compressor is already going to be heated (and hence somewhat expanded).
So then the compressor is trying to compress warm air that has been expanded prior to entering it.
AND the compressor has to dispose of extra heat after compressing the warm air.
AND the compressor has to transfer heat to already hot surroundings!
Inefficient and hard on the compressor.
AndrewMilne

[BKH]

Don't do it.
Everything AndrewMilne said is true. I have a TJM big red 2 under the bonnet and it dose not work as well as my portable unit in the box (which is also the TJM big red) after the engine has heated up.
Once the heat builds up in the engine bay I go to inflate the tyres and after a minute or two it would cut out. I took it back to TJM and they informed me that it was tripping due to the heat. The unit works well when cold but only has the issue after a run in the car. The one I carry in the box in the back of the car has never had this issue.
Regards
BKH

[mrapocalypse]

Thanks guys.

Glad I asked.

Ian.

[XDrive]

I have an ARB compressor mounted in the engine bay and this is used to run both Air Lockers and as a compressor for pumping tyres.

I have never had an issue with this unit. If I wish to inflate tyres, the bonnet is up and any hot air has an escape route. The unit is high up and therefore has access to air being drawn in from the outside via the open bonnet. Whilst using the unit to engage lockers, it only runs for a few seconds each time. I do not have it connected to an external air tank, using only the air stored in the units own tank.

Just commenting on my experience, others here, have different experiences.

Regards

XDrive

[rangieman]

I have an ARB compressor mounted in the engine bay and this is used to run both Air Lockers and as a compressor for pumping tyres.

I have never had an issue with this unit. If I wish to inflate tyres, the bonnet is up and any hot air has an escape route. The unit is high up and therefore has access to air being drawn in from the outside via the open bonnet. Whilst using the unit to engage lockers, it only runs for a few seconds each time. I do not have it connected to an external air tank, using only the air stored in the units own tank.

Just commenting on my experience, others here, have different experiences.

Regards

XDrive

x2 Yep same experience here :BigThumb:, Oh i have just replaced the compressor as i had the large old style compressor that blew up yes blew the cyclinder off the compressor motor still worked fine ,
Make your own mind up or follow the crowd:confused:
2xfor
2xAgainst

[mrapocalypse]

x2 Yep same experience here :BigThumb:, Oh i have just replaced the compressor as i had the large old style compressor that blew up yes blew the cyclinder off the compressor motor still worked fine ,
Make your own mind up or follow the crowd:confused:
2xfor
2xAgainst

So if i follow your advice is that making my own mind up or following the crowd?:p

It's an expensive experiment. Which is why I suppose one asks advice.

So performance is affected but it's not bad for the compressor?

And I take the point about bonnet being open during operation which would take most f the heat away. So Maybe..... ???.

[rstevensen]

As an alternative, my arb compressor is behind the driver-side headlight as there is enough of a gap to have it there.

[Fast Freddie]

A careful analysis of the available data would seem to suggest that :

Putting it under the bonnet is a great idea, because "I've done that".
The head will come off the compressor though.

[Tombie]

Always had compressors under bonnet (ARB units) and never had a worry..

Now though - not needing lockers - I keep my compressors portable, they have a lot more versatility that way..

In a D2 put the compressor in behind the panel as you look inside the tailgate (behind that vent)... Work great in there and out the way.

[onebob]

I don't think that under the bonnet is a good place for a compressor, and especially not near the exhaust manifold/s, exhaust down-pipe, or turbo.
When you run a compressor, it gets hot, and so does the air that has been compressed. This heat has to be disposed of by the compressor (which is why it has cooling fins).
Under the bonnet, the intake air for the compressor is already going to be heated (and hence somewhat expanded).
So then the compressor is trying to compress warm air that has been expanded prior to entering it.
AND the compressor has to dispose of extra heat after compressing the warm air.
AND the compressor has to transfer heat to already hot surroundings!
Inefficient and hard on the compressor.
AndrewMilne

..... I have an ARB compressor installed on an ARB dual battery tray and my solution to the underlined above was to remove the disc filter, and fabricate and attach a snorkle pipe in its place. The snorkle pipe passes through the fire wall and then up to near the bottom of the A pillar beside the glove box. The disc filter is attached on the end of the snorkle pipe. The compressor only draws clean conditioned air from the cabin.

onebob

[mrapocalypse]

..... I have an ARB compressor installed on an ARB dual battery tray and my solution to the underlined above was to remove the disc filter, and fabricate and attach a snorkle pipe in its place. The snorkle pipe passes through the fire wall and then up to near the bottom of the A pillar beside the glove box. The disc filter is attached on the end of the snorkle pipe. The compressor only draws clean conditioned air from the cabin.

onebob

I Likee.

Also in the back bit of the load area. That works for me too.

I.

[rangieman]

A careful analysis of the available data would seem to suggest that :

Putting it under the bonnet is a great idea, because "I've done that".
The head will come off the compressor though.


Ill clarify :censored: It blew the air cylinder off the compressor not the head. Could be that i have a 19 ltr air tank plumbed straight into the compressor so the ARB boffins:wallbash: tell me :angel:

[Fast Freddie]

Ill clarify :censored: It blew the air cylinder off the compressor not the head. Could be that i have a 19 ltr air tank plumbed straight into the compressor so the ARB boffins:wallbash: tell me :angel:
Sorry about that, I didn't mean to appear rude.

Some good suggestions and alternatives appearing in this thread though. Chilled air from the cabin or stowing the compressor in the rear panel sound great.

[onebob]

..... I have an ARB compressor installed on an ARB dual battery tray and my solution to the underlined above was to remove the disc filter, and fabricate and attach a snorkle pipe in its place. The snorkle pipe passes through the fire wall and then up to near the bottom of the A pillar beside the glove box. The disc filter is attached on the end of the snorkle pipe. The compressor only draws clean conditioned air from the cabin.

onebob

My ARB onboard compressor is the "littlun" that's recommended for air lockers. However I don't have airlockers but use it for my air ram Center Diff Lock actuator. The compressor has a pressure switch and only comes on for short bursts every 20 minutes or so. Other than that it's also used for "airing up" the tyres at the end of the expedition and for that the engine need not be running, the engine compartment lid is open and so no stress on the "littlun" = happy days.

onebob

[Mundy]

I have had an ARB compressor under the bonnet on an ARB battery tray for a couple of years without problem. However due to my concern over the heat of the compressor from the turbo, I built a box around it, with a 80mm computer fan, blowing in air ducted from the front of the engine compartment. Works a treat, even if it looks weird.

You can see the pictures and description on my post dated 14 May 2014 titled Wierd Project #2. Link is: http://www.aulro.com/afvb/discovery-2/197622-weird-project-2-compressor-cooling-box.html.

[zzsteve]

ARB compressor under bonnet with V8 here
http://www.aulro.com/afvb/projects-tutorials/117167-arb-replacement-wabco-sls-compressor.html
Coming up 5 years with no problem. It runs my SLS every day
Steve

[Toxic_Avenger]

First choice for me would be inside the vehicle (cool and dry)
Second choice would be in the engine bay with air pick-up point somewhere cool and dry.
My last choice would be in the engine bay with the filters sucking hot air.

Heat soak into the unit from the engine alone would see the unit getting to some respectable temps before you even begin to compress air. Then you will start to see even higher temps.

[mrapocalypse]

..... I have an ARB compressor installed on an ARB dual battery tray and my solution to the underlined above was to remove the disc filter, and fabricate and attach a snorkle pipe in its place. The snorkle pipe passes through the fire wall and then up to near the bottom of the A pillar beside the glove box. The disc filter is attached on the end of the snorkle pipe. The compressor only draws clean conditioned air from the cabin.

onebob

Would you mind posting a few pics of your snorkel set up for those playing at home please.

Sounds like the go to me perhaps with a heat shield around it too for me.

I

[onebob]

Would you mind posting a few pics of your snorkel set up for those playing at home please.

Sounds like the go to me perhaps with a heat shield around it too for me.

I

certainly!...... I been away 4 days solo camping at Woods Point BEFORE the Easter Rush arrives and just got back home so log back-in in a day or two and I'll have some pics up.

onebob

[onebob]

Okay... mrapocolypse here's a pic of the type of compressor I have and another of it installed.

If you look closely in the installation pic you can see that the disc filter is removed and 2 green anodised (male to female and male barb from the "red and green shed") fittings installed in its place, then a short piece of black pvc hose to the blue plastic elbow (from an automotive supplier). Another piece of black hose is connected to the elbow travelling back to the firewall passing thru beneath the bonnet pull cable that can be seen on the just visible (painted) firewall. On the inside the black hose passes upto the base of the "A" pillar with a male barb fitted to receive the disc filter.

onebob

https://www.aulro.com/afvb/images/imported/2015/04/1219.jpg (http://s149.photobucket.com/user/onebob_photos/media/compressor_zpsewelkjtz.png.html)


https://www.aulro.com/afvb/images/imported/2015/04/1220.jpg (http://s149.photobucket.com/user/onebob_photos/media/compr.%20snorkle_zpsggagovq3.jpg.html)

[imatt]

I orginally had my ARB high flow compressor mounted in the rear of my disco behind one of the access panel, my wife complained about the noise (it was used for my sls and plumbed to an air tank), so I moved it to the engine bay and mounted it in the battery box where the Jack normally sits, fits well. It worked fine while I owned the car.

[Slunnie]

Ive had the old type and new type ARB compressor under the bonnet now for about 13 years. No probs from its location at all. The lockers pull very little air and for tyres the bonnet is up. The old one dropped its conrod, the new one has been in for about 7-8 years and has never had to be touched other than fitting and connecting/removing the air hose.

[rstevensen]

And here are a couple of photos, notice the air outlet and filter installed remotely in the engine bay and the compressor behind the driver-side headlight.