Grimm Offroad Mount + ARB Twin Compressor Underhood Install -- DIY Video

[Steed76]

The outside air is typically made up of 78% nitrogen, so just fill up your tires as normal, but then take out about 20% of the air and you should be left with just nitrogen in your tires. Oxygen is heavier than nitrogen, so position your valve stem at the bottom of the tire to more effectively drain the non-nitrogen parts.

Dang! I've been doing it wrong all these years!!!

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[H0pelessOpus]

That Nitro membrane @Tex posted up might be your hot ticket.... Report back with your findings.

If you're serious about the Nitrogen fill, maybe take a look at a Power Tank set-up and get the local gas shop to fill the tank with N.



As far as the compressor itself, they don't care what position they are ran in.

For Grimm, they were trying to stack the compressor in as tight as they could to save room for other under the hood stuff that we all like to jam in there.

Plus, as @toughtoaster mentioned, it makes servicing the air filters really easy.

Is there any concern with mounting the PCM that close to the compressor with all the excess heat?

 

[Tex]

Is there any concern with mounting the PCM that close to the compressor with all the excess heat?

I wouldn't be worried about the heat, an ARB puts out less heat than the radiators and engine, plus when you're using it chances are you'll be stationary with the hood open, and all that heat from the ARB will rise up and away as opposed to rearward in the PCM's direction. I do worry a bit about the vibration being so close and sharing mounting points with it though.

 

[robepa]

I have this kit and like it, one thing to note is the placement does interfere with hood struts if you have those as well. It was easily solvable by remote mounting the filers for the compressor.

 

[Northridge4x4]

Is there any concern with mounting the PCM that close to the compressor with all the excess heat?

I wouldn't be worried about the heat, an ARB puts out less heat than the radiators and engine, plus when you're using it chances are you'll be stationary with the hood open, and all that heat from the ARB will rise up and away as opposed to rearward in the PCM's direction. I do worry a bit about the vibration being so close and sharing mounting points with it though.

What @Tex said^^^^

Plus, the bracket spaces the PCM away from the compressor with a small air gap and the ARB Twin does have a fan in it that will blow the hot air up and out.

 

[GeorgeFromDallas]

I have this kit and like it, one thing to note is the placement does interfere with hood struts if you have those as well. It was easily solvable by remote mounting the filers for the compressor.

What type of hood struts are you running? Do you think any of the other types would be ok?

For reference, I made a post with pic's about potential fitment issues:

https://www.bronco6g.com/forum/thre...d-shocks-cold-air-intakes-kr-jcr-grimm.71885/

 

[Squatch]

This is a sweet looking setup. I'm just on the fence between under-hood and behind the spare.

This looks like a good product, but my dealer filled my tires with pure Nitrogen(tm), are you guys working on a compressor that only compresses nitrogen?

Can you get me one that compresses nitrous right into the cabin? Miles of smiles.

I've been told I'm empty inside, now it all makes sense

No, you're filled with nitrogen... I believe.

 

[robepa]

What type of hood struts are you running? Do you think any of the other types would be ok?

For reference, I made a post with pic's about potential fitment issues:

https://www.bronco6g.com/forum/thre...d-shocks-cold-air-intakes-kr-jcr-grimm.71885/

Options 1 & 2 in your link should work fine, as long as the struts go back to the firewall side instead of foreword from the hood connection point they should be fine.

 

[Chritaka]

I just got this kit! I want to install with the ARB switch under the hood, but ALSO use an upfitter to turn it on. Can I simply use the purple wire from the ARB harness to T into the purple wire on the switch to trigger? This way I can turn on by either the under hood ARB switch or with the upfitter?

 

[Northridge4x4]

I just got this kit! I want to install with the ARB switch under the hood, but ALSO use an upfitter to turn it on. Can I simply use the purple wire from the ARB harness to T into the purple wire on the switch to trigger? This way I can turn on by either the under hood ARB switch or with the upfitter?

Doing it that way, you could have the problem of back feeding power into the up fitter switch, we're not sure what that would do.

 

[Aman]

I just got this kit! I want to install with the ARB switch under the hood, but ALSO use an upfitter to turn it on. Can I simply use the purple wire from the ARB harness to T into the purple wire on the switch to trigger? This way I can turn on by either the under hood ARB switch or with the upfitter?

Out of curiosity, what are you trying to accomplish by utilizing multiple switches? I originally had mine wired to an upfitter switch but ended up rewiring it to use the ARB switch under the hood. It was inconvenient to hop in and out of the cab to power up/down the compressor when everything else was under the hood.

 

[Chritaka]

Out of curiosity, what are you trying to accomplish by utilizing multiple switches? I originally had mine wired to an upfitter switch but ended up rewiring it to use the ARB switch under the hood. It was inconvenient to hop in and out of the cab to power up/down the compressor when everything else was under the hood.

I want the master switch to be the upfitter, so I can't turn on the compressor without the engine running (no need anyway as it'll zap the battery). Then simply use the under hood switch as a circuit breaker. I could leave that on normally so the circuit is complete and turn on/off via the upfitter, but then if I need to I could turn off the compressor via the switch under the hood.

I think I can do this by running a wire from the upfitter to the 20A/10A middle connection on the hood switch, replacing the red wire in the middle in the pic, so it only gets power when the upfitter is on. The 12v connection/purple wire coming out of the hood switch would remain the trigger.

Does that make sense or am I completely off? I found a link here where a guy did this, but he's not responding... This is what he mentioned, but didn't show how it was wired:

-----------------
Here is how I wired my ARB pump.

1. The Aux switch is used as a signal or trigger switch that enables the ARB switch next to the pump. ( This requires I think 8 amps from ARB,
Therefore any of the 10 amp Aux switch’s will work).
Note: **** the main 30/50 amps to drive the pumps is coming from two large amp fuses via the Battery included with the ARB wiring harness)

Also… it lights up the ARB switch to let you know it is “enabled” (see pic).

Why????
It is paramount that you have the engine running when you start up your ARB pump….
This will save your battery…the Aux switch ONLY works with the engine running.
Using the Aux this way acts as a Safeguard against accidentally turning on your pump without the engine running…(which is easy to do)

2… the pump is wired directly to the battery via a relay that comes with the switch.

3… the ARB switch controls the pump
(Wired plug and play as per the ARB directions).


Also… I originally ran with the air outlet on the pump located at an angle (as everyone does in the videos) and discovered that my roof insulation felt was hitting the valve….(not cool!!!)

**** (side note) Not that you need to… but I relocated my outlet valve and switch…. I purchased the switch mount bracket kit from the makers of the pump bracket… now nothing comes close to my hood insulation…
-----------------

 

[Draughon]

Potentially stupid question, but..

Would ANY twin compressor work with this mount? Or does ARB have some specific mounting points?

(Thinking Thor's Lightning, Morrflate, etc..)

Get yours here: https://northridge4x4.com/part/exte...pkg-grimm-offroad-mount-w-arb-twin-compressor

 

[Chritaka]

Potentially stupid question, but..

Would ANY twin compressor work with this mount? Or does ARB have some specific mounting points?

(Thinking Thor's Lightning, Morrflate, etc..)

The ones you mentioned like Thor and Morrflate are a completely different form factor using the Chinese Maxi trac/ NAPA type compressors. They won’t work in this Grimm cage, only the twin ARB or similar knockoffs (likely).

 

[Aman]

I want the master switch to be the upfitter, so I can't turn on the compressor without the engine running (no need anyway as it'll zap the battery). Then simply use the under hood switch as a circuit breaker. I could leave that on normally so the circuit is complete and turn on/off via the upfitter, but then if I need to I could turn off the compressor via the switch under the hood.

I think I can do this by running a wire from the upfitter to the 20A/10A middle connection on the hood switch, replacing the red wire in the middle in the pic, so it only gets power when the upfitter is on. The 12v connection/purple wire coming out of the hood switch would remain the trigger.

Does that make sense or am I completely off?

I understand the advantage of the using the upfitter which will only power the compressor with the ignition on, however I'm not understanding the purpose of being able to turn off the compressor under the hood. Regardless, the way you want to wire it should work just fine.

The only thing I would suggest is always leaving the upfitter in the on position and using the ARB switch to complete the circuit. That gives you the advantage of only powering the compressor when the ignition is on while still giving you the convenience of the under hood switch.

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