So in the usual way of offroading being a cover story for acquiring shiny toys...I found enough excuses to buy the recently released ARB brushless compressor. I've been meaning for some time now to replace the wiring that runs power back to my onboard compressor at the rear of the vehicle, and decided to upgrade the compressor at the same time.
Background
The ARB twin compressor has been around for many years and is a well known, reliable and high performing compressor. I've had one fitted to my current and previous vehicle, and generally it works very well. I've had some sporadic issues with popping fuses, which I think could be a mixture of current in-rush and underspecified wiring. ARB's latest iteration of these compressors replaces the brushed motors with brushless motors - and promises higher compressor performance with like-for-like power consumption. The move to brushless motors also offers other benefits, like the ability for the control circuits inside the compressor to more easily throttle the compressor (to avoid excess heat or voltage drop) and stagger the start-up of the motors to mitigate current in-rush.
Installation
I have the compressor installed in the cargo compartment storage area (under the cargo floor lid). The first step was to replace the wiring from the battery to the rear of the car. I replaced the wiring with 4AWG (6AWG would be sufficient but this gives some room for drawing more power in the future if I want it), and ran it from the battery, down the inside-rear of the wheel arch, along the top of the frame, over the rear suspension, and then through a rubber grommet into the bottom of the cargo tray.
The new unit is a similar form factor to the previous one, but it is not 100% like-for-like swap. There are changes to the mounting solution (it sits on a base plate with a quick release clamp - and the bolt pattern is different), and to the wiring/switch connections (small changes to the setup of the grounds, and the wiring loom simplifies down into two plugs only - one for each compressor pump). The width and height of the unit is I think the same, but it has slightly more depth.
You will note from the wiring diagram that the fuses are now 60A per side. The compressor is specified to run at 45A per motor (90A total) steady-state, but the additional 15A being for current in-rush. I would suggest that if running a long wiring run, as I am, the wiring is sized to the 60A per side requirement.
First Impressions
The installation was easy - the instructions are super clear, the included wiring harness, switch etc makes it all very easy. The hardest part was the cable routing! The unit is designed to use car chassis grounds, so you only need to run positive wires and then pickup on good chassis grounds local to the unit.
It's loud! It's noticeably louder than the unit I replaced. You wouldn't want to sit in the car while it runs continuously.
The clincher - performance! I did a back to back test of the old unit to the new. Taking my 35" KN02's from 7.5 PSI to 35PSI using a four-hose setup - ARB Twin Compressor (old): 609 seconds, ARB Brushless Twin Compressor (new): 407 seconds. This supports ARB's claim of 50% higher throughput (in volume).
Conclusion
Another high quality product from ARB - again a very nice design, good quality of wiring harnesses and physical installation, and top-end performance.
Is it worth the higher price point however...? If you already have the regular ARB twin, then I don't think it's worth a change at the moment. If you are installing onboard air for the first time and you're looking for a premium solution - then I can recommend this.
As always however...none of this is essential if you're just starting out...something cheap and effective from the usual outlets in Dubai will work just fine too!