ChrisW

Thank you, @JeromeFJ - that was a fun drive with some nicely paced sections allowing both practice of tighter more technical skills along with the longer, faster, more flowing sections. Despite having driven Sweihan many, many times - some of those tracks were new to me and very fun! I was also impressed with your patience breaking into the dunes to the west - it paid off! Team FJ to the rescue!

Thanks for a fun drive today, @Davie Smooth_Operator. Everyone drove really well and kept their cool even as the temperatures came up. Plenty of variety in conditions to practice fundamental techniques…good practice for all experience levels. Also thanks @Benje_Junior, @Mark B and @Luke K P for supporting - with extra thanks to Luke for the coffee!

This is something I ended up messing around with recently. Basically on the Wrangler the auxiliary battery is connected in parallel to the main battery almost all of the time, with the two being separated briefly during the engine start (where the voltages can be checked separately) and during an Engine-Start-Stop event (where the aux battery is used to power the cabin load, eg items like the air blower fan, radio/onboard entertainment etc) such that the main battery is preserved for cranking the engine. If the auxiliary battery or main battery goes bad (happens reasonably often), because they sit in parallel most of the time, they’ll tend to kill the other battery fairly quickly. That’s how you often end up having to change both at the same time. As an FYI, if anyone should wish to change the aux battery themselves, it’s easier to remove the fender (four bolts, one push pin, and replace a few clips on the reinstall) and drop the battery tray…looks extreme but it’s a fairly easy job and can be done in under an hour: The access from below is much easier than pulling out the fusebox. You could also isolate the aux battery and disable it… There’s an argument to be made that the incorporation of a second battery in this way (dissimilar sized batteries running in parallel) is a really bad piece of design that was rushed into place to meet restrictive US automotive emissions regulations. There’s a negative cable that runs from the aux battery to the main. If you disconnect and isolate that, remove fuse F42, and persistently disable ESS (using eg a Tazer JL Mini), then your car will happily run on the main battery only - and probably have much longer battery life in that setup. However there’s also a good argument to be made to just leave it as it is and lean on the warranty!

So I’ll promise to stop spamming the air compressor threads soon! 😬😂 I recently upgraded my onboard air, and as part of that, installed the ARB Pressure Control and an air tank. The air tank does not make anything appreciably faster. But there is a logic which I’ll explain… ARB Brushless Compressor, pressure controller, manifold and valves (going up to a reel air hose mounted on the roll cage). This setup will be made tidier once the line adaptive arrives and I can remove the manifold and connect the line directly to the solenoid valve block. Air tank mounted to the underside of the car, roughly placed under the driver’s side passenger footwell. The ARB pressure control is a nice-to-have in that you can hook up a four-hose line, preset the desired pressure and leave it running automatically while you go and do other stuff (…take down flag, pack gear away, swat flies, send the other half increasingly fictitious reasons as to why you’re running late to the afternoon event that you totally forgot about). However the controlling algorithm is really dumb! Most auto inflation systems would do something like this: 1.) Measure the pressure 2.) Apply pressure for a short period of time (say 10 seconds) 3.) Measure the pressure again and guesstimate the time required to reach the target pressure (based on measured pressure now, target pressure, and pressure gained during the short fill) 4.) Do a long fill for half the time you expect to need 5.) Stop, measure (should be roughly halfway to target pressure), recalculate, go again. 6.) Stop, measure, fine tune to target pressure - done The ARB controller instead stops every 15-20 seconds and measures the pressure. This stop-start is short, but if you have the compressor directly connected to the line, you’re cycling the pump on and off repeatedly (solenoid valve closes, pump runs until it quickly hits the 150 PSI cut-off, turns off until solenoid valve opens again). If however you have an air tank in the mix, when the ARB controller closes the valve to measure the pressure, the pump can keep going and top up the air tank. When the valve opens you get a quick extra burst of pressure, and the pump runs continuously. Testing on a like-for-like basis, the time to inflate my 4 x KN02’s from 7.5 PSI to 35 PSI did not change without (manual method, by hand) and with an air tank (with ARB controller); however with an air tank, the pump ran continuously and did not pressure cycle repeatedly. There are some secondary benefits - using air tools and having a quick burst of pressure for a stubborn pop-out…but this would be a rare use case I expect.

Agreed - when you run the numbers, most pumps can supply volumes well in excess of what one Schrader valve will admit given the surface area of the value and the pressures the pumps works out. The heating effect then comes up in a few ways: as described above the air line chucks will heat up (most pressure at the tightest constrictions), you will also find the pump will work harder against a higher pressure head due to the constriction. This can be measured indirectly by the number of popped fuses people get when turning the pump on against already pressurised lines! All things being equal, for most dedicated air compressors, a multi-hose setup will be a much better match of flow rates (in terms of time, lessening the work done by the pump, and heat). From memory the twin ARB compressor is a total waste of performance for single hose inflation, and mostly only makes sense once you start filling four tyres at once.

Thank you, @nithish468! I really enjoyed the winter fit this year! I think for me some honourable mentions must go to @J-P L (love seeing the Jimny’s and it gave me great faith driving alongside someone else with a manual transmission when I had the old JK), and@Mark B and @Zed for their unstoppable tinkering with their cars! My vote however will be going to @Marek…love seeing that beast out on the sand, and if I wasn’t already setup with the JL I’d definitely have designs on chasing a similar setup!

A wonderful drive last night, thank you @M.Seidam - a great area to drive in the dark, and you hosted a very generous desert suhoor! A couple of videos of our convoy… Qudra Night Drive 1 Qudra Night Drive 2 A nice night with new friends and old: Ramadan Kareem!

Amazing drive today @Looper - thrills and happily no spills on some great lines today in Sweihan. Thank you! A few videos off the 360… Looping off the ridge… Ridge Climbing… High Ridge Cross…

Just had a quick look… The single compressor is rated for 50% duty cycle, 30 minutes on followed by 30 minutes cooling. The cut-off kicks in at 115 degC. If the compressor was left in the direct sunlight today and sat on the floor, there’s a good likelihood it would hit 115 degC after running for a while. There’s a few things you can do: - Sit the compressor in the shade (less heat due to sun) - Make sure the air filter is clear and the air chuck at the end of the hose is also clear (good flow, motor works less hard against any resistance) - Ensure good contacts with battery (running motor at lower voltage can result in higher heat) - Use a two hose or four hose setup to fill multiple tyres simultaneously (more efficient)

Hey Mike - it was buried a bit further down in the write-up but I did a back-to-back comparison between the brushed twin and brushless twin:

People never believe me when I tell them how you pump your tyres up after an offroad session… 😉😂😂

No - I don’t think think it’s been released here yet. This was imported. I did notice some major price reductions from ARB UAE for the existing compressors, which makes me wonder if they’re clearing stock ahead of the new product arriving.

...review added for the ARB Brushless Compressor: https://carnity.com/forums/topic/19672-arb-brushless-compressor-first-impressions/

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!

So green! It’s a good challenge for the optics and sensor…massive extremes of intensity.

I took this in June last year - loved that juxtaposition…a UAE journey from start to today in one frame.

Looper by name, Looper by nature! Really nice drive again, thank you, @Looper - straight into the desert from the start point and some nice climbs along Badayer’s taller dunes. Bit of traffic along the way but nothing too crazy. We had good lines which allowed us to keep the speed up, leading to this fun moment… https://youtube.com/shorts/nfeTSU1aiEU?si=2PbvVqxh3NP8D9KZ The drive delivered exactly on the brief and everyone kept it flowing well. Looking forward to driving with you all again!

Thanks @Looper - good plan and I’ll be there promptly. Fully agreed on skipping the busy areas.

Thanks again, @Looper - that was a challenging drive led with calm focus. Your briefing mentioned a technical drive on high dunes and that’s exactly what this delivered. For me this was a good opportunity to practice technical skills on trickier terrain, recovering myself using my own winch, and a fluke opportunity to use the car-lift airbag! A good morning out. Thank you as well to @Rajiv Sam for being easy to follow, @Emanuel for the recovery support (…I’m also sure I kept mixing your name up…apologies!), and @Anoop Nair for keeping us together.

Thanks @Looper - looking forward to it!

Get well soon @DP1011, looking forward to driving with you soon I hope! Thank you @Looper, see you in the morning.

What a brilliant - and long! - day out. @Asif Hussain you led an excellent drive today, thank you…wonderfully paced, safe at all times and really fun. Quick one from the camera…

I’m rather looking forward to this! I happened to be out in the same area last weekend. We found a really nice bowl/ridge down by Buggies Dune: N22° 50' 46.8" E53° 41' 58.5" Little video clip of it here… https://youtube.com/shorts/JjZ2WbZiDIQ?si=Lcard1cYe5DMAtbL

Congrats @Aser, great news!