How to build a custom 4x4

Imagine being a billionaire for a minute. Not even a go-to-bloody-outer-space kind of billionaire like Elon Musk or the bald fella who looks suspiciously like the bad guy from the Superman movies.

I’m talking your run of the mill billionaire. The hedge fund managers and bitcoin nerds. There’s about 2700 of them at the moment and they’re all capable of spending dumb amounts of money on whatever their hearts’ desire.

What would you park in your garage? I reckon I’d have an F150 Raptor for a daily runabout, parked next to a big Ram 3500 with a canopy for a tourer, and a soft-top FJ40 on coil-overs and 37s as a weekend toy.

Hell, if I was a billionaire I reckon I’d have an aeroplane hanger full of every kind of 4x4 imaginable from wild to mild – rock crawlers, racers, big comfy tourers.

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Sadly, the last time I checked my bank account I had a few less zeros than Jim Walton’s $60,000,000,000. About 10 less now, if I think about it. That means I have just the one 4x4, and it means I have to choose my modifications carefully – I can’t afford to be redoing things, and I sure as hell can’t buy a second 4x4 to suit my whims.

We’re taking a wild stab in the dark here and figuring you’re probably not a billionaire either, so a handy guide on how to build a 4x4 once and build it right should help keep your hard-earned in your pocket.

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The less you need to modify a 4x4 to suit your needs, the easier the job will be

Here, we’re talking everything from the material your roof racks are made from to how many pillows you stuff inside your swag. Thousands of dollars of hard-earned lessons from 4WDing in just about every region of the country. It’s not going to be pretty, and there’s going to be some uncomfortable truths, but you’ll be one step closer to that billionaire list after our advice.

What’s the game plan?

In the age of FOMO (fear of missing out), people are more and more frequently building a 4x4 based on something they’ve seen rather than their own specific needs. It’s not really an issue we saw before everyone was glued to their phones 24/7.

Back in the day you’d go camping with your mates, it’d inevitably rain, and you’d get wet. The next time your mates saw you, you’d either have an awning bolted to the side of your roof rack, or a tarp and a couple of poles shoved in the back. The need would present itself, and you’d modify your 4x4 to suit.

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Danny Reber: “For me, step one to building a heavily customised vehicle is being honest with yourself. Build the rig that suits what you actually do – not what others do or think is cool. Chasing Instagram likes will end up with you spending a bunch of money building someone else’s dream rig and not the one that really suits you. Don’t be afraid to do it differently – to break the mould.”

These days people will see a rig with a big, slinky suspension and decide they need the same. Forgetting they’ve spent the last 12 months decking out a big camping canopy and rooftop tent that all raise their centre of gravity.

By trying to make their tourer a rock crawler, they’ve made it worse at both and spent a fortune in the process. The result is more money wasted. Buying a new suspension again, or selling the canopy at a massive loss second-hand because they’ve decided they want to rock crawl now.

It might sound a little basic, but there’s a reason we’ve put this one front and centre. Before you buy a single accessory for your 4x4, or even the 4x4 itself, decide what your goals are and if the modifications you’re doing will actually help you towards the end goal.

That comp-spec low-profile bar will look a million bucks, but if you’re building a tourer you’ll probably find yourself selling it at a loss to buy another bar at retail with headlight hoops for ’roo country.

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Alloy bar work is a clever way to provide the protection you need without destroying your GVM

Best foot forward

No, the 4x4 you like isn’t the best option for everything. A Prado doesn’t go “everywhere the big boys go”, and a GQ isn’t the most comfortable tourer around just because it’s got coil springs and expensive shocks. Different 4x4s have different pros and cons, and starting with the right platform can save you an absolute fortune in the long run.

Let’s throw out an example here. Dave wants a tourer he can drive from one side of the country to the other in comfort, then punt it up the hard tracks on the weekends. An IFS dual-cab ute ticks both boxes, they’re outstanding for noise, vibration and harshness (NVH). They’ll make a dual-cab Cruiser look like a dinosaur by comparison, and are around $20K cheaper. Throw in a locker and some mud tyres and they’re pretty damn capable too.

Want to go to the extreme and do a solid-axle swap on your dual cab? You’re looking at $30K to do that mod, making you $10,000 more expensive than the Cruiser. And $10K buys a lot of sound deadening and a very fancy stereo to nice up the Cruiser. Our mate Dave would have saved money and had a more reliable rig out of the gates by buying the platform suited to his needs.

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Big offset wheels might look the part but can hurt your wheel-bearing life and require huge modifications to fit

It’s not that one is better or worse than the other; it’s that one is more suited to the job you’re asking of it and will achieve it easier with bolt-on parts. That solid-axle Hilux may get two inches more articulation, but it’s gotta be engineered, will be off the road for months for the work, and is full of custom parts you won’t find at Oodnadatta. It’ll be cool as hell, but is cool worth $30,000 to you when a near stock TJ Wrangler would be just as capable for $15,000?

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Flat rack or basket? Both have their pros and cons, so consider your needs

Ask yourself seriously if the 4x4 you like is the right 4x4 for your needs. The opposite is true as well. As cool as a decked-out Cruiser looks, a mildly modified dual-cab ute will be far nicer to live with every day, especially when your focus is beach runs and weekend camping trips.

Write down the pros and cons of the different options. Factor in parts availability, capability, what future modifications will look like if you get out of hand, and how much you’re financially willing to sink in to the project to achieve your goal. For some, a five-inch lifted GQ on 37s will be the right choice. For others, a Rav4 could be perfect.

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Building on a solid foundation

You've chosen the 4x4 right for your project, begrudgingly accepted that you’ll probably spend more time driving it to work than wheeling double black diamond trails, and now you’re rolling out the spanners ready to start modifying it. Your 4x4’s suspension system isn’t just the part that dictates how high from the ground it’ll be. It affects how it’ll perform on- and off-road, how well it’ll deal with loads and towing, and how fatigued you’ll be after driving corrugations for 10 hours.

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Live-axle conversions on dual-cab utes are hugely popular. While they’re not cheap, they do give huge boosts in capability

The first thing you’ll need to consider is how high your 4x4 needs to be. As a general rule of thumb (yes, there’s always exceptions) the higher your 4x4 the less stable it’ll be and the more you’ll have to spend to make it work right.

In most rigs, around a 50mm lift will let you step up a size or two in tyres, which is where the real capability comes from off-road. Live-axle rigs can typically be lifted to three or even four inches over stock with easy bolt-in kits, while independent rigs will typically require body lifts or goofy bracket lifts to go above two inches without maxxing out the stock suspension design.

A two-inch lifted vehicle on 35s with modifications to the guards will outdrive a comparable four-inch lifted vehicle with 33s, and all with a simpler suspension system and less concerns with legalities.

When it comes to choosing the shock absorbers for your 4x4, it’s typically a case of the more you spend, the better the result. A spring’s job is to keep your 4x4 in the air and handle the weight, the shock absorber’s job is to smooth out the bumps. The better the shock is at smoothing out the bumps, the better the ride quality and the less you’ll have to fight the steering wheel to keep you pointing down the track.

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Popular models are more likely to have off-the-shelf solutions like coil conversions and camping set-ups

Typically, shock absorbers can be looked at in three tiers. The entry-level set-ups will cost around the $1000 to $1500 mark for shocks alone and can offer a slight improvement in ride quality and a boost in reliability.

From here, the $1500 to $3000 range starts introducing rebuildable shocks and increased oil capacity through external or piggyback reservoirs. The additional oil capacity helps stave off shock fade in corrugations and undulating terrain, and the higher quality valving will give a smoother ride.

From here you’re in to the high-end shocks where the sky is the limit. They’ll offer similar features on paper as the second-tier offerings, but will typically be fully rebuildable and tunable by a quality shop to get them dialled in exactly to your needs – more oil capacity, better valving, huge increases in strength. Big, fancy shocks predominantly benefit tourers rather than hard-core weekend wheeling, but both benefit from as low a ride height as you can get away with.

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Don’t need to use the back of your 4x4 for large items? Storage drawers are a great way to organise camping gear

The final piece to the puzzle is your load-carrying ability. You can imagine how bad your 4x4 would ride if you put springs from a Mack truck in it; getting the spring rate wrong is no different. If your 4x4 is always loaded up the same, then constant-rate springs will be the simplest option. If you’re constantly changing what’s in there, or occasionally towing, an adjustable air-bag helper set-up can dial in your spring rates to suit the day.

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Dilhan Otay: “The ideology of building a 4x4 suited to you once is a dream concept! Don’t be afraid to ask and bugger up a few things along the way! Your needs as you grow with your 4x4 will constantly change. Key advice will be to use quality products and really think about how often it will be used. Do it once, do it right is the best concept to mould your dream 4x4, whether it be your weekend track tackler or your family tourer.”

All barred up

Short of the wheels and tyres, your 4x4’s bar work is one of the biggest deciding components for what your 4x4 excels at. You could have two identical GQ Patrols. Both three-inch lifted on 35s. Both with big angry turbos hanging off the side of a TD42.

One is sporting an ARB plate and post front bar, matching scrub bars and a Kaymar rear bar. The other has a custom tube bar tucked high and tight going in to custom rails and sliders from front to back with a one-off rear bar. It’s immediately obvious just from looking at the two side by side which spends its weekends wheels up and winching, and which one has seen more of Australia than the kangaroos.

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If you’re not punting into rocks daily, alloy bash plates can provide ample protection for a fraction of the weight

The two biggest choices you’ll have with your bar work is steel versus alloy, and low profile versus full hoops. Steel versus alloy is a question you’ll need to seriously ask yourself between your uses and desires.

Steel is a must if you’re doing remote touring and animal strikes are a real concern, but it will eat into your GVM, potentially tipping you over the scales into illegal territory. It’s also preferable if you’re punting your rig into rocks 300 times a weekend.

On the opposite end of the spectrum, alloy bar work can still give much needed protection to the radiator but won’t hold up to sustained strikes. Alloy bars can still mount driving lights, recovery points and winches with a fraction of the weight, so still have their place.

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Factory side-steps are easy to use and lightweight, but you’ll need steel rock sliders to give serious protection to your sills

Ditching the factory side-steps is another common upgrade people tick the box for without considering their options. Heavy-duty rock sliders will give you the peace of mind you can tip your sill panels in to a rock or tree without serious damage, but there are not too many rock ledges in the Simpson Desert to give you grief, and you’d save yourself $1000-plus and 50kg out of your GVM running factory side-steps.

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Just because something doesn’t exist, doesn’t mean you can’t have it. Custom solutions exist for anything your heart can desire

Likewise, the need-vs-want ratio needs to be considered when eyeing off a rear bar. They’re fantastic bits of kit if you need them, giving you a sturdier mounting point for your heavier spare tyre, mounting points for jerry cans and much needed rear-quarter protection. But if you don’t need those features, you’re spending thousands and eating considerably into your GVM purely for aesthetics. What you need is more important than what you want.

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Custom work is only as good as the person doing it. Before putting your pride and joy under the knife, make sure you know what the end result will actually be, not just what you hope it’ll be

The final piece to the puzzle with bar work considerations is your roof rack. In years gone by they were all steel, all huge and all heavy. These days the prices have risen, but so have your options. Alloy flat racks promise huge versatility for bulky items without adding too much weight to the roof, while baskets provide a handy place to stash small items like camp chairs and firewood. There are few downsides to either option, so personal taste holds as much weight as practicality.

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Lal Morris: “DON’T be afraid to ask people for help. You can build your 4x4 while you build your knowledge on it. And don’t rush, do it once, do it right. It will save you money in the long run.”

Pitching tents

When it comes to camping, more gear normally makes for an easier camp. Expensive lithium battery set-ups, 12V coffee machines, electric-opening tents and even inflatable swags are all the hottest trends of the day. But it all costs money and adds weight.

Take for example the latest trend of hard-shell rooftop tents. They’re one of the easiest camping systems on the market, being able to stash your bedding and full sleeping set-up in one box that takes 30 seconds to erect. The downside, and there’s always downsides, is that convenience will take up your entire roof rack, massively eating in to your storage space and practicality.

And with many of the hard-shell rooftop tents tipping the scales at 60kg, even if you’ve got a garage you can fit in and a winch to lift it on and off, odds are it’ll live on your roof until the day you sell it.

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If you don’t need roof storage, hard-shell rooftop tents provide the ultimate in comfort and quick set-up

Once it’s up there, your roof is dedicated to sleeping. If you’re camping every second weekend the comfort and convenience can’t be rivalled; but if it’s your only vehicle, a single swag with a thin sleeping bag and inflatable pillow will cost roughly 1/8th of the price and can be thrown in the back seat.

It’s just one analogy, but it rings true for every component you can think of when it comes to camping comfort. Convenience adds complexity, cost, weight, and limits how practical your 4x4 is when you’re not camping. From drawers to ute canopies, to fancy electrical systems. Decide where the balance point for you lies and don’t let yourself get carried away. It’s an expensive lesson to learn you’ve tilted your 4x4 too far in one direction.

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Custom storage solutions can be tailored to suit your exact requirements and not just what sells best

The other factor to consider is that an extensive camping set-up won’t just affect your GVM and storage space, but it’ll directly affect how capable your 4x4 is in every situation on and off the road. Heavier 4x4s are more likely to get bogged, work harder to drive through sand, and are more tippy when doing technical wheels-up 4x4ing.

You might be happy to spend the $4000 on that fancy rooftop tent, but are you happy with the instability it’ll introduce to your weekend wheeling set-up?

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Under the bonnet

If ever there was one invention responsible for the ongoing keeping up with the Joneses’ syndrome it’d have to be the dyno. While numbers on a sheet of paper are always fun to look at, it’s transformed the goal of engine modifications away from how capable your rig is, to how impressed everyone will be by it.

Let’s get one thing straight, with very few exceptions reliability and engine modifications are at opposite ends of a straight line. The closer you get to one, the further you get from the other.

Of course, there are exceptions with upgrades like intercoolers, hard pipe kits, and transmission coolers that, while adding some level of complexity, far outweigh it with their benefits. But if you’ve got dreams of having a 4x4 that’s an absolute animal with the loud pedal, you’ll give up a little peace of mind in touring conditions.

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Engine conversions are a great way to get more grunt from your 4x4. Where possible, factory options help simplify the process

As a result, mild performance upgrades are the most common seen as they can have reasonable boosts in performance and driveability without drastically affecting reliability, as long as the work is done to a high standard. ECU re-mapping and turbo-back exhausts can be had for a few thousand dollars with 20 per cent increases in power and torque.

From here you’re looking at bigger injectors, bigger pumps and bigger turbos. Reputable shops can guide you towards reliable set-ups and advise on how far you can push your engine before you start running in to reliability issues. The budget you allocate won’t just dictate how much power you can expect to find under your right foot, but how reliable it’ll be.

Off-brand turbos, second-hand intercoolers, and suspect heavy-duty transmission valve bodies from AliExpress can all push out big numbers on the day of installation but aren’t something most people would feel comfortable crossing deserts with.

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Popular models will have common reliability upgrades that should always be looked at before chasing more power