Should you chip or flash tune your 4×4?

190902 Tuning Guide (1 Of 5)

We decode the current options when it comes to getting the best out of your diesel engine. So, should you chip or flash tune your 4×4?

Words by Wes Whitworth and Martin Donnon: Until very recently the quest for more power and torque from your 4×4 via electronic means was the sole realm of the plug-in or wire-in performance ‘Chip’. Heady advertised gains of 20-percent-plus torque and matching numbers of increased fuel efficiency have seen the concept of the ‘chip’ embraced by the 4×4 market like no other in the automotive sphere.


There is good reason that the process of ‘Chipping’ has become popular too, as in a lot of instances they do in fact deliver the claimed gains and generally increase the fun-factor and towing power of your 4×4. Like most popular automotive trends though the market has been overrun by a plethora of cheap options that have ridden the wave of successful quality chips, and left enthusiasts with a certain murkiness to the process of picking the right tuning solution that will not only deliver the claimed gains, but do so without causing potentially major reliability issues.

Then out of left-field over the last 18 months there has come a new player, the ‘Flash Tune’. While the concept of ‘re-flashing’ the factory software isn’t something new to the performance car market, it is indeed a relatively new concept for the 4×4 arena, as heavy software security which kept Flash Tuners out of the diesel computers innards have been ‘cracked’, allowing relatively free access to the vehicles native operating system and code.

With such a smorgasboard of tuning options available to the market making the right decision to power up your 4×4 has never been more confusing, nor, in-reality more full of potentially risky decisions. It’s time then that we do more than scratch the surface and have a look at both options in more detail.


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Piggyback Tuning: Plug-and-Play Tune Chip

Plug-and-play ‘Chips’ are the easiest and simplest option. They are often the ‘go-to’ of upgrading, as they’re relatively simple, easily accessible online or through performance shops, and in some instances when supplied as a complete kit can be installed by you.

Normally these kits will include a ‘chip/box’ with a wiring harness that you mount in your vehicle, which piggybacks off your current ECU (Engine Control Unit). In some instances, for older vehicles (where warranty isn’t an issue), they will need to be wired into the existing loom, which is normally a job for a trained technician.

How do they work?

The cheaper options on the market that come with a single or maybe a couple of plugs simply plug into the fuel pressure sensor on the rail and report less than target fuel pressure, which makes the factory ecu respond by increasing fuel pressure and delivering more diesel to the engine. This can work in some instances, but our advice is to look for more comprehensive solutions that are more sophisticated in their operation, and in-turn deliver a far better and more reliable result.

One of the best ways to pick a high-quality Chip is to have a look at the number of connections and/or the size of the loom that comes with it. The more connections, the more parameters the chip is able to control, the better the result. Good quality Chips will at least control diesel injector timing, boost pressure, injection quantity, by reporting a ‘false’ or ‘bent’ signal back to the factory computer which in turn overcompensates the real values to deliver increased performance. Sounds tricky, but done right its an approach that can work very well.

Benefits of a Plug-and-Play Chip?

The beauty of a chip is, as the name suggests, they’re plug-and-play. Most of them can be installed by just about anyone (though, some are a much longer and involved process and require quite a bit of work), and should you sell your vehicle, or need to take it back for warranty repair, they can be removed.


While a high quality Chip can be considerably more expensive than a Flash tune there is the option of either having it recalibrated (in some instances) to suit a new vehicle, or being able to sell it on to recoup some of the cost down the track when its time to trade in.

Drawbacks of Plug-and-Play Chips?

As with everything, there are drawbacks. First and foremost, not all chips are created equal. An $150 eBay chip is invariably going to do either harm, or nothing. So make sure you get a quality chip. We have already mentioned this but the old adage of ‘you get what you pay for’ holds very true here.

Since there are additional wiring connections/electrical hardware added to the engine bay there is also a chance (depending on the quality of the kit you select) of reduced reliability via wiring not being as resistant to moisture and dust as the factory wiring. The reality is that it is VERY hard for an aftermarket supplier to reach manufacturer levels of quality in this area. These problems are normally fairly rare, but do your homework and look for high quality connectors that look like they belong in your engine bay.

Last but not least is the diligence of checking what it is you have purchased. With most common modern turbo-diesel engines weighing in at $15,000 plus for a rebuild should something go wrong, we consider it mandatory to have the vehicle checked on a reputable chassis dyno both BEFORE and AFTER fitment of your Chip. Of course there will be an extra cost associated with this. Keep it in mind.

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ECU Remapping: Flashing the Tune

Flash tuning the ECU involves a tuning house armed with a laptop and interface cables rewriting the internal maps and other settings that the ECU holds in the onboard software within the EEPROM (Erasable Programmable Read-Only Memory – memory chip within your ECU that contains the software).

Flash tuning is best described to those new to the game as upgrading the firmware in your phone, or changing the operating system on your PC. There is no addition of hardware, nothing tanglible you can walk away with in your hand (other than the dyno sheet), and as such you need to look at picking the actual tuner carrying out your job as the most crucial part of your investment.

Common-sense decrees that this once more should be carried out on a chassis dyno to deliver the best and safest result, and thankfully this is the way most reputable Flash tunes are carried out.

How does a flash work?

Essentially a Flash tune allows a tuner to look at the host of maps kept within the software of the ECU and tweak a combination of them to get the best power and torque figures out of your specific vehicle. It leaves the sensors and their data alone and has the ECU act differently based on the data received from the engine. It also allows customisation of settings like DPF burn frequency, and EGR efficiency.

Flash tuning is the purest form of tune, in that you’re not messing with sensor data and signals. You are just changing how the ECU responds to those signals. This removes the chance of a signal being missed or modified outside what the ECU sees as normal (think limp mode).

Benefits of a remap?

Since a proper Flash tune allows access to most all of the software that runs your engine, the abilities to perform special tasks are unparalleled. The most important of these tasks (and the least understood) is the ability to change the ‘Torque Management’ of the diesel engine.

Instead of tricking the engine into making more torque like a Chip, a Flash Tune will request more torque (which the engine will then produce), and most importantly signal this via the vehicles internal wiring network to the transmission, which in the case of an automatic will increase shift and operating pressures to prevent slippage and gear-shift issues.

Look at the Flash tune as being a potentially more complicated beast (which is why you pick your tuner carefully), but one that can deliver the most harmonious result with the engine and transmission working in perfect synergy along with all your supporting modifications when carried out correctly

Drawbacks of a flash tune?

There are very few drawbacks to a Flash tune when it it carried out correctly. Just as with cheap Chips there can be some poor results, but these are generally less frequent due to the cost of the equipment required by the tuner to carry out the

Flash tune task. These folks have invested in their business to deliver the result, and as we have said, research your Flash tune operator carefully.

Before handing over your hard-earned dollars also ensure that in the instance of the manufacturer ‘Flashing over the top’ of your new map (as part of a field service recall etc) that your tuner retains your modified map that can be re-installed. This doesn’t happen often but it’s an important box you need to tick when going down this path.

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Warranty Concerns

As with all modifications to your vehicle, be mindful of how it will impact your warranty. Both Chips and Flash tuning are reversible or removable, so if you have a warranty issue, you can return the vehicle to factory specs. There are however several fingerprints that CAN be left behind to inform a manufacturer you have modified the vehicle.

Becoming increasingly more common is the instance of using ‘Tamper Proof’ bolts and clips around the ECU (think all models of Amarok) which will alert a service department to when a plug in wiring loom Chip has been installed. Flash tunes too can leave a digital fingerprint in some instances via tripping a ‘Flash Counter’ hidden deep in the vehicles body electronics which will report a greater number than factory recorded vehicle ‘Flash Requests’.

In short, our best advice here is to be honest with the manufacturer that you have indeed had the vehicle tuned should you go down that path … which is why we keep repeating the necessity to pick quality parts and people when its time to upgrade your rig.




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