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Flash tuning 101: ECU Re-mapping

By Dan Everett, 15 Apr 2017 Electronics & Gadgets

Flash tuning 101 ECU Re mapping cover

The ins and outs of the black art of ECU re-mapping.

LURKING inside the kick panel of your 4x4 is a computer so powerful NASA would have paid millions for it to help put man on the moon.

It controls every single aspect of your 4x4, from the rate the indicators flash right through to how long each injector pulses open, as well as the angle of the blades inside your turbocharger at a given RPM. They’re an incredibly complex bit of kit, so it’s no surprise that when people started pulling them open and rewriting their code it made more than a few people a little nervous. After all, manufacturers have things absolutely perfected, so any modification is a recipe for disaster, right? Not exactly.

To help cut through some of the fog surrounding re-mapping, or flash tuning as it’s sometimes known, we’ve enlisted the help of four of the top diesel-tuning experts currently spinning err… keyboards on late-model diesel engines in Australia: Brendan Cook from Diesel Power Unlimited, Paul Farrell from Geelong Performance Centre, Matt Smith from Just Autos, and Stephen Booth from Power Torque Victoria.

re-mapping a RangerTo understand the pros and cons of re-mapping, as opposed to a simple performance chip, it’s important to have a solid understanding of the major differences. Electronic diesel tuning has been around for almost as long as electronic-controlled diesels, and early models were incredibly rudimentary with very little that could actually be changed.

Performance chips were perfect for this, as all they had to do was alter some of the half dozen signals the ECU was getting and the ECU would compensate for it. If the tuner wanted more fuel pressure at the injectors, the chip would tell the ECU there’s less pressure than what is actually there, forcing the ECU to ramp up pressures to compensate.

Scan tools for your 4WD

Rather than improving on the chip-style of tuning previously used, re-mapping is an entirely new way of looking at things with a whole host of benefits. Instead of tricking the computer into behaving how you want it to with a few minor inputs, re-mapping is able to change how the computer itself behaves.

This opens an enormous amount of control for the tuner, allowing them to make the engine perform exactly how they want; not only giving higher power figures on a dyno sheet, but real world driveability too.“Essentially, in a small amount of way, you can change anything your mind can think of,” Matt Smith said. “Anything from EGRs, boost control, boost limiters, variable vane control on the turbo, engine timing, rail-line pressure, torque limiters – there are thousands of individual maps.”

power graphNot unlike an update for your phone that adds new features, the process involves overwriting the information on the existing ECU. “This is achieved by first reading the stock file from the ECU, modifying certain maps and then writing the modified file back into the ECU,” Paul Farrell added.

WITH hundreds of maps available and endless ways the tuner can customise them, there’s more to the results than a simple percentage increase in power. There are a few factors you’ll need to take into consideration before trusting your 4x4’s brain to a man with a laptop, namely how much power you’re chasing and how talented your tuner is.

With most modern common-rail turbo-diesel engines you can expect a 20-30 per cent increase in power and torque with just a tune; although many stock components will be the limiting factor.

In the case of 70 Series Cruisers, where owners are routinely chasing upwards of 50-100 per cent more power, turbocharger upgrades, larger injectors, free-flowing exhausts and intakes are all mandatory. With some models requiring significant upgrades, like heavy duty clutches and free-flowing intercoolers with even mild power upgrades, it’s important to speak to your tuner about exactly what you’re chasing and what you hope to achieve while you’re still in the planning stages.

“The modifications all depend on the desired outcome and the engine,” Brendan Cook said. “Some four-cylinder engines really benefit from an exhaust, where some actually lose low-down torque and richen the mixture up.”

remappingJust as important as the tune is who is writing it. “There are a lot of tuners in Australia locked to European tunes (slaves),” Matt Smith told us. “There’s only around half a dozen masters in Australia because the software is so expensive; we’ve got $100,000 worth of software so you need to be an IT guy as well as have a solid understanding of performance. If the shop you’re going to isn’t creating the tunes themselves, who is?”

While the figures in some cases may seem similar to those available with a simple chip, the big difference is in the driveability. “Because we’re working directly with the ECU the response time is cut down,” Brendan said. “The big thing people notice is the throttle response and the low- to mid-range torque. When all the maps are managed correctly you can make the engine really sing when it’s down low, full boost is achievable earlier than with most chips, and a clean-air fuel ratio can be achieved which makes for a steep torque rise.”

The power levels ultimately come down to what the owner wants and how far they’re willing to push their engine. Some tuners claim a fuel consumption decrease of around 10 per cent due to the engine not needing to be pushed as hard, but with so much variance and many owners making use of the additional power it’s really a moot point.

WHEN it comes to ensuring the tune controlling your engine is not only powerful but safe, there are a few different schools of thought. On the budget end of the market there’s the set-and-forget crowd who will upload a stock tune and send you on your way. On the custom tune side of things there are a few different ways the tuner will make sure it’s done right.

A dyno, or rolling road that allows the tuner to load the 4x4’s driveline up and simulate driving conditions, is a common sight. One of the big reasons many tuners will use a dyno is the sheer amount of firmware versions available across individual models. “In the PXII Ranger there are five to six different versions,” Matt Smith said. “70 Series Cruisers have 12, so do the 200s, and the Hiluxes have 14 from memory.

solderingThey all look the same but they’re slightly different. Sometimes the tunes are easy and go together quickly, other times they’ll have tiny issues that you need to chase and do the tune specifically for the car. I’ve been working on a Hilux at the moment for four hours to get it right, that’s what you pay for.” It’s this back and forth on the dyno that allows the tuner to identify issues like boost spikes, low air-fuel ratios or excessive exhaust gas temperatures that could lead to engine failure.

On the other end of the spectrum Stephen Booth prefers to rig his vehicles with probes and do his testing on the road. “Although a dyno tune is a useful tool they can only simulate full throttle,” he said. “They are great for setting your limits in boost and AFR but they won’t simulate everyday driving. The best dyno is the road. It’s real-world, and a good boost gauge, AFR probe, pyro and OBD logging are the best tools for tuning. And if you’re going to tow a van we’ll whack it on and go tuning so there are no surprises.”

While the high-end shops are split down the middle on the exact type of test and tune methods they’ll use, all are in agreeance it’s an absolutely vital step to ensure the maximum driveability and reliability from your engine. There’s more to a good 4x4 tune than headline figures on a print-out.

WITH how easily modern engines can damage, and how expensive they are to replace, it’s not surprising that warranties are the first question most people will ask about. While some tuners claim their tunes won’t void the factory warranty, things are a little more involved than that. If a modification directly leads to a failure the manufacturer is under no obligation to cover any of the costs associated with the failure. If you have your engine re-mapped they can’t knock you back on a leaky radiator, but injector failure will be an uphill battle. In theory it’s simple enough, but it gets complicated when you try and put a limit on how much the modification can affect things further down the line.

remapped ECUWill a tune void warranty on your injection system, turbocharger, gearbox, driveshafts or diffs? Both OME manufacturers and the Department of Fair Trading were both hesitant to put an exact figure on where the line gets drawn, making the whole thing a minefield to negotiate. That’s the bad news. The good news is most quality tuners will warranty their own work. If they’ve tuned your engine and it goes bang, they’ll identify the issue and if it was their tune the repairs are on them. Stephen offered a pretty simple bit of advice: “Just get it done right the first time and you shouldn’t have to worry about that argument… ever.”

IT depends on who does it. The same tools that allow a skilled tuner to make a more efficient engine are the same tools that allow a poor tuner to make a catastrophic mess of it all. “As there was with chips, there is with tuning: rogues,” Stephen said. “If your tune was done by a plumber who used to play around with his ski-boat engine and believes the richer the mixture the safer, I would say, yeah, your engine’s done. But if he’s a trade-qualified mechanic and diesel fitter with an in-depth knowledge and can actually explain what boost and torque you should be expecting, I would suggest it won’t damage your engine at all.”

isuzuThe important factor to consider is that lugging around a dual-cab ute and camping gear isn’t necessarily the most strenuous work these engines have been commissioned to do, so they’re often designed for much tougher jobs and can be pushed harder. “A lot of the engines in other applications, like marine, are actually pushed a lot harder,” Matt
added. “The engines are designed to withstand more than what we put them through.

When these engines come from the factory they’re not 100 per cent efficient; if they were we wouldn’t be able to get power out of them. It’s already there. It’s already in the car. The engine is capable of making more power.” In fact, it’s not just marine applications that these engines are often used for. You’ll find various 4x4 powerplants running diesel generators, tug boats and hydraulic equipment all over the world – the 3.2-litre Duratorq engine found in the Ford Ranger is currently in testing for a new fleet of British diesel-electric hybrid trains.

WHILE the thought of putting $1500 cash and your engine’s health on the line may seem daunting, ECU re-mapping is becoming an incredibly common modification and, to be honest, you really do get what you pay for.

engine baySo how do you identify someone who is fair dinkum among a crowd of backyard tuners? Unfortunately there’s no tick of approval out the front of any workshop, so it really comes down to using your noggin. Ask the tuner how experienced they are, not only with re-mapping but with your model specifically. You don’t want to be the guinea pig – if they’re not the person writing the tune, ask who is.

A quality slave tune will be leaps and bounds in front of a poorly written custom tune. Most importantly, look at their reputation and how they present themselves. If they’re doing good work you shouldn’t struggle to find people who will sing their praises. After all, re-mapping is about making your 4x4 perform better on- and off-road, and the last thing you need is the drama of going to the wrong place.


Ph: (07) 4959 3350
W: www.dieselpowerunlimited.com.au

Ph: (03) 5277 2503
W: www.geelongperformance.com.au

Ph: (07) 5476 0066
W: www.justautos.net.au

Ph: 0417 558 799
W: facebook.com/powertorquevic