The days of turning the screw in the diesel pump using a vice grip or a 10mm spanner at the side of the engine are a distant memory with farm machinery.

When the Engine Control Unit (ECU) or engine’s computer was assigned the task of governing modern engines’ fuel and air induction systems to comply with more stringent exhaust emissions set by the EU, different tools and a new approach to adding power was required.

A laptop is today’s vice grip and special software known as a ‘map’ is the key to unlocking a machine’s potential. Modern machinery is getting very expensive, and farmers and contractors sometimes want to increase productivity in the field by powering bigger and wider implements at greater speed, so tuning what’s already in the shed may be an option.

Optimum fuel efficiency is another reason to look at altering a machine’s original factory setting stored inside the ECU to match certain farming tasks. The cost of a remap is approximately between €600 to €1000, but owners may be able to squeeze more from their own tractor without adding greater financial burden of newer kit if the right approach is taken.

The terminology

ECU remapping, flashing, chip-tuning, or reprogramming are common terms, but in truth they all mean the same thing. In simple terms the EPROM (erasable programmable read only memory) is a tiny computer chip or microprocessor consisting of millions of layered transistors (microscopic digital switches) housed within the ECU’s printed circuit board, which stores factory-set engine constraints.

This processor is receiving and analysing all the incoming data such as engine speed, piston position, air quantity, and boost pressure, and also governs actuators like the opening of electronic fuel injectors, as well as the duration and boost pressure.

The map is the amalgamation of everything an ECU knows about the engine settings on a digital file. The aim of re-mapping is to connect to the machine and download this original data, tweak it and upload it back into the ECU to provide improved power, performance and/or fuel efficiency.

It does this by altering the fuel injectors’ pulse width or on/off time which is the quantity of diesel that is injected into each cylinder in milliseconds.

While this is all done in the blink of an eye, balancing the volume of air to fuel quantity ratio is the key to power and optimisation of performance. The art of remapping is a practice where these pre-defined parameters are read from the ECU using specialised tools and equipment.

This data is then usually sent to a trained software engineer for modification where desired engine characteristics are targeted to suit the owner’s request. This can often be worded for example as an ‘ECO map’ or ‘Power map’ for various makes and models. As the name suggests, ECO mapping is orientated around better fuel consumption where a Power map is more focused on increasing power requirements, or greater low-end torque.

More power – what to consider

Know your tuner and ensure they are a member of a respectable tuning company that use genuine branded read/write tools and not cheap cloned equipment or inferior map files. Do some research before you offer the job to a tuner and ask where they source their maps from. Remember that remapping high hour tractors or any machine in poor condition is not advised.

Avon Tuning

I recently spoke to Gareth Jones who is the owner/technical director of Avon Tuning. Avon has built a very good reputation in the agri and construction sectors in Ireland over the last number of years for both the service and quality of map it provides.

Avon Tuning was set up in 2010 and its headquarters are in Tockington outside of Bristol, England. It first entered the market with automotive mapping and then expanded to other mobile equipment.

Gareth Jones noticed that the off-road machinery market was lagging behind the auto world, as it was mainly using tuning boxes rather than software rewrites.

“Remapping is very different to a tuning box which would have accounted for a large proportion of the engine tuning market around seven to 10 years ago,” he says.

Gareth points out “an ecu remap and tuning box differ in how they alter engine parameters. An ecu remap involves editing the ECU software and reloading it back into the ECU.

“A tuning box is a piece of physical hardware that plugs into the engine fuel system and tricks the ECU by adjusting input values that the ECU receives.”

With remapping, the original ECU file is downloaded from the machine and it is saved and stored in a secure server if the tractor needs to be restored to its original factory settings.

“Tuning boxes or chips gave the industry a bad name, but professional remapping is improving the image and is much safer, as the installation and map editing is carried out by an experienced engineer.”

Getting good power in the correct way is hard and requires dedication and research.

However, “there are shortcuts used to achieve similar results, but the long-term damage it does to the engine and running gear are costly,” says Gareth.

He adds that Avon has an experienced and knowledgeable team of qualified agents throughout Ireland covering all corners of the country for remaps.

Pre-tuning checks

First the machine being tweaked needs a competent examination. Health checks are carried out and if the machine has previous modifications, high hours or running poorly then any alteration to increasing power is ill advised.

Before applying any remap, the tractor’s characteristics are cross-referenced to make sure any increase in power can be handled by all the driveline components such as engine, PTO pack and transmission etc.

If the tuning technician notices anything that could prematurely fail due to a remap such as a power increase, they will advise the client against it.

According to Gareth, “straining an engine by over-torquing is more critical than over-revving, with the potential to damage critical transmissions components”.

This means that understanding the whole running gear set-up is critical and why trained agents are essential for the task.

Most remapping is done through the diagnostic plug on the machine itself. In some instances, the ECU may need to be physically removed, opened, and using a special BDM frame make a physical connection via pins connect directly onto the microprocessor to read/rewrite new maps. Done professionally, this is not an issue.

Consider the limits

Anyone looking to add performance to a machine needs to do some thorough investigation work and determine if important engine components can take the extra power.

The models at the top of a tractor range may be similar in lots of ways to the next model or two below it.

Take any of the top tractor brands as an example and they may have a range with 180hp, 200hp and 220hp models. The next highest horsepower model of say 250hp will be bottom of a bigger range, but will be mechanically totally different with possibly heavier axles, bigger tyres, larger PTO pack, bigger cooling package and heavier transmission parts etc.

The 180hp model or 200hp model may have plenty of capacity and capability to be remapped to match the top model of the range, so in this instance, max 220hp.

However, changing the top model of 220hp to match the next size up against a different range to 250 hp would not be smart! It is vital to safely increase power and torque within the limits of each machine’s capabilities.

Fergal O’Sullivan is a lecturer in the agricultural engineering department at Munster Technological University (MTU) Kerry.