Additional digital power for a song

No, you really no longer need to be a professional participant in tractor pulling competitions to be able to increase the engine power of your tractor or combine harvester. Moreover, on modern engines, this can be done in various very simple ways thanks to electronics. This technique is called tuning. For cars and trucks, tuning is already very widespread. It's now clearly gaining popularity for agricultural machinery.

English translation - original article published in Dutch by De Loonwerker

Tuners promise to increase engine performance by 20 to 30% on agricultural machinery and reduce fuel consumption by 10 to 15%. More power and more economy, all for a proverbial "song." Who wouldn't take that? Tractor and machine manufacturers, however, have a totally different opinion on this. Tuning is dangerous and moreover unsafe, they say. De Loonwerker has put all facets into perspective from an independent point of view.

Engine technology

Modern engines are controlled by a computer, better known as the ECU (Engine Control Unit). This electronic control unit determines, based on a number of continuous measurements such as injection pressure, turbo pressure, engine speed, engine temperature, accelerator pedal position, etc., the timing and quantity of fuel to inject. All this while of course taking into account the emission standards in force.
Here are some findings. On one hand, engine manufacturers sometimes use digital control technology to create different power for the same engine. This way, the same engine can be used for different power versions. This "factory tuning" is convenient for the manufacturer, as they can thus produce larger quantities of a single engine type. Once adjusted, the engines are certified at the engine manufacturer, after which they are mounted by the tractor or machine manufacturer without further modifications. The engine manufacturer's warranty is thus preserved.
On the other hand, manufacturers provide wide margins in product construction. Both tractors, machines and installed engines are developed by the manufacturer to be used worldwide. They must therefore be able to satisfy extreme conditions. For our temperate Western European conditions, a wide tolerance is integrated as standard. According to tuning companies, this represents about 40% for most engines.
Making an engine work better means introducing more fuel or burning fuel better. The techniques to achieve this are: either increase rail pressure, or increase and/or modify injection times, or combine both. When tuning an engine, these are manipulated and one or more of the manufacturer's set parameters are modified. This can be done by software, hardware, or by a system that intervenes in the ECU's normal operation. All with the goal of achieving more optimized engine management. In practice, this means creating more power and torque with as low consumption as possible. To do this, we obviously nibble at the integrated reserve the engine has.

Many tuning possibilities

Tuning on an electronic injection engine can be done on the fuel pump or on the common rail. Since common rail engines are gaining popularity, tuning is mostly done on common rail engines. The different techniques that have been developed for this purpose all have their own advantages and disadvantages.

A first possibility is remapping. This tuning must always be performed by a specialized tuner. Their working tool is the ECU software. Depending on how modifications are made, there are a number of variants. The oldest method consists of modifying the software directly on a chip in the ECU. The big disadvantage here is that there's a lot of disassembly work. In the end, everything must be perfectly replaced. Not only must the ECU be opened and closed, but the most delicate work is removing the EPROM chip from the circuit board and then replacing it without damaging anything.

A more accessible and more widely used variant is on-board diagnostic tuning (OBD tuning). Here, you just need to plug in cables to have a connection with the ECU. This can be done directly by disconnecting the ECU or by plugging the computer into the vehicle's diagnostic port so that all exchange happens via the CanBus.
During tuning, all software is first read. Then, improvements are made to finally reload the software. Modifications generally concern injection duration and common rail pressure. The value of a number of limiters is also changed. Ziptuning is a company that performs tuning this way. According to Pascal de Graaf, manager for Belgium, they consciously choose to keep the number of modified parameters wide. The art consists of making an ideal mixture and working over the entire RPM range. This broad work has the advantage that existing reserves are reduced only minimally. A sensitive point in remapping is the correct adjustment of parameters. Besides a more efficient setting, great reliability is also desired. This requires a lot of knowledge and experience.
An additional difficulty with this type of tuning is finding the protocols of the engine software. They must be found for each newly developed engine. And as long as the engine manufacturer uses non-standardized protocols, this requires additional research for each newly developed engine before adapted software can be written. Companies like Ziptuning, which have establishments in different countries, therefore have a whole list of engines they can tune. However, a number of very recently developed engines are still missing. Once the engine is known to them, tuning for the customer is performed in an hour and a half. Prices vary considerably and are not always comparable. They oscillate in a magnitude of 1,000 to 2,000 euros.
Tuning directly on the ECU means there's nothing to plug in externally. No external boxes or cables with which something could go wrong. But this also means that in case of engine update, the performed tuning disappears again. Of course, you then have the latest original software again and, according to them, tuners gladly provide new tuning in these cases for a sweet price.

Another possibility is to work with an external box-unit, which is placed between the ECU and the engine. The tuning box will influence certain data from or to the ECU. In recent years, many types of chips have been developed. Each system has its specific advantages and disadvantages. Qualitatively, there are also distinctions between different types with a variation from very rudimentary tuning to more refined tuning. What they all have in common is that they're easy to install. Most are plug and play type and are therefore offered as a self-install kit with provided manual. The oldest principle used in performance chips is rail pressure tuning. It's also the simplest way to get more fuel into the engine cylinders. The simplest in this area are so-called powerbox tuning boxes. This add-on box, which has been on the market for a long time, consists only of hardware, namely resistors and potentiometers. The data flow from the rail pressure sensor to the ECU passes through this box, which systematically lowers the values. The ECU constantly receives false data here. The control reacts to this and strongly increases rail pressure resulting in increased fuel injection. The result is development of more power, but the engine is also subjected to additional load. The most recent engines are protected against this and don't let themselves be adjusted so easily from outside. Internally, the modern engine indeed continuously performs self-monitoring and data is checked against defined values. The consequence is that the engine reduces the sometimes strong increase in rail pressure again by auto-correction, which strongly reduces the effect of this powerbox.

Advanced tuning boxes are full-fledged small computers. For boxes that act on rail pressure, the technique is refined by software. In addition to measuring rail pressure, the box continuously calculates in real time the amount of fuel injected. Some boxes go even further in regulation and don't work continuously but dynamically. Thus, according to engine requirements, engine performance is increased by software. An example of such a box is Speedhawk's XXL Box. The box also has a transmitter-receiver system with which the driver can activate or deactivate the chip. Speedhawk advances as an advantage that with rail pressure tuning, injection timing points are not modified nor are defined limit values.
But only working on rail pressure results in quite a strong pressure increase - about 10 to 12%. The normally integrated reserve of a minimum of about 400 bar can be reduced by half by tuning. An XXL box costs about 500 euros.
In addition to boxes that only play on rail pressure, there are also boxes that only play on injection times to achieve better performance. The P-Tronic Agri tuning box works this way. According to Philippe Heeren of the Walloon company P-Tronic, this is the most efficient and safest method. This involves not increasing turbo and/or rail pressure, keeping all original safety parameters on the ECU active as well as manufacturer tolerances that remain respected. The P-Tronic Agri performance chip works over a wide RPM range with automatic activation as soon as additional power is needed. An integrated safety ensures that the engine returns to its original speed if something is wrong with the box.
P-Tronic also offers remapping but clearly prefers using their tuning box. "That's where the future lies," thinks Philippe Heeren. "A box-unit is user-friendly: easy to mount and dismount, activate and deactivate and it retains certain value because it can be placed on another vehicle after reprogramming." The price of a P-Tronic Agri chip varies from 950 to 1,300 euros.

Finally, there are boxes that combine the two previous systems, so optimization by modifying injection times and rail pressure. In the trade, this is called electronic module tuning. This box therefore has a connection with both the rail pressure sensor and the injectors. Because we work on several parameters, modifications to them should be limited. The DTE-Systems module applies this principle. Distributor of DTE-Systems for Belgium and the Netherlands, Bart van Harselaar has already performed many installations of this type. Not just on tractors by the way, but also on combine harvesters, where apparently tuning is custom work for him. When developing a correct electronic module, a data recorder is first installed that collects engine performance data during work. This data constitutes the basis for further refining the standard module software throughout the engine's RPM range. The box-unit is set so that tuning only becomes active when 80% of available power at a certain RPM is requested. The module also has integrated safety that automatically deactivates tuning in case of too high engine temperature.
Once the software is installed, installation is simple and can possibly be done by the customer themselves. Their advice is to place the machine on the dyno before and after mounting. The price of a DTE-Systems module varies from 800 to 1,500 euros.

What about warranty?

Tuning an engine while the vehicle is still under warranty involves loss of factory warranty. For cars, warranty is quite often taken over by the tuner. For tractors, it's different. On a tractor, you can mount or attach infinitely many things and work with it in very diverse conditions. Most tuners therefore limit warranty to tuning itself, but not all.
For engine tuning, in any way, there is still no official recognition. When tuning, you are therefore responsible for all consequences. So neither the manufacturer, nor the importer, nor the dealer and not even the tuning kit supplier. All factory warranty and certification disappears.
The absence of recognition brings us to the question of how easy it is to detect tuning. Remapping seems to be the easiest form for the manufacturer since modifications have been made to the ECU software. Yet, according to De Graaf, it's not so simple to detect. With good tuning, the manufacturer also has difficulty discovering it. With add-on boxes, which are easy to remove discreetly, it obviously seems even much harder to detect.

But here too, some caution is warranted, because according to tractor manufacturers, internal recording systems are now integrated. They permanently immortalize power, torque and other parameter values. In case of warranty, the manufacturer can request data from it and in case of tuned engine, refuse warranty. Tuners notice that it's not always the machine user who knocks on their door. In this regard, Van Harselaar works a lot at dealer request. "Normal," he says, "because it's the dealer who is confronted with the customer's specific problems and must seek a user-friendly solution." And this can be extended further according to De Graaf because they have also already tuned engines at the machine manufacturer's request. During such an initiative, the customer has every interest in ensuring they receive the necessary documents that place responsibility and consequences with the initiator.

And then, in case of damage, insurance can also pose problems. Playing it safe means contacting your insurance company in advance.

And have you already thought about this

Sustainability makes us all a bit more environmentally conscious again. This is also the case for machine manufacturers who, with increasingly strict emission standards, strive to make agricultural machinery as powerful and economical as possible. These imposed emission standards obviously play tricks on manufacturers when adjusting their engines. Think of the transition from Tier II to Tier III, which meant engines could no longer be optimally adjusted to meet the new standard.
Of course, emissions are never measured directly before and after tuning. Curious how green the aspect remains? Apparently, all tunings shouldn't be put in the same basket, because some boxes even carry the German TÜV quality certificate, mentioning that emission limit values are not exceeded.

The engine only serves propulsion and assuming tuning poses no problem for the engine itself, all other components must still be able to follow during the increase. And that's not obvious. Not even for tractors of the same series. Because even if technical data are identical apart from the engine, a number of components often differ. Take as an example a Fendt 922 Vario (220 hp) and a Fendt 936 Vario (360 hp). Apart from the engine, they seem identical, but internally, they're not equal in terms of construction and components!

To conclude

Tuning or digital engine improvement has become commonplace, certainly for cars. Agricultural machinery differs totally from cars by the other and highly variable conditions in which they work. The problem doesn't only revolve around the engine but around all other parts of the machine that must follow. Caution is therefore warranted. It's a matter of using electronics and not abusing it. Agricultural machinery manufacturers and importers prefer to talk as little as possible about tuning. Yet, one cannot be blind to this technology. Even at international agricultural shows like Agritechnica, different highly reputed electronics companies offer these tuning kits. A development that is still difficult to stop.
De Loonwerker was therefore of the opinion that it's better to inform the user about its possibilities and dangers.

P-Tronic

The P-Tronic Agri performance chip is connected to both the injectors and the common rail. For 4-cylinder engines, connection is made by means of two plugs per cylinder, for 6-cylinder engines, there are three plugs per cylinder. For power supply, a connection is established with the battery.

Power curve

Engine characteristics measured by P-Tronic compare performance without and with tuning box. The thin light blue line represents power, the light green line torque. With the P-Tronic Agri chip connected, the thick blue line represents power and the thick green line torque.