Tractor tuning for more power

Over the last few years increasing numbers of farmers and contractors have been tempted into fitting aftermarket tuning devices to their tractors and harvesters. This appears to give cheap extra horsepower compared to buying a bigger model, and there might be more users taking this route as margins come under greater pressure, particularly in the dairy sector.

How does it work?

There are three main ways of ‘tricking’ the system into what is fundamentally getting more fuel into the engine.

Common rail tuning works by increasing the pressure in the common rail (reservoir) that feeds fuel to the injectors. This type of system is largely only suited to pre-2010 tractors that have basic injectors, as opposed to the high voltage Piezo units fitted to more modern engines. Limitations are largely in the capacity of the fuel pump to supply the increased demand for more fuel.

Injector tuning works by extending the time the injector is pumping fuel into the combustion chamber. Note that a modern injector goes through a number of phases, measured in milliseconds, during the injection phase: pilot, pre-injection, and finally the main injection phases. This type of system works by extending the final of these phases.

ECU (engine control unit) re-mapping seeks to rewrite the software in the main engine controller to effect the increase in fuel in a much more sophisticated manner, and with a much more precise control of power and torque outputs

What are the benefits?

As with any after-market industries there will be professional, and fly-by-night operators. The main theme everyone promotes is power and torque increase from 25% to 35%. There are also claims that although there is a major increase in power, there can be a reduction in fuel consumption which this writer finds difficult to fathom. The suppliers suggest this happens because the extra power means the driver will run at lower engine revs thereby seeing the reduction. I suspect this is wishful thinking as most tractor jockeys use one of two positions – idle or flat out. One company also makes an unsubstantiated claim of increased engine life because the engine runs more efficiently. There is also mention of unlocking 40km/h speed restriction and the opportunity to delete the need for diesel exhaust fluid from modern Tier 4 machines.

The main pros as promoted by suppliers:

• Major increase in power and or torque for low cost
• Reduction in fuel consumption (unsubstantiated)
• Removal of 40km/h limitation
• Deletion of Ad-Blue requirement
• Removal of exhaust gas recirculation (EGR) system.

Remember, modern tractor and engine manufacturers spend a lot of their research budgets ensuring their products perform as they should do. And during the last few years that spending has been huge as everyone has striven to meet ever tighter emission regulations. In many cases this has resulted in systems such as EGR, DPF (diesel particulate filter), DOC (diesel oxidisation catalyst) and Ad-Blue to name a few. The engines of today are far more efficient than those of 10 years, or even five years ago.

Note also that manufacturers supply tractors in a state of tune that is a compromise of performance over economy because of the varied life a modern tractor leads. It might be tedding hay, ploughing or providing PTO power for a large power harrow on the same day.

Are there risks?

The straight answer is ‘yes’. Today’s modern tractor engines, transmissions and final drives are complementary to one another, to ensure they have the ability to deliver the power, and thereby get the work done, and also to ensure a built-in safeguard to handle peak loads and ensure reliability and long service life. 

The internal components of the tractor will vary depending on the power rating, so no surprise that clutch packs may have more plates and might be bigger diameter, and drive shafts might have bigger diameters or carry larger bearing assemblies. This might not be apparent if you stand two tractors from the same product line next to one another. Therefore the introduction of more power or torque might have a devastating effect on a machine’s driveline. By the same token the increase in fuel through the injection system can cause premature failure of these key components.

The key pitfalls:

• Irreparable damage to the ECU
• Might cause the tractor to drop into ‘limp home’ mode as it protects itself
• An over-boost of power with calamitous results
• Major damage to the transmission or drive train
• Safety implications of driving a tractor set up for 40km/h at 50km/h.

So what do the tractor manufacturers say about this practice? Without exception, they believe this course of action is a big no-no.

Mark Hamilton-Manns, NZ manager for John Deere, commented “John Deere’s policy is that warranty is null and void if the ECU is modified. Aftermarket performance specialists will not mention this to customers. JD does not endorse modifying ECUs, nor does it endorse or condone other functions such as ‘deleting SCR’ or ‘deleting EGR’. Our machines are designed for optimum performance and longevity as they leave the dealership. Modifying power and torque will place additional stresses on drivetrains and axles and almost certainly cause failures.”

Peter Scott, national manager for Agco (MF, Fendt and Valtra) tractors made the same comments about the removal of warranty support from machines but also stated “dealerships are increasingly wasting a great amount of time trying to get to the bottom of failures that cannot be attributed to normal use as they seek to support their customer. Eventually they are seeing more cases of tractors that have been ‘chipped’ or modified, and are then put in the unenviable position of telling the customer there is no factory support. This can also lead to problems for the user, particularly contractors, with a loss of reputation which is linked to the tractor brand they operate.”

But the suppliers will say the device is undetectable, in the case of a simple ‘black box’ or that if a re-map of an ECU is detected and subsequently removed and restored with an original map, then they will replace it with their version free of charge. Do they have something they are trying to hide, and why?

A machinery industry source has told Dairy News that some manufacturers now have a feature in their diagnostic software that will remove spurious software from their ECU’s, and then remove the original software also, thus rendering the unit useless. The remedy is to go to the supplier for a new item and a big invoice.

What about the local dealer?

Most dealers will not condone fitting these devices for the above reasons, but appear to be between a rock and a hard place as they seek to preserve the reputation of their brands and keep their customers happy. They accept that users will fit devices to older tractors but will not take any part in the upgrade.

Do I need to inform my Insurer about these mods?

As with any modification the onus is on the user to inform the insurer or risk any claim being rejected. Insurers contacted said they were concerned to hear about companies ‘unlocking’ 40km/h limiters, as tractors that operated at 50km/h normally required front suspension, fixed wheel equipment and in some cases braking systems.

In summary, while ‘chipping’ or ‘re-mapping’ a tractor appears a cheap option compared to buying the right tractor from the manufacturer, such a choice might be counter-productive. If you are spending upwards of $100,000 on a new tractor is it worth the risk of losing a manufacturer’s warranty of perhaps three or four years?

On the flip side, if you have a tractor that is out of warranty it might be an option for a little more get up and go, but it probably makes sense to go the conservative route just in case. Plug-in units bought from the internet would cause this writer some concern, and it would appear that the ‘safe’ route is via an established company that can install and back its products. Whichever route you go make sure the tractor is connected to a dynamometer so you can see exactly what you’re getting, otherwise it’s akin to driving with a blindfold.