Changing where a tractor’s peak power is available is becoming a popular option for farmers looking to trim fuel costs when running certain implements that don’t require PTO power.
New tractors are set up to operate safely in any condition, which means they might not be running at peak efficiency for certain tasks. This can lead to operators feeling a new machine is underpowered compared to a previous model. The lack of an exhaust note, along with ever stringent emissions technology, contribute to new tractors feeling a little lacking.
It is a common reason for users turning to professional engine remapping to better match tractor power to certain applications or implements. This isn’t necessarily about increasing top end power, but changing the power and torque delivery in the mid-range to offer peak power at a lower rpm.
Gareth Jones from Avon Tuning says for jobs that don’t require a PTO, such as cultivations and haulage work, this is returning some real-world fuel savings by increasing the efficiency of the application. “If a tractor achieves peak power at 2,000rpm, it must always be revving near its limit to achieve it. By changing certain parameters in the ECU, we can bring the peak power delivery to 1,600rpm, meaning the tractor doesn’t have to work as hard.”
Mid-range power
The changes to mid-range power has benefits for tractors on haulage work and heavy lugging, as the engine can access peak power lower, so there is less requirement to rev high in each gear.
If the implement is on the limit of the tractor’s current capabilities, it will always be working hard to achieve peak power. “Typically, tractor outputs are set very conservatively so they can function in any environment that is thrown at them. The engines are capable of the power, but tuned down to be very risk averse,” says Mr Jones.
However, by matching output to certain applications, Avon can safely improve performance within the engine’s capabilities. When applying an economy specific remap, Avon only adjust key parameters such as fuel injection and torque limitation in the mid and low range, therefore top-end rpm performance is not changed.
Modifying these characteristics allow operators to run in a higher gear at lower revs to benefit from the additional low-down peak power. This is noticed when ploughing or cultivating, especially if the implement has made the tractor work consistently at its limit before a remap. “Fuel savings of between 5% and 10% are achievable in some situations,” says Mr Jones.
Before applying any remap, the tractor’s characteristics are cross-referenced to make sure any increase in power can be handled by all the component parts. “If we spot anything that could prematurely fail due to a power increase, we will advise the customer against a remap. Over torquing an engine is more dangerous than over revving, with the potential to break shafts and transmissions, so understanding the whole running gear setup is critical.”
A good example is New Holland’s Tier4 T6.180 tractor and full T7 range, which all use the FPT 6.7-litre, six-cylinder engine. This could lead some to believe the potential power increases are the same, regardless of the model, however, the T6 has a much smaller back end and is the limiting factor when it comes to any power changes.
CVT gearboxes
Although a power shift gearbox puts the control in the hands of the operator regarding when to shift up or down to manage where peak power is most available, there are very similar benefits to tractors running CVT transmissions.
Editing software is the same and the automatic transmissions can adapt to where the power is available. “CVT gearboxes are highly sophisticated and will intelligently monitor the load being exerted on the engine and how much torque is available. It then changes gear to suit the task at hand and will adapt to the power adjustments.”
Automatic transmissions are very popular in tractors and being able to change where they access peak power and torque will mean they aren’t having to work as hard to achieve the same output. “Revving an engine near its peak rpm consistently would add additional stress to it, so being able to use more torque at a lower rpm could reduce this, however to avoid adding pressure to component parts, such as the gearbox, getting the right balancing act requires experience to maintain reliability,” explains Mr Jones.
Case study
Yorkshire contractor saves 3l/hr on haulage work
Chris Rodgers had a remap installed on his 2010 Claas Axion 810, taking power from 203hp up to 241hp and a torque increase from 1,603Nm to 1,908Nm, measured at the PTO, and while the extra power was noticeable, it was the power delivery at the mid-range point that has helped reduce fuel consumption by 3l/hr.
After Mr Rodgers bought the tractor, he found he was using a lot of revs to get the most from the engine when hauling grain, grass and straw, which makes up the majority of his work.
“I’m using around 3l/hr less fuel than I was beforehand when I’m hauling trailers. My fuel bill has reduced and I’m putting in less diesel every evening. I also charge some jobs on price per litre, so my customers are making a saving as well.
“Before the remap, some of the hills that I had to drop down four or five gears in the past to get up, I now only need to drop two, and wouldn’t be taking the revs up to the usual level.”
It has allowed Mr Rodgers to tailor his current machinery to better suit his workload. However, he is an advocate of testing tractor output on a dyno before a remap is added. “I think it is essential to know your tractor’s output before any work is done, as the repercussions of remapping a poorly engine could be costly,” adds Mr Rodgers.
Insurer’s view – NFU Mutual
“For farmers looking to increase horsepower and improve fuel consumption, it’s important there isn’t a risk of exceeding the limits of the machine and reducing its lifespan. If you are working a machine harder, you must service and maintain it more regularly and so it’s vital to take that into consideration.
“It’s also worth checking your insurance policy and letting your insurer know about significant modifications. Under the general conditions of your insurance policy, you may be required to tell your insurers if any vehicle on your policy is modified in any way. In terms of how it would affect insurance, it would depend on the circumstances and your insurer would want to understand the reason for the change.”