Often you hear farmers and contractors talking about the new tractor being a little disappointing in terms of power and fuel at the start of its life. Is this true or is it a misconception?

To look at this, and give an actual figure, Billy Shaw agreed to a power test on a New Holland T7.200. The tractors used were identical models with identical specification. The only difference is was the amount of engine hours.

The test did prove that the perception is indeed reality. The tractor with more engine hours gave a higher horsepower result on the dynamometer, with an increase of 6hp over the tractor that had only five hours on the clock. The engine on this tractor is an FPT 6.7 litre complying with the tier 4a emissions regulations. These engines boost under certain conditions – to increase power when driving powered equipment, or on the road over the recommended speed. For the purpose of the test we turned on the boost mode on the engine to measure the increase in power. Both engines increased by 28hp irrespective of the hours on the engine. The service interval on the T7.200 is 600 hours.

These engines have a rated power of 155hp and a rated boost figure of 190hp. However, in reality the T7.200 is a 155hp tractor and not a 190hp tractor. The maximum power achievable under boost on a bench-tested engine is 203hp according to the New Holland specification. In many ways this why operators may feel disappointed with the power, expecting boosted performance levels from the moment the engine is turned on. If ploughing with a straight 200hp tractor, you will have this power always available regardless of the forward speed and PTO load on the tractor. The disadvantage is that you always have a tractor using the fuel of a 200hp tractor.

The other part of this test looked at an engine’s performance as the years and the hours pile on. To look at this, we tested two more tractors in the yard. The first tractor tested was the first of the T6080 New Holland series. This tractor had an EGR system to satisfy the emissions limits in 2008 as was the case with nearly all models of that era.

The tractor was not serviced and had 5,500 hours on the clock. The tractor delivered 148hp, which was under the rated power for that model by 7hp. Turning on the boost function on this tractor increased the power by 10hp only. The results from this dynamometer test indicate that this tractor is due a comprehensive service. We fitted the tractor with a new air filter, which increased the performance by 2hp. There may also be a need to examine some of the sensors and data from the tractor’s ECU.

The last tractor tested was the very popular TM 155. The tractor had worked 10,500 hours with a 2003 registration. This tractor has a six-cylinder 7.5 litre engine with a rotary fuel pump.

The tractor was described as straight off the farm and only arrived in the yard. The dynamometer revealed to us that this tractor is still very capable, delivering 165hp at 1,000rpm on the PTO shaft. This is up on the rated power of 155hp by 10hp. Indeed, the maximum power on this tractor was 170hp. The noticeable difference from the new models was the plume of black smoke as the engine was fully loaded. The torque reserve on this TM is lower at 35% versus 51% on the T7.200 tested.

So it is true a tractor’s engine will improve with age like a fine wine. But the engine will only give that performance if the servicing is maintained on the correct schedule. Even a new tractor that is due a service could give a dip in performance, which has nothing to do with the number of hours on the engine. A farmer should buy a tractor with the opinion that if 200hp is needed all day long, an engine that boosts to 200hp from 155hp may not give that performance.