An international long-haul tractor unit covers 120,000 or 150,000 km a year, almost all motorway, loaded close to 40 tonnes and crossing mountain passes with the trailer full. There, fuel is half the running cost, and every litre per 100 km is multiplied across the whole fleet and the whole year. When a company brings a truck in to be remapped, they are not after more speed, they want the engine to hold top gear up a grade without changing down, to pull from low down fully loaded, and to use a little less on the road. A custom remap tunes exactly that, without touching the emissions system.
On long haul the truck spends almost all its time at cruising speed, between 1,100 and 1,400 rpm, where the engine has to move 40 tonnes for the least fuel possible. A custom remap fine-tunes the torque delivery in that band, so the engine holds the speed with less throttle and fewer downshifts. On a 480 hp tractor we work the low-rev torque more than the peak power, and on flat motorway with a steady driver fuel use drops by around 4 to 7%. It sounds small, but over 130,000 km a year that is thousands of litres per truck.
The moment that punishes a long-haul truck most is a mountain pass at full load. As standard, the engine runs out of breath and the driver has to keep dropping gears until stuck high in the rev range, burning more and going slower. With more torque available at 1,100-1,300 rpm the truck holds a taller gear on the climb, changes down fewer times and crosses the pass at a steadier pace. That shows up in route time and in transmission wear, which suffers with every forced downshift. We set the torque to what the gearbox and clutch take with margin.
A truck running across the whole of Europe cannot afford breakdowns far from home, so reliability comes before horsepower. That is why we stay conservative: we set the torque within what the engine and transmission take in continuous use, not at bench maximum. We do not touch the AdBlue, the EGR or the DPF, because disabling them is illegal and many European countries run roadside emissions checks with heavy fines and the risk of immobilising the truck. We always save the original map to put it back before an official service or a roadworthiness test.
On motorway routes with a steady driver, fuel use drops by around 4 to 7%. It sounds small, but on a truck doing 130,000 km a year that is thousands of litres. The saving comes from the low-rev torque, which lets the engine hold its gear with less throttle and fewer downshifts.
Yes, if it is done custom and conservatively. We set the torque to what the engine and transmission take in continuous use, not at theoretical maximum, because a long-haul truck cannot afford breakdowns far from home. Reliability comes before horsepower.
Yes, and that is how we always do it. We do not disable the AdBlue, the EGR or the DPF: it is illegal and many European countries run roadside emissions checks with heavy fines. A custom remap works the torque and response without touching the emissions system.
If the truck is under manufacturer warranty, a remap can affect it; we save the original map to put it back before an official service. As we do not touch the emissions system, the truck passes its roadworthiness test normally.