A chip in your engine

Technically speaking, the most common operation in tuning is to increase engine power. Child's play, requiring no particular knowledge or technical skills thanks to electronics. But is this practice really safe?

English translation - original article published in French by Federauto Magazine

In the past, "boosting" an engine meant making numerous technical modifications, which were at the time the preserve of certain specialized tuners. They would increase the number of carburetors, install "big valves," "aggressive" camshafts, "4-into-1" exhausts, etc. Expensive and mostly irreversible, these mechanical "improvements" also considerably modified the engine's character, with high-RPM power gains coming at the expense of torque and availability at low rotation speeds, not to mention consumption and even less pollution emissions.
Today, while the desire to increase one's machine's performance is still there, it no longer requires any disassembly or mechanical modification. Because in an era where engine operation is completely governed by electronics, it's enough to modify a few parameters to see power and torque figures soar. We're talking of course about tuning boxes reserved in most cases for turbodiesel engines. From unofficial sources, more than 900 box-units of this type are sold each month in Belgium.

How does it work?

Concretely, the tuning box is installed between the original ECU and the injection system. The box-unit intercepts the original signals and reinterprets them to adapt the injection duration in a few microseconds, if necessary. Because if no power need is felt, the engine operates according to the settings initially planned by the manufacturer. A good performance chip therefore doesn't completely override the stock ECU which always remains in control of parameters such as regulation speed (injection cutoff from a certain RPM), boost pressure management or pilot injection triggering. All vital parameters for mechanical longevity and proper operation. Note also that in case of box-unit failure, the engine's electronic management automatically returns to original configuration. We met with Philippe Heeren, managing director of P.Tronic, a company specialized for 8 years in the distribution and development of tuning boxes for turbodiesel engines.
"Our development philosophy consists of improving driving pleasure by offering more torque at low RPM, while always respecting manufacturers' tolerances. But our great strength is providing original connectors, requiring no tools and no disassembly."
And Philippe Heeren follows words with action by handing us a chip to install under the hood of our test car. Indeed, in no time at all, the installation is done, without even getting our hands dirty.

The dyno verdict

Measured at 113 hp at 3,820 rpm and 292 Nm at 1,950 rpm in its original configuration, our test car, once equipped with the famous box-unit, sees its power and torque characteristics rise to 131 hp at 3,200 rpm and 354 Nm at 2,330 rpm. The most interesting part, however, remains the curve plots.
"You'll notice that at equal RPM, with the chip, you always have more torque and power," Philippe Heeren points out.
In fact, the original plots are practically preserved, but have been shifted upward, which improves acceleration and pick-up, without however modifying top speed.
"It's still possible to do better," the development manager confides, "but at the expense of consumption and pollution emissions. In their standard configuration, our performance chips always remain within the limits of the pollution standards that the stock engine meets."

Use in moderation

Assuming that consumption, pollution emissions and engine longevity are not threatened by installing a tuning box (provided only injection duration is modified, and within certain limits), one can however wonder about transmission components, subjected to significantly higher stresses than those for which they were initially designed.
"All components of a vehicle are part of a whole whose balance risks being disturbed by modifying one parameter or another," reminds Filip Nolf (Citroën Belux). "And this especially applies to transmission components."
Therefore avoid repeated wheel-spinning starts or sudden accelerations with wheels turned if your car is equipped with a "power kit." That said, no importer has reported any particular problem related to installing a box-unit. Are "traces" of modifications systematically erased before going to the dealer? It's likely, especially since warranty contracts stipulate that any modification causing a breakdown or mechanical damage voids the manufacturer's coverage.

"Factory" tuning

Modifying engine electronic management parameters isn't only the preserve of modern "tuners." Under cover (sometimes) of different names, some manufacturers thus expand their range of engines or simply announce the arrival of a "new" engine. Thus, between a Mercedes C 200 CDI and a C 220 CDI, only the ECU programming is different. This is also the case at Volvo (the D5 and 2.4D engines are mechanically identical) or at Mazda whose 6 is offered in two power levels, only by adjusting management programming.

Power increase: three techniques

Besides installing a tuning box as described in this article, there are other methods to electronically increase engine power. One can replace the original chip with a modified one or reprogram the original ECU via the diagnostic port. This last solution, while having the advantage of not having to open the box and being invisible, may however come at the expense of driving pleasure: the base ECU is indeed configured to offer an ideal compromise between smoothness and power, while taking into account consumption and pollution aspects.

Intake and exhaust kits

Tuning magazines are full of advertising touting the merits of intake kits and other special exhaust systems. A basic mechanical tuning element, the special exhaust system alone cannot ensure a power increase. This requires a complete replacement of the exhaust line and manifold, which means a significantly more substantial investment. The only "reasons for being" of a modified exhaust are therefore primarily aesthetic, but also sonic. This is also the case with intake kits which, besides their look, allow the engine to "roar" more noticeably. Some air filter cartridges can be washed with water, which guarantees maximum efficiency and low operating cost, but what about their "protective" effectiveness?