#How to improve engine response

27 / May 2024
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How to improve engine response

Seletron Performance

How Engine Response Affects Driving and How to Improve It

In almost all articles discussing electronic tuning of cars, whether they run on gasoline or diesel, there is a general tendency to focus heavily on the (absolutely important) aspect of increasing power values in horsepower or kilowatts (kW) and torque in Newton meters (Nm). We have repeatedly emphasized the issue of engine response and will later discuss some interesting solutions, but first, we want to talk briefly about how this parameter (which doesn't have a real technical reference) impacts the driving pleasure of the car.

How Engine Response Can Change with the Same Torque

Every car engine has the classic parameters that we all always read in specialized magazines. These include the power value expressed in kW and HP, the maximum torque value, and the two values that specify at what RPM these two parameters are expressed, namely the RPM for maximum power (which is not the maximum rotation speed) and the RPM for maximum torque (which in some cases has a range rather than a single peak, e.g., "from 1800 to 2400 RPM").

Rarely, maybe during engine tuning discussions, a graph might be published that not only shows the maximum values mentioned but also the two curves of torque and power delivery. Looking at these graphs, at least for the more informed, means understanding at a glance what kind of delivery the engine has based on the RPM. For instance, we can understand if the engine is flexible, has a certain linearity, has a good propensity to "stretch" at high RPM, and other things. However, what the graph does not tell is the engine's response to driver commands, a factor that significantly affects driving pleasure unless it is purely about racing where the engine is almost always in torque and at mid-high RPM, and where maximum values and power-to-weight ratio mainly matter.

To understand this better, we can look at a technical sheet of a turbo-diesel or turbo-gasoline engine and see that the maximum torque is expressed (just as an example) at 1600 RPM. Let's also assume we have a medium-sized car with a maximum torque of 350 Nm, a value surely capable of providing good thrust. Even looking at the graph, one would be led to think that pressing the accelerator near 1600 RPM would provide a powerful and immediate thrust of about 350 Nm... not necessarily true!

The maximum torque value expressed at that RPM indicates that the engine, already under load, can deliver these crucial 350 Nm, but it does not mean that pressing the accelerator after a release phase will result in a thrust of 350 Nm on the car's mass. Particularly when talking about a turbocharged engine (as in this case), the time between pressing the accelerator and the actual torque delivery can be several tenths of a second, a second, or - in engines with higher specific power and a single traditional turbocharger - even a few seconds!

Indeed, there are engines that on paper have the peak maximum torque at a very low RPM (thanks to twin-scroll turbochargers, turbo-gasoline engines can have maximum torque at very low RPM, even lower than turbo-diesels). Still, in practice, when driving, they are very sluggish until they reach a slightly higher RPM. An example among all? Just think of the 2-liter turbo-gasoline 4-cylinder engine from Mercedes in one of its less powerful versions; the 211 horsepower one (the 2-liter turbo Mercedes can reach over 400 hp in the sportier versions) which has a maximum torque value at just 1200 RPM, when even a turbo-diesel rarely has maximum torque below 1400 RPM. This engine, if kept in torque, can indeed push with all its force already at 1200 RPM, but if you floor the accelerator at this RPM, you don't feel the maximum thrust at all; you have to wait a moment for the engine to start revving a bit more to have a ready response.

So, we are beginning to understand how engine response can significantly affect driving pleasure. In turbocharged engines, the inertia of the turbocharger is a determining factor in response times to accelerator commands, but the software in the engine control unit also affects this aspect. What we know is that when driving with constant speed and acceleration variations, it is very pleasant to feel the engine ready to meet our power demands. Elements such as variable geometry turbos, twin-scroll turbos, variable geometry intake manifolds, variable valve timing, significantly contribute to making the engine more responsive, but electronics also play an important role.

What Can Be Done to Improve Engine Response and Thus Driving Satisfaction?

Certainly, our performance kits, designed to increase power and torque and consequently performance, positively impact engine response, at least at certain RPMs. However, if you are not interested in increasing horsepower and Nm, you can quickly and without any modifications install the electronic module for the accelerator pedal. This Plug&Play device acts on the signals from the accelerator pedal position sensor and can be set to various levels of sensitivity increase. In the CONNECT versions, you can even control the engine response from your smartphone via a specific app.

The electronic accelerator pedal module makes the engine more responsive and ready at all RPMs without increasing power and torque (if you also want to increase performance by increasing horsepower and torque, you can also install our CHIPBOX digital additional control unit), offering a completely new driving pleasure.

For more details on how it works and how the accelerator pedal module can be set, you can click here > PedalBooster CONNECT, while if you want to see all the electronic tuning options for your gasoline, diesel, or hybrid car, click here and select your exact model