The tachometer helps use engine power and save fuel. It doesn't cost much, and assembly is not difficult. A car tachometer is not a very complicated device. If we feel adventurous and know a little about electronics, we can even make it ourselves. Automotive accessory stores have tachometers ready to be mounted on the instrument panel. It can be a device showing the rotational speed on a display in the form of a line of light with LED diodes or as an indication of a tilt meter. The information given by the first one is read intuitively, based on the number and color of the lit LEDs. The second one will introduce a raw atmosphere to the interior of the car, sporty style.

Installation
Mechanical fastening should not be a problem even for novice DIY enthusiasts. The electrical installation is much more complicated. We have to find it in the engine compartment, on the terminals of the ignition coil, appropriate cable, thanks to which our tachometer will receive information about the ignition frequency, and therefore the rotation of the crankshaft. If we don't feel up to it, to do it yourself, we can ask a car electrician for help. The service of connecting the tachometer should cost from approx. 50 zloty.
Depending on the version selected, the tachometer can be built into the instrument panel, in a special console or also, if it has its own housing, mount it in a clearly visible place on the instrument panel. It would be optimal, if it were close to the main indicators, primarily a speedometer.
By installing our tachometer, we first had to make a hole in the instrument panel for the kickstand, where all the wires pass. The wire responsible for illuminating the scale is connected to the combined light switch, so that when the vehicle's parking lamps are turned on, the scale of the device has also been highlighted. To make it possible, to the mass (minus) vehicle, we also need to connect the second wire from the tachometer. The third wire is connected to the power plus. The most important, the fourth wire must be led to the engine compartment and connected to the signal source in the ignition coil. This solution is possible in traditionally constructed cars, where the ignition coil is located outside the engine and is physically accessible. Otherwise, it is best to seek help from service personnel.
The source of the signal used to measure the rotational speed are electrical impulses from the ignition system. These pulses are converted into direct current, in proportion to their frequency, and then measured with a magnetoelectric meter. Since the frequency of the pulses depends on the type of engine and the number of cylinders, we still need to make the appropriate switches in the tachometer (e.g. using jumpers), which are fully described in the tachometer installation instructions.
After connecting, and before finally screwing on the tachometer, it remains to be checked, is everything working properly.