Consultation about RPM

Hi,
I wanted to know what the engine is done so that instead of giving about 3500RPM at 100 or 120 km/h, I have about 1200 or 1500rpm.
I saw this in those overhauling type programs or any similar, in which they had a climb and apart from transforming it whole, the engine towards that
or only occurs with giant high performance engines?

Thank you

What you are mentioning me is the task of the gearbox and there enters a factor that you do not mention that it is the torque.

You will see, the engine movement, which rotates at about 3000 rpm by giving an example is unmulting that is, the speed decreases and increases the force with which the mobile parts rotate.

This demultiplication is the work of the gearbox and the differential conical group, so that you get an idea:

ma 3.95/1
1st 3.73/1
2º 2.49/1
3rd 1.67/1
4º 0.99/1
5º 0.85/1
6º 0.75/1

This means that in the reverse, the first, second and third The engine and the transmission (hence the name of direct) and fifth and sixth multiply the movement of the engine, (overdrive)

the first figure is the engine laps, and the second the transmission laps (this is known as the change ratio) in the first, the engine takes three laps and three quarters for a return of the transmission, so the transmission is very slow but with a lot of strength for example while the opposite occurs.

The differential conical group also has a demultiplication, in this fixed case and is responsible for converting and transmitting the movement of the transmission to the wheels, (you will not believe that the wheels turn to 3000 rpm when you go 4th to 3000 rpm)

a greeting.