One of the most intriguing changes in the technical regulations for 2018 is related to engine plenum air temperature monitoring, suggesting that the engine constructors had previously cooled the air in that place to get more performance out of the engine.
FIA has decided to further clear certain parts of the regulations to prevent the use of gray zones and mutual interrogation of engine manufacturers.
Article 5.6.8 of the Technical regulations says the air at the inlet of the cylinder must be more than 10 degrees Celsius warmer than the ambient air. The temperature will be measured as the average value in a single lap using a special sensor prescribed by the FIA.
The FIA wants to keep an eye of what is going on with the cylinder inlet temperature because it is clear that some manufacturers have used cooler air to feed the engine with cooler air and have better performance.
The cooler air has more oxygen in the same volume, which means that the turbine has to spin less to produce the same power, or can produce greater power if it is already working on maximum allowed speed of 125 000 rpm.
Now that the air needs to be warmer than the outside temperature, besides the potential loss of power due to less oxygen, the turbine temperature may also increase, which results in a reduction in power and efficiency.
FIA prohibited alternative use of recycling fluids
New Article 5.1.12 states that all liquids in the power unit can only come into the atmosphere and must pass through the opening at the back. Liquids must not be returned to the power unit.
This suggests that engine manufacturers used such fluids to get extra power from the engine from their combustion.
More strict oil burn limits
The FIA has even tightened the maximum permitted amount of oil that the engines can use so far, so all the specifications introduced by the 2017 Italian GP had to comply with 0.9 liters of oil per 100 km limit (before it was 1.2 l/100 km) and this year the limit has dropped to 0.6 liters per 100 km.
Also, the teams may only use one fuel and oil specification during race weekend to prevent them from using specific specifications in the qualifying and the race.
The definition of the oil itself became more strict to ensure that the constructors use it only for lubrication, cleaning and cooling rather than for combustion to create extra power.