(sorry, this is in English)
I start this thread to discuss about two divergent opinions regarding the relationship between NOACK oil volatility (evoporation) and intake valve deposits on gasoline direct injection engines.
The main (which is also the intuitive) opinion is that an engine oil with a lower NOACK evaporates less, therefore there will be less deposits on the intake valves.
However, there's the other (opposite) opinion, stating that intake valve deposits are not actually caused by the oil vapors (gas), but by the oil droplets (liquid) that escape the positive crankcase ventilation (PCV) system. According to this theory, the lower the NOACK, the more time the liquid droplets spend on the intake valves (due to slower evaporation), thus giving enough time to the oil components and contaminants within the droplets to deposit on the valves. Going ahead with this logic, it means that in order to reduce the intake valve deposits it is best to use the oil with the highest NOACK and lowest SAPS. It may be counter-intuitive, but I must admit that it does make sense.
What is your point of view on this subject?