Need some info. Ok, four valves per cylinder is better than two valves per cylinder. Fine, why did Ford REVERT to only 3 valves (my guess is to save cost SOHC)? Audi and VW are using five valves per cylinder on some cars, does this offer any advantage over a four valve engine? Maserati even experimented with a six valve per cylinder!!!! (see link) http://www.maserati-alfieri .uk/alfier... but abandoned it (my guess is cost again?) Why are we stuck at four valves or would more valves actually render more horsepower? Pop some ideas best answer to reasonable answer...
Think of an engine as an air pump - obviously, we want the least amount of restriction for the incoming air and also the least amount for exhausting the compressed air. The ideal situation would be to remove the head during the intake stroke and put it back on during the compression stroke, but, obviously, this isn't possible. On a naturally aspirated engine, the intake is the most critical because the air is moved only by a relatively small difference in pressures. The exhaust stroke, on the other hand, is aided greatly by the super heated temperature and rapid expansion of the gasses. Two intake and one exhaust valve seems to be the most practical and efficient solution - adding more vales means smaller valves and an increase in the overall complexity. I seriously doubt that Maserati ever abandoned ANY automotive idea due to cost restraints. It's far more likely that adding more valves than three or four simply resulted in diminishing returns. Sometimes the allure of a new buzz phrase is nothing more than a marketing ploy - a 16 valve, DOHC, four cylinder engine, for example, is a pretty impressive resume for an engine, regardless of whether it actually is the optimum performance set up or not.
