Quote:
Originally Posted by Isaac Zackary
The goal has generally been to sync the intake going in for years with tube length and width in order to improve performance. But I understand that Porsche is doing the opposite and is getting better fuel mileage results due to cooling of the intake charge (air cools as you stretch it). Which in combination of a turbocharger still allows for a better intake charge than a normal engine. In other words, it's compressed by the turbocharger then stretched back out through harmonics in order to cool the intake without using a restrictive source like a throttle valve for each intake runner. This allows for greater boost, lower NOx emissions and better power and fuel mileage.
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Boyle’s law tells us that if pressure in a gas is increased then temp increases (I can’t remember the ratio) and it cools as pressure is reduced so ‘stretching’ air - which I assume means reducing its pressure and therfore density would cool it back to the starting temp. You can’t (I’m pretty sure physics won’t let you) keep the higher pressure from the turbo and let the temp drop without somewhere for the heat energy to go like an intercooler.