More power in the wet

[peter.vw]

Has any one noticed an improvement in performance when driving into the rain or damp air or is it only me.
Its been long debated that a car will run better on a damp night.
The scientific reason being that the damp air being drawn in to the engine will expand when burnt with the fuel in the cylinder creating greater mass over the piston.

[Richc69]

Cold damp air is more dense, so you get a better cylinder charge on a n/a engine. Not sure the effect is so marked on a turbo. But yes most of my petrol cars have always seemed to go better in damp cold conditions, other than my classic mini which must have automotive rhumatism

[RW1]

The prescence of water increases the mass flow. The injection water into the engine inlet reduces the air temperature, thus increasing the air density and the consequent additional power.

Commonly used practice in injecting aero turbine engines to increase the shaft horse power during take-off or when operating from hot, dry & high altitude airfields. Methanol is added as an anti-icing agent (as well as being an additional source of fuel) when doing by artificial means when upping the power of an engine. In practise we could get a 1,835 shaft h.p, engine up to 2,040 s.h.p. by water/methanol injection. A quick sum is 11% power increase.

So not surprising the Scirocco's engine will run better in damp air, particularly as the supercharger and/or turbo boost is used.

C.