quote:
"High-speed, long distance driving," by European standards, likely means several tens of miles at speeds above 100 mph. The power required to overcome atmospheric drag at 130 mph (most Audi's governed top-speed) is more than twice that required at 100 mph. The result of this is that at any average speed of less than 100 mph, your engine is under only half the load and is probably producing less than half the heat that Audi felt necessitated a 5W-40 oil. Driving at 75 mph in an Audi requires only about 25 hp, and does not heavily load the engine. Your engine is likely more than well protected with an API SJ 5W-30 if you drive mainly on public roads, and do not average speeds greater than 100 mph over distances greater than a few tens of miles. Short sprints up to 130, if you are fortunate enough to live where that is possible, should not cause a problem. Only sustained high-speeds heat the oil enough to significantly reduce viscosity.