Theoretically, the Evo does hold more than 5 quarts. However, with an oil change you can't comfortably fit more than 5 because the oil cooler always hides a little. When you change the oil, you aren't getting the oiling system completely dry. If the entire oiling system was completely drained out, you could probably fit a little over 5 quarts.

5 quarts isn't abnormal even for a four cylinder. More oil means cooler oil. Less oil heats up faster, especially when you're cooling a turbo too.

 

Thanks for all the help and clarafication everyone.

 

oil cooler volume