Preheat your oven to 325°F (160°C).
In a large mixing bowl, combine flour, sugar, baking powder, and salt.
In another bowl, whisk together egg yolks, vegetable oil, water, and vanilla extract.
Gradually add the wet ingredients to the dry ingredients, mixing until smooth.
In a separate bowl, beat the egg whites with cream of tartar until stiff peaks form.
Gently fold the egg whites into the batter in three additions.
Pour the batter into an ungreased chiffon cake pan.
Bake for 50 minutes, or until a toothpick inserted comes out clean.
Invert the pan immediately after removing from the oven to cool completely.
Once cooled, carefully remove the cake from the pan and dust with powdered sugar.