What's your average speed? that's the key indicator. I only average 32km/h as I drive mainly during peak hours in the NE surburbs of melbourne and I get 15l/per 100 thanks going gentle ish! If I use the boost it's into the 18's but on the freeway going it will do less than 10 l/per 100 kms if I was going for a long cruise. If you're getting 400 from a tank it's not too bad for traffic conditions