but isnt that bad....
Cars run best, and have the most power at 'optimum' running temperature, so you are loosing power if you're motor can't warm up. so long as the car doesn't exceed its optimum temperature you can block off all you want. Think about how my honda has a half-size radiator but still only gets 1/4th the way up on crazy days like this. Its not any more 'advanced' of a design than a full-size radiator, my motor just doesn't need that much cooling.