Quote Originally Posted by aaronng View Post
You need to blip the throttle when you are downshifting, otherwise you wear out the clutch and you defeat the purpose of engine braking, which is to reduce wear.

Also, your "Change into a lower gear which = the engine is working at a higher rate = engine consuming more fuel" is not true. The amount of fuel the engine consumes depends on the amount of air entering the combustion chamber. So if you are at a higher rev but you are not using the accelerator, then you use very little fuel, usually less than having the car in neutral because there is no momentum to keep the engine spinning and it has to open up the throttle a little bit to keep the engine at idle RPM.
to simplify this for those who still don't understand... your throttlebody is still closed as if you were on idle coz your obviously not accelerating... hence acting as a 'brake' for intake air thus slowing the engine down.