<p>The VAF must go just before the TB. <p>If you meter air that gets blown off after the VAF by putting it before the turbo, you will never get the thing to run right under any load at all because the VAF/ECU are so sensitive.In either position, it is useless once the airflow exceeds the amount the engine can injest by itself, anyway.
If you put it just before the TB, it will max out as soon as you exceed the maximum engine flow when stock - just after you see ANY boost.
However, if you put it before the turbo, it will max out as soon as the combined amount of the engines intake and the turbo's output exceed that same amount (an amount that is dependant on the flow characteristics of the turbo system itself) which will be acheived at a very low throttle positon under load. <p>Blowing hot, compressed air past the VAF isn't too much of an issue - I consider the VAF a "wear" item, anyway and I have yet to toast one.
