[Howard Jones]

I think that one thing that has been missed, or at least I missed it, so far is that even if the restriction caused by the screen is 50% you can still flow 100% by increasing the screen area by double.

This can be done by making the opening in the screen through which the air must flow bigger and shaping it like half of a ball much like the set on the DFV seen above in this thread.

The worst case is a flat screen stretched across the top of the trumpet. Some of the strainers used must be at least 50% restrictive and likely much more so. Not to say that they don't work somewhat to keep out large pebbles but they certainly don't do anything to prevent engine wear due to ingesting dust.

As far as how long they might reduce engine life. Consider a trip of 100 miles down the freeway. Nice clean air, no dirt in the air etc. As you arrive at your destination you must turn off the highway onto a less traveled road and at one point cross a few yards of dusty road left by a homeowner digging a new planter.

Those few seconds of dusty road will produce more wear than the previous 100 miles.

I know they really look good, I love the look of a set of Weber's with velocity stacks on them but a good quality air filer is the way to go.

Somebody a couple of years ago had a clear box with filters elements in the sides of it covering up a 8 stack setup. Very good idea. A oval turkey pan with a clear top and sides made of filter material would also work very well. Much less restrictive also. If I ever can afford a set of Webers thats what I'm gonna do.