The recent discussion on looking for improvements for the GXP airbox got me thinking about using a more scientific method for locating bottlenecks in the inlet tract. My thought is that taking vacuum / pressure measurements at various points in the inlet tract might help to identify the areas with the most potential for improvement.

It seems to me this could work for N/A or boosted applications – for NA you’d be watching vacuum readings, on boosted apps you’d be looking for a drop in boost pressure.

For example, if a vacuum reading on a GXP (N/A) was taken between the airbox and the MAF, and the vacuum reading was very low, my thought is that there would not be much to be gained with airbox mods. Of course this would require taking the vacuum reading on a WOT pull to redline. Then next place to check might be immediately after the MAF to see if the MAF is a significant restriction.

Something like this might be helpful with tapping into inlet tubes or plastic airboxes.

One concern I with this method is getting an accurate reading. I have to wonder if the air velocity inside the intake tract might cause an inaccurate reading.

Any thoughts? Has anyone done this or heard of it being done?