I would like an explanation of automobile exhaust pressure waveforms.?

Question

I have seen exhaust pressure waveforms on a cold test machine and would like to know what the various parts of the curve represent and what specific deviations from the norm would look like.

Answer 1

http://forums.vwvortex.com/zerothread?id=2144780
http://www.lcengineering.com/TechNotes/TechNote68.htm
http://www.powerflowsystems.com/newData.htm
Your question would be best answered by an Engineer, however there is some good info at these sites if you are interested in reading up on it.