Exhaust muffler testing

Here are some exhaust muffler tests done by various people or magazines.
Some interesting reads.

http://www.gusmahon.org/html/mufflers.htm
http://www.pontiacstreetperformance.com/psp/exhaust.html
http://autospeed.com/cms/A_0383/article.html?popularArticle

Some charts;

I’ve enchanced the above chart to make it easier to read. Not sure if the RPM-numbers are correct above but that’s kinda moot IMO.

Once found on GeoCities.com (Not online anymore):

Click image for larger version