In an effort to dispel some of the myths and confusion with regard to which exhaust is quiet or loud, I have come up with some comparative data for NASIOC users. This may help indivduals who live in remote areas or areas where few different exhausts are located to determine which exhaust is right for them.
a. All measurement are and will be taken with an Exetech digital dB meter with an accuracy of plus or minus 2db using the same settings at the same distance.
b. All idle measurements are taken at warm idle, NOT cold (higher RPM) idle, and then 3000RPM.
c. All measurements are taken 6" from the tailpipe.
d. All measurements are averaged, not peak high or peak low as the exhaust dB can vary 5-10dB due to the boxer motor characteristics.
Today I measured a 100% stock 2002 WRX to "zero" my meter with the previous testing results of Turbo & High Tech Performance Magazine's data
. Their data has been used as well to broaden the information as they tested some unique exhausts.
With every Subaru Meet I go to, I will bring the dB meter with me and do testing. I will bump this thread with each addition.
I won't post the results here as the bulletin board's software screws up all the cool formating, but you can download it from my server via these two links:
(MS Excel format) 31 kB
(the format will be messed up slightly) 8 kB
Exhausts tested so far:
APS 3" & 3.5"
Borla (XR-1 and Hush)
Greddy (EVO and SP2)
Heyward and Scott
HKS (Hi-Power and Carbon Ti)
Stromung (single and dual tip)
Thermal Research & Development
TurboXS (Magnaflow & RFL)