View Single Post
Old 02-09-2009, 03:22 PM   #7
SkurdalenFox
Senior Member
 
SkurdalenFox's Avatar
 
Join Date: Sep 2005
Location: Boulder, CO
Posts: 463
Basic formula is: speed of sound = wavelength * frequency, which means

wavelength = (speed)/(frequency)

Quarter wavelength = wavelength/4 (as one would guess)

Speed of sound is from

http://www.sengpielaudio.com/calculator-speedsound.htm

(obtain speed from deg F, and in ft/sec)

Engine speed of revolution given as 2000 rev per min which (when divided by 60 sec/min) is 33.33 rev/sec

Firing frequency = (Number of cylinders)/2(four cycle engine) with V8 = 4

So exhaust fundamental frequency is 33.33 * 4 = 133.33 or about 134 Hz

So quarter wavelength = (1520(speed in ft/sec)/134) * (12"/ft) / 4 = 34", for 500 deg F at 2000 rev/min.


I'm just guessing at the EGT. Anyone have a better guess? I was thinking of putting the tubes after the mufflers. Car is a five liter 92, no cats.
__________________
Jim
SkurdalenFox is offline   Reply With Quote