running mac eaqual length headers, flowmaster 2.5 kit all the way back to drops. drones like crazy, want to swap mufflers to spintech . heard they dont drone. is this true ??
Here's the text of Jerry's comments, unfortunately, the pictures of the mod have long since disappeared...
jerry beach said:
I have seen constant threads here over the years on how to stop the drone. Most want good sound without the annoying drone at a steady speed. This is a pic of the underside of a 2003 GT with 1 chamber flows installed.
This view is from right behind the passenger rear tire, up on front of the gas tank. I have a panhard bar, so I would have to get creative on installing this in my car. The pipes should be 1/2 the length of the tailpipes after the muffler. You can see they are smashed and welded shut on the ends. The noise enters the chambers and returns to the opening canceling the next noise. So you can run a race muffler, get the benifits of flow, and not give away the fact that you are doing so.
The reverb and echos were insane before the installation of these noise cancelling pipes. Now you can hear a noticably deeper and louder tone at idle, and you can hear it good at WOT but exhaust noise at cruising speed is gone. There is a little blip at 1900 rpms and at 2900 rpm, but if you dont stay there its quiet. I will post some better pics when its jacked up tomorrow to change the springs. Its really simple and the local muffler shop charged him $60 to do this mod.
Your chart is quite interesting and informative. My observations are that the drone starts about 1700 RPM and stops about 2300 RPM, and that a 2 /14" exhaust system is more noisy at 1700 than a 2 1/2" exhaust system.
In order to kill all the drone, I would have to have an exhaust system with so many resonator pipes that it looked like a porcupine on steroids....
Maybe I need to design a system that works like a slide trombone with an electric motor linked to the computer to lengthen or shorten the trombone slide...