Dual Mode Mufflers

[MandarinaRacing]

I'm sure therre's some of you that's heard of this before. They were used on the Mustang FR-500. Basically what they do is that under normal idling and low speed, the mufflers work just like a regular muffler, under high loads a traps door open and they become a stright through design.....ultimate sleeper material
Too bad FRPP only sells the whole kit
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http://www.musclemustangfastfords.com/tech/0201mmff_500exhaust/[/url

 

[Anonymous]

a few companys sell cutouts that fit on the end of your headers, flip a switch and yer running exhaust outta yer headers and nothing else. flip the switch back and your running it through your full exhaust.