SHELBY GT 350 Member
Joined: Jan 2011
Location: Central Massachusetts
I think the "active valve" mufflers work with the control system in the car to "open up" the flow through both sides to make it louder, or close one side down to make it quiet . . . so if you want it to be loud all the time, you could hard-wire it open; but you won't be able to make it quiet unless you have the control system in the car, which you don't.
I am not sure if the GT mufflers are compatible with the ecoboost piping and hangers, but suspect they probably are. So if you can get the muffler super cheap, it might be worth a try.
But yeah, more likely more trouble than it is worth; simple solution is to buy a louder "axle back" aka "muffler" that is made for your car.
| 2010 GT coupe | Daily Driver with some Steeda and GT500 take-off stuff for the occasional track day