i have a turbo 5.0. the motor itself it stock, only upgrade is an explorer upper and lower intake manifold. stock cam, piston, and all. car makes 307whp, and 423rwt @10.5 psi. my question is would it help me even just a little bit if i ran open down pipe or would it hurt me at all? i know it will sound like crap. just want to do it for the track. the down pipe opens about mid drive shaft area roughly so about a foot and a half before the mufflers. thanks guys.

 

Reducing backpressure on any forced induction engine is a good thing. You'll probably pick up some power. Might change the power curve slightly also.

 

as long as your running a straight through muffler you will gain nothing or close to it because you should have no back pressure already