Dirt Logic 4.0 Resi Coilover. The Dirt Logic 4.0 provides the ultimate in hardcore offroad dampening capacity with superior highway comfort in a big package. This massive high end shock is designed for full size vehicles that required the biggest and best Coilover shock in a bolt on configuration. Nothing else comes close. Features 4.0in OD Stainless Steel Body. 3 58in OD Billet Aluminum Piston. 1 14in NitroSteel Black Piston Rod. Cold Wound Coil Springs. Adjustable Coilover Construction. 34in Spherical Ball Mounting Ends. 4.0in OD Aluminum Remote Resi. Extended Length - E26.64. Collasped Length - C17.51. Stroke Length - S9.130. Top Mount - B2 . Bottom Mount - B1.