A programmed heat-activated foam technology has recently been introduced for making baffles to seal hollow car body channels[1,2]. First, we summarize the key characteristics of the programmed foams. Some unique design features such as maximum gap to allow easy E-coat drainage, multiple section design for complex channels, allowance for passage of drainage hose and double-layered baffle are presented.Then, we examine the important design parameters affecting the acoustic performance of baffles based on the programmed foams. The insertion loss(IL) was measured for various baffles expanded in a test channel. The effects of foam expansion ratio, surface density, etc., on the acoustic performance of various single-layered and double-layered baffles are reported.