VTEC just kicked in, yo! is a catchphrase often used on 4chan (namely, /b/ and /p/) referring to sudden velocity experienced by a car with a VTEC motor. Since the situation is similar to entering warpspeed in Star Wars, jumping to Slipspace in Halo, or other sudden-velocity changing scenarios, this became a popular image macro representing speed in 2005.

From lurkmore.com/wiki:

First started on /p/ (photo board) in response to a picture of a Honda, VTEC refers to Honda's variable valve timing system, which is used to increase horsepower at higher RPMs. Since many /p/ regulars didn't think highly of VTEC, this expression was used to negatively describe any souped up Asian car (Ricer). Was a huge meme back in the day. Recently given new life thanks to the unfortunately named VTech Massacre which occurred on April 16, 2007.

In 2007, "VTECH just kicked in, yo!" was created, due to response to the April 16 shootings at Virginia Polytechnical Institute and State University.

See the Google Insights For Search analysis to see how VTECH influenced VTEC.