Saturn S series Twin Cam cylinder head had now featured a new roller-rocker setup with hydraulic tappets and roller cams replacing the conventional bucket lifter setup of the previous engine in the S series. Also introduced for the 1999 model year S-series vehicles that were sold in California was a different type of an exhaust manifold that housed an upstream catalytic converter (this converter had heated up much faster than the conventional unit, and it had also decreased exhaust emissions faster as well), and it also had provisions for an air-injection reaction system (This had injected fresh air into the exhaust to reduce
Chem-E-Car one hour before the competition. The size of designed cars cannot exceed certain specifications and cars must operate using "green" methods, which do not release any pollution or waste in the form of a visible liquid or gas, such as exhaust. The dimensions of the car are to be within 20x30x40 cm. This competition is hosted in the United States by the AIChE (American Institute of Chemical Engineers), and winners of the competitions receive various awards, depending on how they placed. The competition has various rules: Each car is required to have a poster board explaining how the car runs