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
Aftermarket exhaust parts pipe or the pipes temporarily merge. This is to equalize the pressure in both exhaust pipes. Exhausts emit a large amount of heat into the engine bay, which can have a negative effect on engine performance by raising the underhood temperatures. As a result, high temperature insulation is used, more commonly known as heat barriers, for exhaust heat management. Thermal barrier ceramic-coatings are specifically designed to reduce heat loss from engine exhaust system components including exhaust manifolds, turbocharger casings, exhaust headers, downpipes and tailpipes. When used under-bonnet, these have the positive effect of reducing engine bay temperatures, therefore lessening the