Called direct the exhaust gas (also known as a linear array of vent, through the exhaust gas), i.e. out from the exhaust manifold, segment remove the catalyst (the catalyst is a green material) and the last row, directly to the exhaust gas into the air, so emissions effect, more suitable for long runs and high-speed race track, the sound is generally more than 100 decibels, a sense of shock when dealers are more obvious, and there is no exhaust gas after treatment can cause serious pollution, enhance high speed horsepower. Unsatisfactory low speed torque, will lose a certain torque. Straight row remodeled general exhaust noise increases, excessive exhaust emissions.
Advantages: exhaust smooth, strong torque high speed; disadvantages: low speed soft power, noise.