Sequential and dual-clutch gearboxes each will let you manually choose gears and not using a clutch pedal, however that does not imply they’re the identical. This video from elements provider FCP Euro explains the variations between these two varieties of transmission.
In addition to promoting elements, FCP Euro has a race group that ran the Volkswagen GTI TCR for 2 seasons. That supplied a very good alternative for a gearbox comparability, as the TCR race vehicles began out with a modified model of VW’s Direct Shift Gearbox (DSG) dual-clutch transmission utilized in the GTI highway automotive, however have been later upgraded with Sadev sequential transmissions.
The inside layouts of the two transmissions are very completely different. The TCR-spec DSG has two enter shafts, every with three gears. They’re positioned on both facet of an output shaft, which sends energy to the axles (one in every of which is shorter than the different), and interact the shaft utilizing synchronizers, identical to different trendy road-car transmissions.
2018 Volkswagen Golf GTI TCR (Photo by FCP Euro)
The sequential gearbox has all of its gears lined up on one enter shaft, and they interact the output shaft utilizing canines. That permits for no-lift shifts, but additionally requires the use of a rotating barrel as a substitute of shift gates. This transmission additionally permits for equal-length axles, serving to to regulate torque steer in the front-wheel drive GTI TCR race automotive. FCP Euro reckons it is about 100 kilos lighter than the DSG, too.
The gears themselves are additionally completely different. the DSG transmission (and all transmissions designed for highway vehicles) makes use of helical-cut gears, whereas the sequential ‘field makes use of straight-cut gears. Helical-cut gears have angled tooth, permitting them to mesh extra easily. Straight-cut gears make a high-pitched whine, however in addition they switch energy from the engine to the wheels extra effectively.
Overall, the major difference between a sequential and dual-clutch transmission is that one is designed for racing, and one is not. VW’s DSG transmission shifts rapidly, but it surely’s additionally designed to be easy and quiet. Sequential gearboxes are loud, and require important pressure to have interaction gears. The Sadev gearbox’s light-weight flywheel and tiny clutch additionally make it just about ineffective for low-speed driving. But none of that issues in a race automotive, the place it is all about getting the energy to the floor as rapidly and effectively as potential. For that job, a sequential gearbox is the better option.