There are some things in the car world you just take for granted. Gearboxes are the perfect example. Every driver understands how to use them and most car enthusiasts understand what gear to be in for best performance in a given situation. But how many people can actually explain what a gearbox does? Not many, we bet. But that’s perfectly understandable, as not only is it quite a hard thing to understand. But on the face of it, understanding gearboxes doesn’t seem to be any big advantage to even the most ardent car tuning fan.
In reality though, the right choice of gearbox – and we don’t just mean automatic, manual, or the number of gears it has – can have a dramatic transformation on the way your car performs. Read on… Imagine you own a modified car pushing out 400lb/ft at 4,000rpm – and for the sake of this explanation, this is the revs per minute we will be looking at in each gear.
Starting at the top, 5th gear is an overdrive gear, meaning gearbox torque output is less than the engine torque output. This means while only 301lb/ft comes out the gearbox, the rpm is much higher than what the engine is doing – over 5,300rpm – allowing for the car to reach a decent top speed.
Fourth gear is a 1:1 gear, so the
