From belt drive to the Koenigsegg Engage Shift System.
If we break a car's transmission down to its simplest and most essential aspects, its job is to regulate the power supplied by the engine to the wheels. It does this by changing the gears in the unit to optimize the engine's output compared to the speed of the car and its load. An automatic transmission takes care of everything for the driver. However, there are still enough car enthusiasts who enjoy controlling that aspect of the car for the manually operated transmission to live on and for manufacturers to keep developing them. And that's despite automatic transmissions now being more efficient and faster than using a clutch pedal to disengage drive, moving a lever manually, and re-engaging the clutch.
The first cars mainly used a belt to transmit drive power to the drive axle, making it a single-speed transmission. History credits the French inventors Louis-Rene Panhard and Emile Levassor for inventing the manual transmission with a three-speed chain-driven design in 1894. Louis Renault, the founder of the French automaker Renault, substituted the chain for a driveshaft and added a differential axle to create the basic drivetrain layout still used today. That car was the Renault Voiturette and launched Renault as a company.
The clutch, used to disengage drive from the engine to the wheels, had already been invented by the English engineer Professor Henry Selby Hele-Shaw in 1905. However, the gears were still basic and had to change using careful timing and throttle input to synchronize the speed of the gears to mesh the teeth together. Getting it slightly wrong would result in grinding and crunching noises and a rough ride for anyone in the vehicle, hence they became known as crash boxes. What was needed was some way to synchronize the meshing of the gears. Anybody else detecting some foreshadowing here?
Until the invention of synchromesh by the American engineer Earl Avery Thompson in 1919 (Thompson also invented the Hydra-Matic transmission for General Motors), drivers had to match the revs of the engine to the speed of the selected gear. That's known as rev-matching, and there will be more on that later. Synchromesh automatically matches the speed of the engine's input shaft with the gear selected. Using synchronizer rings to connect two moving parts rotating at different speeds, the only way to grid gears was by not depressing the clutch pedal properly. There's no quick and easy way to explain how synchromesh works, so the best way to think of it is a small clutch that speeds up or slows the relative speed of the required gear for engagement.
The first cars to use synchromesh were from Cadillac and LaSalle in America in 1928. The first car to use a form of synchromesh in all forward gears was the 1952 Porsche 356. The 356 came with a four-speed manual transmission which was one speed more than most at the time.
Three- and four-speed units were normal until the late 1970s, although a few five-speeds appeared in high-end cars. These were also the decades of the gated shifter on higher-end cars, which is essentially a pathway for the shifter to move through the gear selection to ensure the driver kept the throws of the stick uniform. If you see a gated shifter on a modern car, it's just for looks and nostalgia, as current linkages are precise enough to make them redundant.
Regarding shifting patterns, the dog-leg take on the classic five-speed gate pattern wasn't uncommon for race and on-road performance cars from the 1950s to the 1990s. It puts first and reverse gear together in the shifting pattern rather than first and second. That makes shifting between second and third and between fourth and fifth simpler and quicker actions to perform. Notable cars that used a dog-leg pattern for shifting include the 1960s Ford GT40, early Porsche 911s and the 924/928 models, the European BMW E30-generation M3, most Ferrari models from the 1960s through to the mid-1990s, and many Lamborghinis of the same era.
Another relic from the past is overdrive, which became popular in the 1970s. An overdrive unit was an additional high gear for cruising. It could be factory installed or come from the aftermarket and was actuated separately, most commonly by a button, switch, or lifting the accelerator when above a certain speed. Its chief purpose was fuel economy.
It was the 1980s when synchromesh in all forward gears and four- and five-speed manuals became the standard, and overdrive became obsolete in new cars. Automotive lore suggests it was the Fox-body Mustang in 1983 that pushed the five-speed as a standard. Then, in the 1990s, six-speed manuals appeared regularly on high-performance cars. The 2012 Porsche 911 introduced a seven-speed manual, but that didn't stick (pun intended), and the majority of modern manuals are six-speed.
For performance driving, the art of rev-matching downshifts is essential, despite the advent of synchromesh. While synchromesh does its job of meshing the gears, a sudden downshift has the same effect as adding braking on the drive axle. Downshifting can affect stability under braking and cause all kinds of issues, but timing a blip of the throttle before lifting the clutch properly to match the speed of the lower gear smooths out the change. Technology loves to automate complicated or hard-to-time tasks, and braking while blipping the throttle at the right moment while changing gear with only two feet for the three pedals is just that. It's also laborious to do in traffic when you want to treat your clutch well.
Nissan first introduced SynchroRev Match, which blips the throttle on the down and upshift, to the 370Z in 2009. It was part of the Sport package on six-speed manual transmission models, although the 350Z had an earlier version of the same system. Since then, similar technology has appeared on cars like the BMW M2 CS, Honda Civic Type R, Chevrolet Camaro SS, and the recent Ford Mustang Mach 1.
No Lift Shift (NLS) is General Motors technology that allows the driver to keep the gas pedal to the floor while upshifting. You can do it without the technology, but we don't recommend it if you want the clutch to last. It uses the engine's ignition system to adjust fuel and spark to control torque when a shift is detected. It allows for smoother and, theoretically, faster upshifts while acting as a safety device for novice manual drivers. The No-Lift Shift tech also takes the load off of the mechanical parts of the drivetrain and should help them last longer. Our favorite use of the technology is on the CT5-V Blackwing.
Koenigsegg can't help itself when it comes to revolutionizing automotive technology that is already considered mature. The Koenigsegg Engage Shift System (ESS) is an automatic nine-speed automatic transmission and a gated six-speed manual that you can shift yourself using an engaging clutch pedal. How it works is insanely technical and complicated and involves seven wet, multi-plate clutches with pressure sensors and hydraulic actuators to open and close as required on each clutch. For appearance's sake, the shifter is gated in a straight six-speed pattern with reverse on the right side. However, opposite reverse gear is a slot for the stick to put the transmission in full-auto Drive mode. The manual system is clutch-by-wire, meaning there's no physical connection to the moving parts from the clutch pedal. Of course, people may complain about the feel, but they'll likely never drive a Koenigsegg CC850, and Koenigsegg says it will feel fantastic and will be the best shifting experience ever.
Anyone that drives a manual should, and experienced track drivers do, fear the money shift. Usually, it happens in cars being accelerated hard that a driver is new to, and comes about when shifting into the wrong gear, typically from third to second instead of from third to fourth. BMW's upcoming tech is sketched out to use a sensor that can detect what gear the transmission is in and what speed the crankshaft is moving at. It could also determine the viability of a downshift based on the car's speed and not allow it. Looking at the patent and the idea, it should be non-intrusive right up until it's needed. Ideally, it should never be needed, but M cars are not cheap, and if you track them, the chances of a money shift grow.
What's next? We don't know, but the manual will live on in Pagani hypercars, BMW M sports cars, and Honda hot hatches for years to come.