As the years go by, the dramatic change in vehicle design is as obvious as black and white. A slower, but just as obvious, change is in the functionality of the transmissions. Finally, here is an ultimate showdown between them. For the majority of drivers, automatic transmissions have become just a way of life, and with each passing year, the number of people who have the ability to operate the classic manual steadily decreases. Now with a newer hybrid of the two, stepping in with shifting speeds exceedingly faster than its predecessor, the question is now, which is superior. For the daily commuter and non-performance driver, automatics have supplied them with peace of mind and have removed the challenge of shifting by putting a computer in charge. As a result, the connection between a driver and his vehicle has gone along with that.
Although it may look pretty simple for the unaware user, traveling between point A and B in a vehicle requires a complex process, which includes, but not limits to fuel and air intake, ignition, and exhaust happening inside the engine. Also, the power from the engine is transmitted further to the wheels through a system of gears, known as a gearbox or transmission.
The main purpose of a gearbox is to create a spinning ratio between the engine revolutions and the wheels, developing enough torque to get the car moving from a complete stop or allow it to climb a steep hill, while providing enough horsepower when traveling at high speeds on the highway or the track. Right now, there are three main types of transmissions used worldwide:
There are several differences between the three, including their mechanics, and also in terms of efficiency, as one will be able to conclude from the following paragraphs of this article.
Manual gearboxes have been the most used type of transmission in the past 50 years, due to their relative mechanical simplicity. The main difference between a manual transmission unit and the other two types is represented by the manually engaged clutch, which connects or disconnects the engine from deliver power to the gearbox. Once the clutch is engaged, the engine transmits power to the transmission through a shaft. The power then gets further through a layshaft and a series of gears, then through the differential and the final drive shaft, which connects to the wheels of the vehicle.
Since you can switch between gears at your own liking, using the gearstick inside the vehicle, a manual gearbox allows better control of the RPM range and implicitly the torque and horsepower being delivered to the wheels of the vehicle. In the past, manual transmissions were known to almost always deliver better fuel economy than their automatic counterparts. In recent decades, this has slowly began to change, as automatics are using more and more ratios that outnumber and outperform the efficiency of the manual version. The fuel economy of a manual may still outperform that of its auto counterpart in some cases, although it really just comes down to the driver.
While enthusiasts are all about operating the clutch and executing fine heel to toe maneuvers, many find the idea of the third pedal an unnecessary evil. Thus, a considerable extent of car buyers orient themselves towards vehicles using semi-automatic gearboxes. Instead of a gearstick travelling in an H pattern, semi-automatic gearboxes make use of a +/- lever in case of sequential systems or two paddle shifters placed behind the steering wheel.
Although the concept features an incredible simplicity, there hasn’t been a perfectly executed implementation yet at the lower end of the market. High end vehicles using dual-clutch semi-automatics have proven time and time again to be the quickest and smoothest shifting vehicles on the market today, pushing the boundaries of what was thought to be possible. Delayed and unpleasant gear changes are the main issue with this type of gearbox, when not using a dual-clutch system.
While some find clutch pedals unpleasant, there are some who go even further in terms of gear changing simplicity, resulting in the choice of an automatic gearbox. Unlike clutch-operated transmission units, such as the manual or semi-automatic gearboxes, an automatic gearbox uses a torque converter. This removes the need to constantly disengage and then reengage the clutch whenever changing gears or halting the vehicle to a complete stop.
Torque converters connect the engine directly to the drive shaft through a bath of transmission fluid. Since an indirect connection is established this way, around 10% or less of the engine power is lost in the process. To counter this loss, some automated gearboxes engage a lock-up clutch at cruising speed in order to fully deliver engine power to the wheels.
Each planetary gearset is operated through a set of hydraulics and small clutches, working in an entirely different way than a manual transmission gear. Automatic gearboxes are the least used option at the moment, since they are heavier and require increased repair costs. However, automatics are recovering ground fast, as they are more reliable and provide a way better fuel economy than both manual and semi-automatic units.
Some drivers are biased towards certain transmissions and this has led to an intense debate online amongst the driving community on which is best. The truth is, every transmission configuration has its place in the market and may be better suited for certain situations than others, regardless of the perception of the public. That being said, not everyone cares that a computer may shift faster than their muscles allow them to, and for the most hardcore of driving enthusiasts, having a clutch pedal is the only option.
Written By: Roads Untraveled