There are just a few months remaining until Ford’s iconic muscle car, the Mustang, lands down under in factory right-hand-drive configuration. Already a hot seller in the USA, the Mustang’s popularity is set to continue here with Ford Australia already taking over 2000 deposits from prospective buyers before it arrives at the end of the year. But like all other car manufacturers, Ford is already looking ahead at how they’re going to facelift the current model Mustang in 2018.
Reports circulating this weekend suggest the Mustang will receive a new front end design – though we can expect subtle changes to the lights or front bumper arrangement here, as the Mustang already wears Ford’s global face. But more interestingly, the 2018 Mustang will potentially have a 10-speed automatic transmission as part of its mid-cycle refresh. In a torque laden vehicle like the Mustang, is a 10-speed transmission really necessary?
The current model will be available here with either a 2.3L turbocharged 4-cylinder engine developing 233kW of power and 432Nm of torque, or a larger 5.0L naturally aspirated V8 producing 303kW and 525Nm. Both will be offered with either a 6-speed automatic or 6-speed manual transmission. With both engines offering up a broad spectrum of power and torque, surely 6 gears would be enough, right?
Just a few years ago, Ford Motor Company’s chief engineer of transmissions, Craig Renneker, said in an interview that more gears gives their power train engineers more gear spread to work with. This means first gear can be shorter for better off-the-line acceleration while the top gears can be taller for better fuel economy. “If you had asked me five years ago whether an eight-speed would give better efficiency, I would have said no. Because the additional sixth clutch required for an eight-speed would have created more internal drag than the added gear span could offer. We’ve recently discovered how to reduce the clutch drag losses so that eight gears are beneficial. Now it makes sense to jump from the five clutches required for a six-speed, and the overall package saves 2 to 6 percent in fuel economy.”
Beyond offering better fuel economy, smoother shifts and improved acceleration, a higher gear count also helps with the all important marketing spin employed by manufacturers, giving customers the impression that the car is packed with sophisticated technology – after all, 10 speeds must be better than 9. But there’s also the question about reliability and transmission longevity. More moving parts means more potential for something to go wrong, let alone the added production and maintenance costs involved.
There’s also the question of how many gears can be designed into an automatic transmission before looking at a continuously variable transmission (CVT) becomes more viable. A CVT can pick from a nearly limitless choice of ratios, theoretically making fixed-gear transmissions obsolete. But issues remain with their ability to handle the power produced by larger engines, like those in the Mustang. There’s also the CVT’s tendency to leave customers feeling odd about the driving experience, as the engine and transmission don’t behave the way most drivers are used to. They’re very efficient gearboxes though, and with time this might change.
When considering efficiency, we also can’t forget the humble manual transmission either. It remains the most simple, most energy-efficient type of gearbox available in any type of vehicle. But there’s obviously a limit to how many gears you can fit to a manual before things get ridiculous, and while there will always be a market for them, the number of vehicles sold with manual gearbox continues to plummet.
All these transmissions will have their place, Renneker says: “What’s interesting in the industry today is while dual-clutch transmissions were under development, the planetary units were not standing still. They were getting better and better. As a result, there’s no one clear transmission type emerging as ‘The Future.’ DCTs, planetary, and CVTs are all alive and being developed, and all have a niche. As fuel-economy regulations become tougher and tougher, there’s going to be more customization that defines the optimum transmission for each application.”