Myth-Busting: Manual transmissions are more fuel efficient
This one relates to fuel economy with many holding to the belief that a manual is more fuel efficient than the same car with an automatic. So, are manual transmissions more fuel efficient?
UNFORTUNATELY, the manual transmission itself will soon become a myth. See, more on and more young drivers are opting for an automatic rather than shift gears for themselves. And, so car makers are responding. Indeed, you can almost count on two hands the amount of manual cars you can buy aimed at younger drivers. Sure, some makers still include them in the line-up to chase that ‘price tag’ that gets used on billboards and TV ads, but very few people are actually buying an entry level car with a manual. But I digress.
Onto today’s myth…and that is, that a manual transmission is more fuel efficient than an automatic transmission. But, unlike some myths, this one isn’t as easy to bust as you might think.
See, back in the old days it was a given that a manual transmission was more fuel efficient than an automatic transmission. And that’s because the automatic generally had less gears (there’s more to it than that, like the torque convertor, but gearing is one of the key reasons). This meant, a three- or four-speed automatic was generally revving higher at any given speed than, say, a five- or six-speed manual.
But those days are gone. Automatic transmissions often now run more gears than their manual equivalent (up to nine vs six-speeds) and they’ve spawned new classes of much more efficient automatic transmission, like CVTs and dual-clutch transmissions (which generally offer more gears than their manual equivalent). And it’s this and other features like locked torque convertors (that no longer slip) and just generally more advanced mechatronics that have made the gap between the two transmission types much smaller.
For instance, if we look at the Hyundai i30 with 2.0-litre four-cylinder petrol engine the difference, on the combined cycle, is 7.3L/100km Vs 7.4L/100km, manual vs automatic – both are six-speed units. If you consider the i30 diesel the gap (manual vs automatic) is a little wider at 4.5L/100km Vs 4.7L/100km. Then, the i30 with a turbocharged 1.6-litre four-cylinder petrol and it’s a dead-heat between the six-speed manual and the seven-speed DCT. Move away from a small car to a 4×4 dual-cab Ranger PXII and the 2.2-litre four-cylinder turbo-diesel mated to a six-speed manual drinks 6.8L/100km (claimed combined) while the automatic drinks one-litre more at 7.8L/100km.
In these cases, the major difference in fuel consumption is when you compare a manual transmission with a traditional torque convertor automatic… change up the automatic transmission type, like the dual-clutch transmission in the i30SR and there’s no difference in the fuel consumption (claimed).
And then there are those automatic transmission types that are radically more fuel efficient than their manual equivalent. Like the CVT. Take the Subaru WRX, for example, it offers both a six-speed manual and CVT option…the manual (combined claimed) drinks 9.2L/100km while the CVT drinks 8.6L/100km. And it’s the same story for the Toyota 86 which, in manual form drinks 8.4L/100km and in automatic drinks 7.1L/100km (claimed combined).
So, while I’ve only grabbed a small sample size and while, on paper, manual transmissions are generally more fuel efficient than the automatic equivalent (although not in all, like the Toyota 86), the gap between the two transmission types is so small that I’d suggest it really is a myth that manual transmissions are more fuel efficient. Especially when you through CVTs and DSG (DCT) transmissions into the mix, which are either as efficient or more efficient than a manual transmission.
What you can more easily argue is that a manual transmission vehicle is cheaper than an automatic, in some cases the difference can be up to $2000; and that’s a lot of extra money to spend on fuel in the manual.