When the Micra was launched back in May, I had the chance to drive both the manual & automatic transmission models on the exact same city/highway route in & around Montreal. Of course, I made a point of noting the fuel economy from the onboard computer in each car.
The manual reported 5.1 L/100 km (55 mpg Imperial / 46 mpg US), while the automatic said 5.6 (50 mpg Imperial / 42 mpg US). I used basic eco-driving techniques.
The downside to that comparison was that it wasn't a true head-to-head match. Yes, the route was identical. But the laps were run consecutively, not at the same time. So the problem was that even though I consciously *tried* to drive the cars similarly (eg. same rates of speed, acceleration & deceleration), I couldn't be certain that I did. Also, traffic patterns were probably different between runs, so I couldn't be sure I'd hit all the same slowdowns, not to mention traffic lights. See all those grains of salt? Take one!
What I really wanted was a head to head comparison: the exact same traffic conditions; same stop lights; identical weather/road conditions; same rates of acceleration, cruising & deceleration.
Guess what? Last week, I got the chance to do just that.
Thanks to Cornwall Nissan...
The extremely helpful folks at Cornwall Nissan made it happen. (If this sounds like a plug, that's because it is and they earned it: if you're in the market, drop by their dealership and talk to the friendly staff who went above and beyond the call of duty to help me out!)
Micra SV automatic (left) and Micra S 5-speed manual at Cornwall Nissan
I had originally hoped to do this comparison back in July, while I had the automatic SR on loan from Nissan Canada. At that time, I called around to my area dealers to see if anyone had a manual Micra I could borrow for half an hour. Shockingly, there wasn't a single manual Micra at any of the 4 closest dealerships. Lots of automatics, just no 5-speeds.
However the folks at Cornwall Nissan quickly offered to let me know as soon as one came in, and sure enough I got a call from them last week. "Come on down!"
Let's cut to the chase. After 20 km (12 miles.) of city & ex-urban driving, with a ~2 km freeway dash thrown in for good measure, here's what the fuel economy computers said:
- 5.1 L/100 km - Micra S manual transmission (55 mpg Imperial / 46 mpg US / 19.6 km/L) *
- 6.5 L/100 km - Micra SV automatic transmission (44 mpg Imperial / 36 mpg US / 15.4 km/L) *
Both Micras were brand spanking new (<100 km). The manual was a base S and the automatic was an SV. Both had full tanks of gas (7/8 in the SV). Both cars began from a cold start.
* Note the Micra's onboard display is a bit optimistic. Displayed fuel economy in my Micra SR loaner indicated 4.5% better than the actual fuel economy calculated at the pump.
Unlike Montreal, there was little eco-driving this time around. I drove the manual car, following my dad who joined the fun and led the parade in the automatic.
Let's just say that my dad's not much for reading traffic and playing the momentum game; I'd call him more of a "binary pedal" driver (either on the gas or brake). So the rates of acceleration and braking were what most drivers would probably call "normal", as were speeds: around 5 to 10 km/h (3-6 mph) over the posted limit.
I made sure to accelerate the manual car as quickly as my dad did in the automatic, and brake as late as he did. There was no neutral coasting or anything like that. And there was no "drafting effect" -- I stayed back far enough so there was no unfair advantage to the 5-speed car. No Micra NASCAR shenanigans here.
Fortunately, we lucked out at traffic lights as well: all the red lights caught both cars (instead of catching just me in the following car).
I used only one eco-driving technique in my manual driving style: I upshifted to the tallest possible gear after accelerating. In other words, I went to the highest gear that wouldn't lug the engine: sometimes that meant 5th gear at as low as 50 km/h on a level road. If I needed extra power to accelerate or climb, I downshifted.
Conditions & route ...
The weather was brisk, but otherwise sunny & dry:
- Thurs, Sept 18, 2014, 10:30 - 11:00 AM
- temp: 10 C / 50 F
- wind: N 9 km / 5.6 mph
- 66% humidity, 101.93 kpa pressure
Click image to zoom in on route. Or see Google Maps, Cornwall Ontario - https://goo.gl/maps/qhebw
The round trip route covered 20 km (12.4 miles) and included a mix of urban (~40%) and ex-urban (~50%) roads, with one brief freeway run between interchanges (~10%).
- Start: Cornwall Nissan
- north on Brookdale Ave
- east on Cornwall Centre Rd
- south on McConnell Ave
- west on highway 401 / McDonald Cartier Freeway, exit at Brookdale Ave
- south on Brookdale Ave
- east on Ninth St
- south on Pitt St
- west on Second St
- north on Brookdale Ave
- Finish: Cornwall Nissan
Why does the manual do so much better than the automatic when their ratings are nearly identical?
The combined fuel economy rating of the manual Micra is just 0.1 L/100 km (~1 mpg) different than the automatic. So why does the manual seem to do so much better in the real world?
The government test handicaps manual transmissions
Government fuel economy ratings for manual transmission cars are handicapped by the testing method. They seriously underestimate the car's MPG potential in the real world in the hands of a driver willing to do one simple thing: upshift, upshift, upshift.
Official fuel economy tests dictate the specific speeds when the manual transmission test driver must upshift or downshift during the procedure. Why? For repeatability the same car must always return the same result on the dynamometer, so the test drivers can't choose their own shift points. They have to follow designated shift points that are decidedly not fuel economy-friendly.
Manufacturers know this, which is why manual cars fitted with shift indicators or "eco" lights constantly encourage the driver to do one thing under light engine loads: upshift, upshift, upshift! They know that the lower the engine RPM for a given road speed, the better the owner's real world fuel economy.
If you don't make a similar habit of upshifting for economy & downshifting for power, your fuel economy will be closer to that of the automatic.
The automatic warm-up hit
"Warm-up mode" is another small reason why automatics are less efficient. After a cold start, the car follows programming that causes the transmission to hold on to lower gears longer (for higher engine RPM) to speed up engine & transmission warm-up for reasons of emissions, driveability & durability.
Since both Micras were started from cold for this comparison, the automatic car experienced the warm-up hit.
Conclusions & observations
First: the good news is it's obviously much easier to achieve/beat the Micra's official combined fuel consumption ratings regardless of which transmission you have. (Provided you drive reasonably, of course.) The new 5-cycle fuel economy ratings that apply to 2015 and newer vehicles in Canada are very different from the old 2-cycle ratings, which most drivers found difficult or impossible to get.
Second: Kudos to Nissan for for including a factory fuel economy display in all trim levels of the Micra. Feedback is critical for drivers interested in getting good fuel economy.
Third: if you're interested in fuel economy and willing to shift your own gears, remember the manual's ratings don't tell the whole story. Upshift early and often, and reap the rewards.