Manual vs. automatic transmission MPG showdown: Nissan Micra 1.6L
 

http://ecomodder.com/forum/attachmen...1&d=1411481277

These brand new Nissan Micras may look identical, and their official fuel economy ratings also say they're almost twins... but in the real world, they're definitely not!

The car on the left has a 4 speed conventional automatic transmission, and the one on the right has a 5-speed DIY gearbox.

Thanks to Cornwall Nissan, last week I got a chance to put the 2 cars through a head-to-head (simultaneous) MPG comparison on a 20 km (12.4 mi) round trip route.

The car's official 5-cycle EPA style ratings:

• Manual city/hwy/comb: 27.4/36/30.6 mpg US = 8.6/6.6/7.7 L/100 km
• Automatic: city/hwy/comb: 26.7/36/30.2 mpg US = 8.8/6.6/7.8 L/100 km

(For those of you south of the 49th who don't get the Micra, the car's drivetrain and platform is the same as the Versa sedan/Note.)

Route: This was a mostly city drive: a mix of urban (~40%, max. speed ~60 km/h = 36 mph) and ex-urban (~50%, max. speed ~80 km/h = 50 mph) roads, with one brief freeway sprint between interchanges (~10%, max. speed 110 km/h = ~68 mph).

Conditions: cool 10C / 50 F, but sunny & dry.

http://ecomodder.com/forum/attachmen...1&d=1411481929

Driving style: There was actually precious little eco-driving in this comparison, because my dad joined the fun and he led the parade in the automatic. Let's just say that he's a typical driver of the "binary pedal" school (either on the gas or on the brakes). Speeds were around 5 to 10 km/h (3-6 mph) over the posted limit.

To make it a valid comparison, I followed in the 5-speed car and made sure to accelerate as quickly as my dad did in the automatic, and brake as late as he did. There was no neutral coasting, no pulse & glide or anything like that. And I stayed back far enough so there was no unfair aero advantage (draft) for the 5-speed car.

The only significant eco-driving technique I used was upshifting to the tallest possible gear after accelerating. Often that meant 5th gear at as low as 50 km/h / 30 mph on a level road. If I needed more power, I downshifted.


Results:

Forget the official ratings! Once again we see how the EPA testing handicaps manual transmission cars due to dictated, non-eco shift points during dyno testing.


http://ecomodder.com/forum/attachmen...1&d=1411481277

Translation:

• 5.1 L/100 km - manual (46 mpg US / 55 mpg Imperial / 19.6 km/L) *
• 6.5 L/100 km - automatic (36 mpg US / 44 mpg Imperial / 15.4 km/L) *

* Note the Micra's onboard display is a bit optimistic. The display in the Micra SR automatic loaner I drove in July read 4.5% higher than actual fuel economy calculated at the pump.


Moral of the story: if you're comparing a manual vs. automatic vehicle based on the EPA ratings, beware of false automatic hope! Even when the numbers are close, a manual is typically capable of better real world economy, and not even using "hard core" techniques. Just upshift early and upshift often. (The extra techniques are gravy.)


A caveat about this test: the conventional torque converter style 4-speed in the Micra is going to fare worse in a comparison against a manual than a CVT or dual clutch auto/robotized manual would. Newer style automatics are definitely closing the gap. But I'd still get the manual, even if the automatic is rated a little higher. (Such as in the case of the Mitsubishi Mirage, where the CVT is rated quite a bit higher, but owners are getting better mileage with the manual in the real world.)


For full details of the Micra showdown: Head to head: 2015 Micra manual vs. automatic MPG/fuel economy comparison - Micra-Forum.com

Crawling on the Interstate coming west to my house, reminded me of why I don't mind the auto, not that I would not prefer the manual but this auto is decent with 4 gears and a lockup converter.

It needs their latest CVT, then it would cut the gap in half maybe more.

regards
mech

While most people insist that low-quality robotic butlers are more efficient than "DIY" (I am not sure everyone will understand that. You made the gearbox yourself?), one friend said they do that so people pay extra for the automatic, thinking that it would pay off at some point.

I hear you. The Micra's automatic is certainly pleasant enough to drive - essentially seamless shifts at low engine load. And it actually has fairly aggressive programming to get into lockup and hold higher gears.

Yep. Ironically, both of the Micra's closest competitors -- Chevy Spark and Mitsu Mirage -- use Nissan-sourced (JATCO) CVT's. And they have much better ratings than the Micra.

However one Micra owner pointed out to me that there's an argument to be made for the old-school 4-speed automatic in terms of total cost of ownership over the long haul: the manual will probably need a pricy clutch replacement in its lifetime, while the CVT needs expensive periodic fluid changes. The 4-speed auto needs neither. YMMV.

There's certainly a lot of profit in the automatics, especially this old-school 4-speed!

The wife's Rogue had a 10 year 120k warrantee on the CVT. The fluid is expensive but it does not hold that much. On my Insight it was around 2 quarts. Cost around $100 fror them to change it.

On Nissans, I think there is a fluid change warning system that tells you when to change it, but I think the 06 Murano went 95k without any indication of fluid degradation.

Depends on how you drive it and if you tow or not. The Murano was rated for 3500 pounds with the CVT. They have done something to increase the spread between lowest and highest gears. It used to be about 650%, now I think over 800% range between lowest and highest and they did mods to reduce losses. Think the newer ones have two ratios instead of one. The newest Rogue is rated at 32 or 33 highway while her 09 was 28 if memory serves me.

regards
mech

Next Generation XTRONIC CVT | Nissan Innovation Labs

They have the Altima running at 1500@60 MPH, with a 38 highway rating same as my old Fiesta, except the Fiesta was about 2200.

Correction, the ratio spread (lowest to highest) is 7.3 not 8 versus the older 6.

regards
mech

I had the chance to compare the new Mitsubishi Mirage's CVT against the manual transmission version over the same route (100% city driving). In that case, the CVT actually has better ratings than the manual for both city & highway.

As you might expect, the difference there was smaller than what we saw with the Nissans, to be sure: 42 mpg US (CVT) vs. 48 mpg (5-spd).

http://ecomodder.com/forum/showthrea...age-27384.html

A 14% improvement for the Mitsu 5-speed vs. 27% with the Nissan manual.

But it also wasn't as good a test: it was me driving the two Mitsus on successive laps, not head-to-head like we did with the Nissans under identical traffic and accel/cruise/decel conditions.

In my entire driving career (99% on manuals since 1973), I've never had to replace a worn out clutch. For me the gear teeth, bearings, or fork wear out well before the clutch lining is gone.

I'm in the same boat. I've only once had to replace a clutch, and it burned out because of a mechanical problem (rust on the clutch arm preventing it from fully engaging). Not because of the nut behind the wheel.

But I'm also going to say you're not probably representative of the average manual transmission driver. Just look at your car! :)

(By the way: I got your e-mail. Will get back to you.)