7 aeromods + tire pressure = 11.6% gain at 90 kph (56 mph): 2015 Nissan Micra 5-spd

[MetroMPG]

Nissan sells the Micra in about 160 countries, and Canada joined the list for 2015. The US doesn't have it, but the Canadian version shares the same drivetrain & platform as the Versa Note & sedan (perennial best-selling subcompact in the States), so you've "seen" plenty of Micras whether you realize it or not.

One Micra owner said: "I tell people it's a Versa Note with a funky/retro body kit."

Basic stats (5-speed manual transmission):

• City: 8.6 L/100 km city / 27.4 MPG (US)
• Highway: 6.6 / 36
• Combined: 7.8 / 30.6

Drag coefficient: 0.315

Nissan loaned me one recently, possibly not expecting that I would duct tape coroplast and cardboard all over it for fun & edutainment.

Here it is stock:



The mods...

1. Tire pressure

Placard pressures are 33 front & rear. Super squishy comfy! I went to sidewall max (44) +1. And I prefer the overall feel at that level, personally.


2. Partial grille block

The Micra has a huge amount of open grille area for a little 109 hp car:



The diagonal lines show where the radiator is. Everywhere orange is wide open.

Considering this is the base Micra with manual trans and no A/C, its cooling requirements are bottom of the scale. There's absolutely no need for this much flow-through in normal conditions.

Solution: cut-out coroplast shapes, wire ties...



In this configuration, the cooling fan didn't come on once during a 440 km / 275 mile highway round trip (cruising between 80 kph / 50 mph to 105 kph / 65 mph, including city traffic with some slow & crawl and many stop lights. The max coolant temp was 197 F; the cooling fan turns on at 207 F; ambient temp was around 75-80 F.

Interestingly, the Versa Note, which has the exact same 109 hp engine/trans (manual, but not the automatic) has blocked off "faux grille" sections, plus it uses active shutters in the lower portion in the CVT version.

Another thing the Versa Note gets that the Micra doesn't is a stock air dam, so...

3. Air dam



It's lawn edging. Clearance is about 10 cm / 4 inches. It scraped occasionally, but only on very steep transitions.'

It was fun coming up with a rigid attachment without drilling anything! I re-purposed a bunch of existing holes underneath, plus liberal amounts of Gorilla tape.

Here's the Versa Note's front end for comparison. Also notice the blocked "faux grille" sections that the Micra didn't get?



4. Kammback

The base Micra doesn't get any treatment on the hatchback, though the top trim "sport" Micra SR gets what the company calls a spoiler, which looks to me like a (small) drag-reducing roof extension:



But bigger is better in the Kammback department:



5. Smooth wheel covers



I reused the discs I had made & tested on the '07 Honda Civic winter beater. Except these were just duct taped on the OEM wheelcovers.

They don't necessarily have to be ugly -- I shopped spun discs onto one owner's lowered Micra and think it looks great:




6. Rear fender skirts



They're just cardboard with plastic over top. It's a simple flat piece -- the size & shape was dictated by tire protrusion from the wheel arch.


7. Rear tire spats/deflectors



I'll admit size & placement was a bit of a guess. Both the Versa sedan (pictured, right) and Versa Note have 'em.


8. Passenger mirror delete



(Replacement interior convex mirror pic borrowed from another EM thread.)

A-B testing & results -- next post.

[MetroMPG]

A-B testing and results...




Conditions:

Temp 16 C / 61 F
Wind NE 13 km/h / 8 mph
Pressure 102.4 kPa
Humidity 42%

Test route:

Flat 2-lane highway; no traffic in my lane; occasional oncoming traffic; ~80% of the distance in a forested area (sheltered from NE breeze).



Results:

52.5 mpg (US) = 4.5 L/100 km = average, all A runs

47.0 mpg = 5.0 L/100 km = average, all B runs

11.6% / 5.5 mpg US improvement, A over B

------

I'd call that a healthy success. Some of these mods could be re-done and made to look OEM, too.

------

Raw numbers:

A (mods in place)

North ... South ... Average (MPG U.S.)
53.2 ... 52.3 ... 52.8
53.1 ... 51.6 ... 52.4
52.6 ... 52.4 ... 52.5
53.5 ... 51.2 ... 52.4

B (all mods removed/reversed)

North ... South ... Average (MPG U.S.)
46.4 ... 46.9 ... 46.7
47.3 ... 47.0 ... 47.2
48.2 ... 46.0 ... 47.1
48.1 ... 46.4 ... 47.3

STDEV all A runs: 0.5
STDEV all B runs: 0.7

[gone-ot]

MetroMPG, you sending NISSAN an e-mail with a link back to this posting?

[MetroMPG]

If I did, I have a feeling this would be the last loaner I'd get from them!

[Daox]

I'd say thats a great success.

[Fat Charlie]

... Or your next loaner could come with a check for the consultation. Either way, we'd all learn something about Nissan!

[redneck]

.

Awesome...

Nearly 12%...


I say show it to Nissan.




>

[Baltothewolf]

Yea I would show them the Kam-back, grill block and rear tire deflectors. The skirts wouldn't stick, as companies don't want to lose sales because of looks, but even without the skirts/wheel covers it's probably still a 7-9% increase.

[AbramWagner]

Very cool

[aerohead]

If you're going to persist in this type of behavior young man,we're going to insist that when in public,that you maintain the proper attire: Einstein hair wig,white lab coat,pocket protector with slide rule,and 1-inch thick horned-rim glasses!
Nice going.You just saved Nissan's R&D Dept. a couple million $$$$$$$$$$$$$$$
We'll look forward to these 'OEM' items in 2025.