Tesla Model S, Chevy Volt, Nissan LEAF, Prius Compete In Car & Driver Wind Tunnel – Video

JUN 11 2014 BY JAY COLE 30

Tesla Model S - Surprisingly Super Slippery

Tesla Model S – Surprisingly Super Slippery

When you are looking to maximizing the range and efficiency of a plug-in car,  aerodynamics always play a big part.

Last week Car & Driver set out to find out just who and what cars did it the best.  Included in the test was 2 fully electric cars, 1 PHEV…and of course the leader of all things ‘hybrid’.

  • Chevrolet Volt
  • Mercedes-Benz CLA 250
  • Nissan Leaf
  • Tesla Model S P85
  • Toyota Prius

The above video walks us through the process of quantifying the coefficient of drag area of all the contenders; and of course the results.

First place for Cd (drag coefficient) went to the Tesla Model S at an extremely low .24,  which help the EV tie with the Toyota Prius for the overall CdA (Cd x frontal area) rating of 6.2 feet – despite having the most frontal area overall.

The Tesla Model S, Despite Its Largest Footprint Still Ties For #1 Spot

The Tesla Model S, Despite Its Largest Footprint Still Ties For #1 Spot For Drag Area

  • Toyota Prius  – .26 Cd, 6.2 feet CdA
  • Tesla Model S  – .24 Cd, 6.2 feet CdA
  • Chevrolet Volt  – .28 Cd, 6.7 feet CdA
  • Mercedes Benz CLA 250 – .30 Cd,  7.0 feet CdA
  • Nissan LEAF – .32 Cd, 7.8 feet CdA

Besides watching the video, check out Car & Driver’s feature story on the testing here.

Categories: Chevrolet, Nissan, Tesla, Videos

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30 Comments on "Tesla Model S, Chevy Volt, Nissan LEAF, Prius Compete In Car & Driver Wind Tunnel – Video"

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What? No i-MiEV? Oh yeah, it has the aerodynamics of a brick. Carry on. 😉

Random note to add to this:

US spec i-MiEV: .35 Cd
“Old School” (Japan/Euro) i-MiEV: .33 Cd

Leafs aren’t aerodynamic? Feehhhhh….

I though the ugliness of the Leaf design was all in name of better aerodynamics. Prius surprise me, who wouldn’t think that the appliance style has 0.26

Part of the aerodynamics of the LEAF is for wind noise reduction.

The Bulging headlights are supposed to help with the side view mirrors. But the basic shape isn’t all that great . . . especially that back end.

Another thing with EVs . . . make nice smooth bottom! Take advantage of the fact that you don’t have to have a big hot engine that drips oil and a hot exhaust system. Just put a plastic sheet on the bottom at least.

Tesla seems like the only ones that paid attention to a really good aerodynamic design. This really is a CRITICAL factor for EVs since batteries are heavy/expensive and drag reduces range.

Compared to the typical car it is still pretty aerodynamic.

I remember some Nissan Reps saying that for next gen they won’t go out of their way to make it look unique.

Hopefully that will fix both the ugliness and aerodynamics problems.

one thing about the leaf design is that it has a higher roof and better visibility. of the cars listed above, i think that the Volt is the best designed, but one drawback to the Volt is that the sight lines are not so great.

Although the A pillars in the LEAF are *terrible* for visibility. It is easy to miss a pedestrian waiting to cross a street. “A” pillar is too far forward.

That is only true for the frontal visibility with the exception of the A pillars as Steve mentioned. I’ve found that rear visibility in my 2011 Leaf is atrocious. Between the headrests and the large rear pillars, I have extremely limited rearward visibility that can block a Suburban from view! I recently sat in a 2013 Leaf and from what I can tell, they made some marginal improvements, particularly to the rear headrests, but I think it’s still pretty bad. Hopefully this will be fixed in the 2nd Gen Leaf.

I wonder if the Volt is still 3rd with the mirror buffering upgrade.

I’m confused. You say in that picture caption that it ties for 1st but the picture itself and indeed the data says the Tesla is #1 albeit by a narrow margin.

Damnit Nissan. It’s ugly AND a total aero loser? Can you at least approach Prius drag levels for the next generation, PLEASE? Everytime I go on the highway I’m going to be crying about wasted kwh.

…crying about wasted kwh, but still laughing all the way to the bank about gas savings. That’s got to be interesting for folks in other lanes to watch.


Government regulations still require a physical rear view mirror on both side of the car. Tesla tried to get exceptions so they could remove theirs, but it just hasn’t happened yet, but I imagine it will within a couple years. No longer is just Tesla asking for cameras to replace mirrors, many manufacturers want to get rid of the drag they cause.

Nisan claims .29 CD for the Leaf…?

Do us a favor on the next one. Replace the side mirrors with side and rear view cameras; and, loose the barndoor headlights. On a car that needs all the help it can get on range, fancy frog eye lights are a waste.

More effective than removing mirrors would be some attention on reducing the size of the “hole” the car leaves at the rear – you know, like what the Prius, Tesla and Volt do.

The roof-line is simply too high and the awkward rear haunches also screw up airflow around the back.

It also seems that Nissan paid next to no attention to the drag around the wheels. The stock 16″ wheels are nowhere close to aerodynamic and the wheel arch openings are far larger than they need to be.

About the only thing Nissan got right was the underbody, but even there is room for improvement – compare it to the Tesla Model S.

At 65 mph about half the drag on a car is aerodynamic drag. So simply dropping the LEAF drivetrain into a Prius or Model S body would improve efficiency at 65 mph by 10%. All of a sudden, the 84 mile LEAF turns into 92 mile LEAF and is less than 10% away from the magical 100 mile range EV. Nissan could add 5 additional battery modules to the car and get to 100 miles.

0.29 might be the 2013 Leaf? The comparison here used a 2012 model, and I understood there to be some (minor) aero improvements for the 2013 model.

Regardless, I’m not crying about my Leaf: I bought it for surface street commuting where aero matters little, and the ease of getting my baby in and out of the back doors matters more. I got a good laugh when my pediatrician’s young daughter told me her parents frequently bumped their head getting their infant in and out of their Model S’s back doors.

i do look forward to getting an inexpensive and efficient highway cruising EV someday, but neither the Leaf nor Model S fit the bill just yet.

I agree with those silly Bludging headlights what silly French design school forced that rubbish on the Japanese designers.
It’s not just on the Ev’s it’s on general cars and looks like the designer was on drugs having a bad day. Children have more sense of aesthetics

For the Leaf.
While your at it, just plug all the cut and hole for ventilating something that need so little of it.
Just use the wheel well for air intake if you need somme, sine the opening are already there.
The antenna could be just straight out rear on a horizontal plane and it would’t impair signal transmission.
How about the opening for the wiper blade.
Those comment are free, so use it!

I think i3 would not be good in this test…

I know all you cars-as-fashion-statement types won’t care, but I thought this would be interesting to consider.

The 1990s Honda Insight was 5.1 sq ft CdA, and the VW XL1 is 3.0 sq ft CdA.

The BMW i3 EV is 7.4 sq ft CdA, and the Rex version is draggier at 7.6 sq ft, but they still have lower Wh/mile EPA average than any other electric cars, because of the light weight, and low rolling resistance.

Imagine if BMW offered the i3 chassis with a body like the VW XL1 at less than half the drag. You wouldn’t need a range extender!

First off, why the “surprisingly slippery” comment?? From day one, Tesla has been very vocal about the MS’s super low CdA. You would have to have been asleep to miss it.

But, more importantly, what does one unit of CdA mean in terms of efficiency? I know it’s a complex formula based on speed, temperature and other environmental factors. How much of a difference does, say, 1 additional sq ft of CdA make in terms of wh/mi? 1%, 10%, 50%??? For city traffic where the average speed is probably 30 mph, I don’t see CdA as a very big factor. Sure, for driving 70 mph it comes into play but, again, it would be nice to know how significant. I heard a lot “wow, that’s a draggy dog” comments about the LEAF but what does it really mean? 280 wh/mi vs 300?

I suspect the answer is not nearly as significant as many posters here think.

On the last page of the test, they give how much horsepower it takes to defeat the aero drag at both 70 mph and 100 mph. I would expect that the percent difference between wh/mi would roughly match the percent difference between the hp requirements at each speed:

Aero Power@ 70 mph:
16 hp 16 hp 18 hp 14 hp 14 hp

Aero Power@ 100 mph:
45 hp 48 hp 53 hp 42 hp 42 hp

The Law of Conservation of Energy pretty much ensures that it will take proportionally more electricity to generate proportionally more horse power.

Although with that said, other factors like tire drag, vehicle weight, and drive-train efficiency will also come into play, and will influence the numbers enough to keep it from being a straight line calculation.

Breaking the tie by giving the bigger car special credit, was interesting. It is sort of like giving the gold medal in the 100-yard dash to the chubby runner, because he had to make up for being chubby. Another way to break the tie would be to compare the down-force data. Car designers are always caught between choosing more down-force, or choosing less wind resistance. They both have the same rear axle lift (axle lift is negative down-force — you want down-force, not lift). But the Prius has 27 lbs more down-force on the front drive tires. The Tesla has 23 lbs of axle lift, while the Prius has 4 lbs of down-force pushing the drive tires onto the pavement for better grip. A valid argument could be made that the tie-breaker should go to the Prius, since it is generating more down-force for the same amount of air resistance measured. This would be a valid argument, because anybody can make a vehicle that has very little wind resistance, if they are willing to sacrifice down-force. The result would be the car becoming less and less stable at high speeds, until it flys off the road on it’s own. So… Read more »

I’d like to see how the Fusion energi stacks up against these. I recall hearing they were in the .27Cd range That would put it within the mix of the rest of these I would think, though I don’t know the frontal area.

There is indeed a complex relationship between weight and aerodynamics. If you check the EPA Wh/mile for all electric cars, you will notice that the Tesla S is the only one that uses less energy on the highway than in the city. That is because it is heaviest EV, adversely effecting city driving but also has the lowest effective frontal area, a plus on the highway.

What should be obvious is that the best solution for battery powered cars is to reduce drag AND weight, thereby further reducing the need for heavy batteries…a positive feedback loop.

The ultimate example of this is Cedric Lynch of Agni motor fame, whose lightweight, fully enclosed streamlined motorcycle uses 25-26 Wh/mile at 50-55 mph on normal roads. His 5 kWh pack can take him 150 miles, and could fast charge on a 240 volt J1772 outlet!

The only way to make light, efficient AND inexpensive vehicles possible in our current social/political system may be autonomous vehicle technology. This technology could make average speeds higher with lower maximum speeds, and stop the current vehicle mass arms race. May the killer SUV’s part like the sea for Moses! 🙂