New electric SUVs don't exactly ooze aerodynamics, but they shouldn't look at the dog's hair. Below is a picture of a brand new high-built car and a 20-year-old aerodynamic marvel for its time. The two cars have amazingly the same Cw value.
THE SECTION BELOW IS BEING REWRITTENTHE AIR RESISTANCE INFORMATION IS NOT CORRECT.
(UPDATED 03.07.2022/XNUMX/XNUMX) /TERJE
Same aerodynamics
The Honda Insight mk1 is being touted today as a future classic. Honda's early hybrid concept was presented before Toyota introduced the Prius. But it's not the hybrid solution that makes the car "cool" today - it's the futuristic design. Those who drove around in an Insight early in the millennium signaled "environmental protection for all the money". Today's BMW iX , on the other hand, is a bulky and heavy SUV - almost 5 meters long, almost 2 meters wide with a curb weight of over 2,5 tons. The stated drag coefficient is only 0,25 cw. It's incredibly the same as the Honda with "fenderskirts", Kamm profile and a hint of a "boat tail".
BMW's new electric cars
A cw value of only 0,25 is nothing short of impressive for such a high-built SUV as the BMW iX ! The xDrive50 has a battery pack of 105,2 kWh, two electric motors with a total of 523 horsepower and a range of 630 km according to WLTP combined. Right now, there are approximately 1500 iXs on Norwegian roads. The BMW i4 , on the other hand, is currently a rare sight. But now it is being rolled out in full. Many have chosen this gorgeous Gran Coupé as their next car. The drag coefficient is 0,24 – and thus on par with competitors such as Tesla and Xpeng P7. The battery pack in the top model M50 is 80,7 kWh and provides a decent range of 510 km (WLTP). Two electric motors provide 544 horsepower with all-wheel drive. Looking at the drag alone, it makes no difference whether you choose the high or low car.
Measured effect of aerodynamics
It only takes a little headwind and wet road surfaces for the range to be noticeably reduced. It is clear that air resistance also plays a role, but it is difficult to quantify in terms of consumption and range. If we consider models that are delivered in both high-rise and low-rise versions, we see that the factory range figures are affected to a very small extent. This can be partly explained by the fact that the test cars are driven indoors in laboratories where the effect of air resistance is calculated – not measured.
If we compare the WLTP figures between the high-built Audi e-tron and the more coupé-like Sportback version, we see that the difference in range is only 8 km in the Sportsback's favor. We see similar conditions between the Volkswagen ID.4 and ID.5 , and between the Volvo XC40 and C40 . Even though parts of the WLTP measurements are driven at higher speeds than we have in Norway, the differences in air resistance do not have any significant impact on range. The American EPA (Environment Protection Agency) tests all cars with regard to MPG (miles per gallon). For electric cars, a measurement unit MPGe has been introduced where the electricity consumption (kwh) is converted to fuel. The cars are tested in both city driving and highway driving. Here, the difference between highway consumption and city consumption can tell how well the cars handle high speeds - and thus give an indication of the aerodynamic properties. The EPA results show that some models withstand high speeds better than others, but there is no significant difference between high-built and lower-built variants of the same make/model.
As a curiosity, it can be mentioned that the Porsche Taycan with a 2-speed gearbox actually achieves a longer range on the highway than in the city.
How much is range affected by aerodynamics?
Teslike.com shows tabular ranges given different speeds. If we choose the 2019 Tesla Model 3 LR AWD with 19 inch wheels, the table shows that the range shrinks by 28,7% by increasing the speed from 100 km/h to 130 km/h in favorable conditions. Similar figures for the Nissan Leaf (unconfirmed origin shared on a forum page) – show that the Leaf mk1 with a 30 kWh battery reduces the range by 32,7% at the same speed increase. Assuming the same driving conditions, the difference between the two cars would only amount to 4% of the range. The Nissan Leaf 1 has a drag coefficient of 0,28, while the Tesla Model 3 has 0,23. Drag is only one of several factors that affect range, such as tire characteristics and weight. Perhaps the difference in range would have been greater if both cars were running on the same tires and were rigged with the same weight? Maybe not? The effect of aerodynamics is difficult to measure in practice.
Cw for popular electric cars
The very best:
Mercedes-Benz EQS: 0,20
Porsche Taycan Turbo: 0,22
Tesla S (current model): 0,208 (In 2012 Tesla S had 0,24)
Good:
Tesla Model 3: 0,23
Xpeng P7: 0,236
BMW i4: 0,24
Comparison:
Audi
– e-tron: 0,28, range: 405 km
– e-tron Sportback: 0,26, range: 413 km (+2%)
With a camera mirror, the drag coefficient is reduced by 0,01
Tesla
– 2021 Model Y LR: 0,25, 70 kwh, range 507 km
– 2020 Model 3 LR: 0,23, 70 kwh, range 560 km (+10%)
– 2021 Model 3 LR: 0,23, 80 kwh, range 614 km
Volkswagen
– ID.4: 0,28, range 514 km
– ID.5: 0,26, range 519 km (+1%)
– ID.4 GTX: 0,29, range 478 km
– ID.5 GTX: 0,27, range 487 km (+2%)
Volvo
– XC40 (408 HP): 0,34, range 421 km
– C40 (408 HP): 0,319, range 437 km (+4%)
Andre
Polestar 2: 0,278
Ford Mustang Mach-E: 0,285
Hyundai Kona: 0,29
Jaguar I-Pace: 0,29
Xpeng G3: 0,29
Hongqi E-HS9: ~0,34
In comparison
Ferrari 488: 0,324-0,330
Conclusion
There is no significant advantage in consumption and range between high-built and low-built variants of the same model/brand – at least not at Norwegian speeds. A comparison between two different brands/models with similar battery capacity, weight and engine power can give us an indication of how aerodynamics affect range. For example, the Tesla Model Y LR has 86 km better range (WLTP) than the Volvo XC40 Recharge 408HK . Since the two models are comparable in terms of battery capacity, weight and engine power, the difference in range can largely be attributed to Volvo's drag coefficient, which is 0,34 compared to Tesla's 0,25.
What is good and what is bad? None of the electric cars mentioned in this post have poor aerodynamic properties. In this company, even the Ferrari 488 would have "high" drag and poor aerodynamics.
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