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
Honda Insight mk1 is highlighted today as a future classic. Honda's early hybrid concept was presented before Toyota introduced the Prius. But it is not the hybrid solution that makes the car 'cool' today - it's the futuristic design. Those who drove around in an Insight at the beginning of 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 net weight of over 2,5 tonnes. Stated drag coefficient is only 0,25 cw. It is amazingly the same as the Honda with "fenderskirts", Kamm profile and a hint of "boat tail".
BMW's new electric cars
A cw value of only 0,25 is nothing less than impressive on such a high-built SUV Bmw iX! The xDrive50 has a battery pack of a whopping 105,2 kWh, two electric motors with a total of 523 horses and a range of 630 km according to WLTP combined. Right now, there are approximately 1500 iXs on Norwegian roads. BMW i4, however, 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 gives a decent range of 510 km (WLTP). Two electric motors provide 544 horses with operation on all wheels. If you look at the air resistance, alone, it makes a difference whether you choose the high or low car.
Measured effect of aerodynamics
All it takes is a bit of headwind and a wet road before the range is 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-built and low-built versions, we see that the factory figures for range are affected to a very small extent. This can partly be 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-rise Audi e-tron and the more coupé-like Sportback edition, we see that the difference in range is only 8 km in the Sportsback's favour. We see similar relationships between Volkswagen ID.4 og ID.5, and between Volvo XC40 og C40. Although parts of the WLTP measurements are driven at higher speeds than we have in Norway, the differences in air resistance do not have a significant impact on range. US EPA (Environment Protection Agency) tests all cars in terms of MPG (miles per gallon). A measuring unit has been introduced for electric cars MPGE where the electricity consumption (kWh) is converted to fuel. The cars are tested both in city driving and motorway driving. Here, the difference between motorway consumption and urban consumption can tell how favorably the cars cope with 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 Porsche Taycan with 2-speed gearbox actually achieves further range on the motorway than in the city.
How much is range affected by aerodynamics?
Teaslike.com shows tabular ranges given different speeds. If we choose 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 under favorable conditions. Corresponding figures for Nissan Leaf (unconfirmed origin shared on a forum page) – shows 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 will 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. Air resistance is just 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 ran on the same tires and were rigged up 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%)
Other
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 within Norwegian speeds. A comparison between two different brands/models with similar battery capacity, weight and engine power can give us a clue as to how aerodynamics affect range. Tesla Model Y LR has, for example, 86 km better range (WLTP) than 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 of 0,34 versus 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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