Fighting resistance then and now
03/14/2023
The car has become better and more efficient over the last 100+ years? Yes, but it has not become as efficient as possible. This is due to many things, not least politics, which likes to measure with unequal yardsticks. For example, an electric car does not produce CO2, no matter how efficiently or inefficiently it drives. It is clean. Of course, this is not true, because the electricity that powers the car does produce unwanted CO2 during production (keyword: coal/gas-fired power plants).
Our colleagues at "ams" have already wondered about this unequal consideration and have started to document the efficiency of cars with a new measurement. The question being answered is how much power the engine(s) must produce in order for the car to travel at 130 km/h. The power is needed to overcome the driving resistance, i.e. the air and rolling resistance. The results so far show how far apart modern cars are in this respect. And because " auto motor und sport " took a sporty approach, the values were also compared with the consumption miracle VW XL1.
Well, we thought that this fuel consumption overview could also be supplemented with classic cars. Since neither the measuring equipment nor the vehicles are so easy to find, we have limited ourselves to vehicles from back then that could reach a top speed of around 130 km/h for an initial comparison. The simple reasoning behind this: If the top speed is 130 km/h, then the rated power of the engine corresponds to the power required to reach this speed. Corrections would of course still be necessary in the event of deviations from the standard speed of 130 km/h. On the other hand, the engine outputs back then were probably to be understood as "gross".
This is what the cars from back then and today look like in comparison ("FW" stands for driving resistance; example: the VW XL1 requires 16 kW or 22 hp to reach 130 km/h):
| Vehicle | Year of construction | FW kW | FW PS | Vmax km/h |
|---|---|---|---|---|
| FMR Tg 500 | 1958 | 15 | 20 | 120 |
| VW XL1 | 2015 | 16 | 22 | >> 130 |
| NSU Sportprinz | 1963 | 22 | 30 | 126 |
| BMW 700 Coupé | 1960 | 22 | 30 | 125 |
| Mercedes-Benz EQS 450+ | 2023 | 24 | 33 | >> 130 |
| Cupra Born 170 kW | 2023 | 25 | 34 | >> 130 |
| Skoda Fabia 1.0 TSI | 2023 | 25 | 34 | >> 130 |
| Toyota Yaris 1.5 VVT-i | 2023 | 26 | 35 | >> 130 |
| Renault Mégane E-Tech EV60 220 Techno | 2023 | 28 | 38 | >> 130 |
| Kia Niro EV | 2023 | 29 | 39 | >> 130 |
| Mercedes-Benz C 300 d T | 2023 | 29 | 39 | >> 130 |
| BMW 700 Sport | 1960 | 29 | 40 | 135 |
| VW Polo GTI | 2023 | 30 | 41 | >> 130 |
| Renault 8 | 1962 | 30 | 41 | 125 |
| Panhard Dyna | 1958 | 31 | 42 | 128 |
| Audi A4 Avant 50 TDI Quattro | 2023 | 32 | 44 | >> 130 |
| DKW AU 1000 | 1958 | 32 | 44 | 131 |
| BMW i7 xDrive 60 | 2023 | 33 | 45 | >> 130 |
| BMW 330d Touring | 2023 | 33 | 45 | >> 130 |
| Opel Olympia Rekord | 1957 | 33 | 45 | 128 |
| VW 1500 | 1962 | 33 | 45 | 125 |
| Ford Focus 2.3 EcoBoost Turnier | 2023 | 34 | 46 | >> 130 |
| Toyota bZ4X | 2023 | 34 | 46 | >> 130 |
| Volvo V90 T6 AWD | 2023 | 34 | 46 | >> 130 |
| NSU-Fiat Europe | 1963 | 35 | 48 | 130 |
| Opel Kadett S | 1963 | 35 | 48 | 137 |
| Ford Mustang Mach-E GT | 2023 | 38 | 52 | >> 130 |
| Morris Oxford V | 1960 | 38 | 52 | 130 |
| Genesis GV60 | 2023 | 39 | 53 | >> 130 |
| Skoda Kodiaq 2.0 TDI | 2023 | 39 | 53 | >> 130 |
| Peugeot 403 | 1956 | 39 | 53 | 130 |
| Ford Taunus 12 M 55 hp | 1960 | 40 | 55 | 126 |
| Simca Montlhéry | 1961 | 40 | 55 | 133 |
| Auto Union 1000 SP | 1959 | 40 | 55 | 138 |
| Audi Q5 50 TDI Quattro | 2023 | 43 | 58 | >> 130 |
| Maserati Grecale 3.0 V6 Trofeo | 2023 | 50 | 68 | >> 130 |
| Mercedes-Benz 180 b | 1960 | 50 | 68 | 138 |
| Humber Hawk Mark VI | 1955 | 52 | 71 | 131 |
| Mercedes-Benz G 400 d | 2023 | 70 | 95 | >> 130 |
A few insights can be gained:
- Modern cars are better the more compact they are, the modern SUV obviously does not look good here.
- Electric cars do not perform better than vehicles with combustion engines because the efficiency of the drivetrain only plays a role in consumption, not in power output.
- Old cars can look very good in this table because they typically have a much smaller cross-sectional area, which allows them to conceal poorer aerodynamics. The fact that the FMR Tg 500 is at the top of the table is no coincidence. It offers relatively little resistance to the wind due to its small frontal area. However, it only reaches 120 km/h with 20 hp; if it had to reach 130 km/h, it would probably need 26 to 28 hp.
- Weight plays practically no role in this consideration, but consumption does. Acceleration in particular naturally consumes significantly more energy if the car is heavier. Some of the fuel consumption advantages of modern cars are therefore lost again with today's much higher weight.
- To drive at 130 km/h, which is the maximum speed allowed in most countries, you need surprisingly little power. 40 hp is comfortably enough even for a mid-range station wagon.
- Old cars are usually driven at a more leisurely pace than their modern successors, which is another reason why our classic cars and youngtimers do not consume as much more than their modern descendants in normal use as would be expected due to the still partly primitive technology.
P.S. What do our readers think? We look forward to your comments!
