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Aerodynamics - boxy is better 📦🦾🇸🇪
I am sure this will put a smile on some faces 😉
Picture from: volvo850spiritclub
Picture from: volvo850spiritclub
Somewhat misleading, but does prove a point!
Very true! On the surface, it presents a fact that is probably very surprising to most people because 99% of people probably don't know how aerodynamics work and how Cd is measured.
Take for instance: tire width is a significant contributor of coefficient of drag. The Lamborghini and Ferrari have unusually wide tires. Whereas the Volvo is probably a 225mm wide tire...
The 850 will come with 195 or 205 from the factory…
The tire width will also impact the frontal area that you need to multiply with the Cw for the drag 😊👍🏻
cross-sectional area matters
The drag coefficient (Cd) number has to be multiplied by the cross-sectional area.
The Volvo's Cd has to be multiplied by its (larger) cross-sectional area, whereas the sports car would seem to have a smaller cross-sectional area.
Therefore, the boxy car is not necessarily a more fuel-efficient car. It depends on your basis of comparison. If the basis is getting one person from A to B, the sports car might still win out. But for getting 4 adults and a dog, the Volvo wins, paws down. But we kind of aready knew that intuitively.
If your basis of comparison is interior volume, then a thin shape with a higher Cd may still be more efficient than a boxier shape of the same interior volume, because it has a smaller cross-sectional area.
Wouldn’t be so sure that it’s not hat clear cut…
The Volvos are a tad taller but also much narrower and have drastically narrower tires, which also impact the frontal area 👍🏻
Would need to check…
But as said above, the Volvos are narrower, if taller, so not so clear cut 👍🏻
It’s misleading because it’s incomplete
The key stat is the the drag coefficient times the cross sectional area. Thats called the “drag area”
That Volvo might have a Cd of 0.32 but its drag area is around 0.32 x 2.5 = 0.8 sqm
The Countach has a Cd of 0.42 but due to a smaller cross section, it has a drag area of 0.84 sqm, not far from the Volvo.
The other sports car (F40?) is almost certainly below 0.8 sqm drag area.
Bottom line: compare drag areas, not bare Cd
That Volvo might have a Cd of 0.32 but its drag area is around 0.32 x 2.5 = 0.8 sqm
The Countach has a Cd of 0.42 but due to a smaller cross section, it has a drag area of 0.84 sqm, not far from the Volvo.
The other sports car (F40?) is almost certainly below 0.8 sqm drag area.
Bottom line: compare drag areas, not bare Cd
That is the more correct viewing indeed 👍🏻
But many sports cars generate a lot of drag because next to the high Cw that they need for cooling and downforce, they are also very wide, so the frontal area is not that small, either 👍🏻
I never really was bothered about specs like this either I liked how a car drove or I didn't.
Marc
Indeed back in the day and the Volvo 850 T-5R was an awesome car as was the one that followed the 850R the most un Volvo Volvos
Marc
We still have a T-5R in a garage but hasn’t been used in anger for years 🤷🏻♂️
Here was the last major road trip with it: www.watchprosite.com
Aha. I've always known that my Jeep Wrangler was way more aerodynamic than those hot dogs in those Ferrari's. lol.
Doesn't corner quite as well though.....hmmmm