I believe the LS 430 has (or had when it was introduced) the lowest coefficient of drag among sedans- maybe among any car.

 

Yessir it does! Among all cars (but only if it has the optional (i think) "air suspension" offered by Lexus)!

 

Insight is 0.25, I believe LS430's is 0.26. The GM EV1 Electric car is 0.19.

 

The aerodynamics is good inside the car. That's all I care about

 

Would the OEM rear spoiler increase downforce? I bet the Feels would do a good job since it is about 2'' above the trunk. All I care about is keeping the rear end planted. I would like a little more downforce around turns and at high speed since I tend to push the car to its limits (drifting is fun, controlled of course, not too crazy). Although the drag would increase, I think the extra benefits would outweigh the costs.

 

it would at least add a couple lb of down force ...

(old joke )

 

Roadsters are best enjoyed driven hard (but not neccessarily fast) in the twisties. Therefore, I don't think Honda engineers considered the Cd a high priority. I would also not put too much hope on aftermarket aerodynamic addons to reduce drag. It's just not economically feasible to spend the hundreds of wind tunnel hours needed to minimize drag when they can mass produce large GT wings to add down force with little r&d.

BTW, the Passat has .27 Cd.

 

Unless you are making turns at 90 mph or late-braking into apexes after a 150 mph straight on a regular basis, I don't think there is any need to worry about downforce at all. With only 240 horses, I doubt we'll ever have to worry about high speed instability requiring a GT wing. Which makes all these spoilers for our car purely "cosmetic" enhancement . But I happend to like the "bare" look of S2000 without any "attachments"...they seem to put breaks on the smooth lines of our car.

With same reasoning, I would assume the supposedly high drag coefficient is not a problem unless you hit very high speed (~100 mph?) on a regular basis. If Honda really did put a steep windshield just to pay a little tribute to the spirit of S500, that's probably why they did it.

 

[QUOTE]Originally posted by Gymniac
[B] Which makes all these spoilers for our car purely "cosmetic" enhancement

 

The Cd is determined mostly by what goes on BEHIND the vehicle. Yes, the shape of the front does have an effect, but most of the drag comes from how the air is handled behind the car. Ideally, you want to "merge" the air smoothly back together, like an aircraft wing with a sharp trailing edge. Without this, you end up with an area of low pressure behind the car which effectively sucks you backwards. This low pressure is also what traps the dust and deposits it on your bumper... This is why a wagon has much poorer aerodynamics than a sedan of the same model. The fronts are identical, but the abrupt end to the body causes large vortices/flow separation which cause the low pressure region. So with the top down, there's effectively a large, abrupt step which casues a lot of drag. BTW, those vortices are why the air in the cockpit is moving forward.

With the top up, it's still not great... Part of this comes from the surface of the top which is very rough compared to painted metal. Also..the shape still isn't great...