Mercedes cars and bad drag coefficient

[majidz]

HALLO EVERYONE .... (dc=DRAG COEFFICIENT )
I was looking at the new cars dc ... i found that the best cars in dc are japanese cars specially lexus and infiniti ... and the worst is mercedes ...

e.g. cls 55 dc is .30 ... lexus ls 430 dc is .25 ( with air sup ) ...
SLR has very bad dc ( .37 ) ... while toyota landcruiser suv dc is .35 ...
E 350 dc is .30 while lexus gs 300 ( the new one ) is .27 and the same for the new infiniti m ...
do you think that mercedes do not have the ability to make their cars to have good dc ??
that will save more gas ... and make their cars have good EPA numbers .....







majidz

[cooperluke]

If the SLR had a better DC, it wouldn't have the downforce it has and would take of when you reached 300km/h

[ikon2003]

Ya, I can comment on the SLR's "high" CD as a function of downforce. The enzo and Zonda both have similarly "high" downforce.

Performance cars like these shouldn't be judged on CD alone, but the ratio of Downforce to CD - that's a better indicator of how good the engineering is. Plus, a lot of them have variable CD/downforce via adjustible spoilers (SLR, Enzo) or completely removable body panels (Zonda, Koenigsegg).

For the other cars, yeah, MB is a little higher than the other ones, but i wouldn't say it's a really "high" CD. only when things get over .40 would i start thinking more about it. If you compare these modern cars with ones from 20 years ago, modern ones are so much more efficient aerodynamically.

[pimrusis]

Originally Posted by majidz SLR has very bad dc ( .37 ) ... majidz

Thanks for your opinion, I'm still gonna trust the boys at Mclaren though. Even though you, apparently, know more than them.

[SPEEDKILLAR]

Originally Posted by majidz HALLO EVERYONE .... (dc=DRAG COEFFICIENT ) I was looking at the new cars dc ... i found that the best cars in dc are japanese cars specially lexus and infiniti ... and the worst is mercedes ... e.g. cls 55 dc is .30 ... lexus ls 430 dc is .25 ( with air sup ) ... SLR has very bad dc ( .37 ) ... while toyota landcruiser suv dc is .35 ... E 350 dc is .30 while lexus gs 300 ( the new one ) is .27 and the same for the new infiniti m ... do you think that mercedes do not have the ability to make their cars to have good dc ?? that will save more gas ... and make their cars have good EPA numbers ..... majidz

Bwaaaaaaahahahahahahahhaaa

[Z3uS]

Hmmm ok, If i had money i would´t buy a SLR because of the bad dc :roll:

[majidz]

thanks for everyone came to this subject ...
dc is very important .. cars that have good dc will have good economy and high top speed ...
i ve chalnged with my friend ... he has lexus ls 430 and i brought my brother car chevrolet caprice ( holden capeice ) ... my brother's car lighter and has greater engine ls1 5.7 with great torqe ...
my friend passed me on 120 km ... and he was going fastly ... the different was very big on 200 km .. ( bro car dc = .30 / fri car dc = .25 )
Ronin005 .. you can see this .. for slr

http://www.maximum-cars.com/Cars/Car.php?carnumber=478

and this for toyota land cruiser ... to compare ...

http://www.toyoland.com/trucks/land-cruiser.html

and this for cls 55 ... with .30 ...

http://www.mercedes-benz.ca/index.cfm?id=4339

and here for the great lexus ls 430 with .25 dc ...

http://www.lexus.com/models/ls/specifications.html


and you can compare any lexus car with mercedes one and you will find that the lexus has better dc ...





majid

[Vansquish]

Originally Posted by majidz HALLO EVERYONE .... (dc=DRAG COEFFICIENT ) I was looking at the new cars dc ... i found that the best cars in dc are japanese cars specially lexus and infiniti ... and the worst is mercedes ... e.g. cls 55 dc is .30 ... lexus ls 430 dc is .25 ( with air sup ) ... SLR has very bad dc ( .37 ) ... while toyota landcruiser suv dc is .35 ... E 350 dc is .30 while lexus gs 300 ( the new one ) is .27 and the same for the new infiniti m ... do you think that mercedes do not have the ability to make their cars to have good dc ?? that will save more gas ... and make their cars have good EPA numbers ..... majidz

Lexus and Infiniti do as much as they can to make their cars cruise silently with as little wind-noise as possible. In order to do that, a lot of time and effort is spent on wind-tunnel refinements to smooth the airflow over the car. A "cd" (it is usually referred to as cd -- coefficient of drag -- rather than "dc") of 0.30 is really pretty good for the CLS. Part of the reason that it scores, "lowly" compared to the Lexus LS is because of the fact that due to its sleek shape, there is quite a lot of turbulence that builds up at the interface between the airflow under the car and what flows down off the roof. This is due to the fact that the car in essence resembles an airplane wing in profile. You'll find that the same problem exists with the 911 and the Audi TT to name a couple of others. In the US, the Ford Taurus suffers from the same problem. The only way to smooth the airflow and make the interface between the two airstreams less turbulent is to add a lip spoiler at the rear of the vehicle. On the 96-99 (very ovoid) Taurus, there was a black strip at the top of the taillights that acted as a lip spoiler for precisely that reason. The TT was retrofitted with a little spoiler, and the 911 and Boxster both carry pop-up wings to do the same (and add a bit of downforce at the rear). CLS55 also has a little lip spoiler for the same reason.

In addition, if you are trying to create a lot of downforce there is going to be a lot of aerodynamic drag as well as increased frontal area which contributes to a separate portion of the drag coefficient (and is usually calculated separately as well). The SLR compared to a Holden Monaro would have a significantly higher coefficient of drag, but remove some of the aerodynamic addenda and I bet it's about the same.

[blah]

E500 would spank a LS430 on the top end. Lexus werent meant for top end, they get very scary up there, they get very fidgity.

[MBDriver]

Originally Posted by blah E500 would spank a LS430 on the top end. Lexus werent meant for top end, they get very scary up there, they get very fidgity.

I know what you mean. I took my sisters IS300 for a top speed run early morning one time and let's just say I never want to do that again.