OT: 5 fastest production cars in test

[PaulMarin]

I would also be willing to bet some numbers on the posted test are wrong, which ones I'm not sure.
For those of you on this thread who are on drugs, I don't blame you, and its ok as long as you aren't driving. Happy New Year!

[luxobarge]

Johann,

I see where you are coming from on the SL-GT2 comparision between 100-200. I approximated the frontal area using the width/height measurements due to lack of info on the CwA on the GT2. At a quick look the A pillars seems to leen inwards at about the same rate on both cars. When you think about it you can see that the Porsches windscreen is less wide than the rest of the car and this must account for the smaller frontal area of the GT2. The 500 kg weight difference should allow the porsche to pull away more assuming that there is only a 14 hp power difference even if the SLs better aerodynamics could help it at the higher speeds of that intervall. A part of this could be explained by the GT2 being slower than what it has been in other tests. AMS has achieved 12,8 to 200 in another test.

I guess we'll have to wait for other tests to see if there was something abnormal about this car/test. It could be that AMG like some other manufacturers we know of sometimes underrates the output of the engine. Unfortunatly many magazines will probably be given the same car to test so if it's the car that is strange we might have to wait awhile for clarification.

Regards/Robert

Originally posted by johann
Robert,

The number I found most suprising is the 0-200 (or more correct 100-200). It is as fast as the 996 GT2. Yes the Cw is higher on the GT2 but the frontal area is bigger on the SL55 AMG (if we assume that it's the same or bigger than SL400). KnightRider assumed that the frontala area was the same (which it likely isn't).

So we may find that the difference in air resistance isn't that big, in fact Cw*A only is 5% worse on the GT2 (0.58 vs 0.61).
Also in speeds up 200 it is still weight/power ration that is most importan and second power vs air resistance. The SL55 AMG's weight/power ratio is 33% worse than the GT2's!

(SL 55 after eating Murcielago for breakfast)

[Mr Janne]

When we´re already discussing the 0-200 km/h times, what about comparing the Murcielago to the GT2. The GT2 has better power/weight-ratio but the Lambo still pulls away pretty easy...

[de Witt]

The numbers do seem strange. The SL55 has a 33% worse weight to power ratio, but yet it is faster. At that speed, weight to power is more important than the amount of horspower an engine has. If the engine doesn't have to waste horsepower on overcoming the weight of the car, it can use the horsepower more efficently.

Alpina is an original manufacturer of cars under German Law.

de Witt

[KnightRider]

I've just read this story in Race stories section. I took a liberty of changing its' format slightly and the smilies are absent, otherwise I couldn't make the quote thing work. I hope Erik doesn't mind that.

Ferrari Modena vs ALPINA B12 5,7 Coupe. Hi guys and Happy New year. This is not my own story but I decided to post it anyway. I have earlier meantioned an B12 that hopefully will end up in Norway, today owned by a friend of ours in Germany. Well a few weeks before Christimas he took the car for a ride and ended up with a Modena in front of him. The Modena floored it and of course so did my friend. The Modena pulled him slightly up until 220 kph.....but then he started to catch up and at 290 kph he used his flash light on the Modena and then continued to pass him...The fun thing was that they actually tolked togehter after the "race" and the Ferrari guy was like " WTF just happend ???? ". He thought is was just an original 850. Gues he was wrong. Anyway just wanted to share this to you guys. Erik

Here's the link to the original thread http://www.bmwm5.com/vbulletin/showt...threadid=12285

Ferrari is
1290 kg, 400 hp, 373 NM, 310 hp / tonne, Vmax "over 295 km/h"
Alpina is
1865 kg, 416 hp, 570 NM, 223 hp / tonne, Vmax 300 km/h

The figures for Alpina are taken from www.clube31.com and the figures for Ferrari from their official website. The only thing I am not sure of are drag coefficients for these cars and I've got no clue why Ferrari doesn't have an exact number for the top speed.
At first Ferrari was pulling SLIGHTLY on him, then the guy started catching up at 220 km/h, then got to him at 290 and passed him having a higher top speed. We are talking about Ferrari having 40% better power to weight ratio here. I am sure it doesn't sound that it was 40% faster. And actually it has lower max speed. So what happened there? I guess aerodynamics plays a greater role than I thought.
Yes, and knowing Erik from other posts I don't doubt his or his friend's story even for a second.

[BlueBiturbo]

Have any of you guys use the Cartest.exe program to test the top speed? The link is :
http://home.earthlink.net/~patglenn/ct.html
Go to the end of page and download the free DOS-based program.

I found that the program is quite useful and entertaining and it worked at least for standard car specs and for most cars except that it calculates the Alpina B10 Biturbo top speed 10 km/h below the official figure.

Pls tell me how the SL55 result is on the program. Acceleration test is not that accurate, but you'll get the general idea.

I posted the link ages ago but nobody bothered to put any comment whether the program is good or not so if you already have it or did try it pls gimme some feedback. Thanks.

Regards,
Taffy

[luxobarge]

And the Murcielago also has much worse aerodynamics. What factors are left. Tiregrip, rollingresistance and gearing? This is too complicated for me. Engineering is not for me. I'll stick to banking.

Regards/Robert

Ps. Taffy, I managed to download the simulator but when I click on the Icon to start it it opens my photoviewing program. Strange. Would be intresting to try it. I think computers are not for me either. Ds

Originally posted by Mr Janne
When we´re already discussing the 0-200 km/h times, what about comparing the Murcielago to the GT2. The GT2 has better power/weight-ratio but the Lambo still pulls away pretty easy...

[johann]

Originally posted by Mr Janne
When we´re already discussing the 0-200 km/h times, what about comparing the Murcielago to the GT2. The GT2 has better power/weight-ratio but the Lambo still pulls away pretty easy...

Most likely the AWD on the Murcielago can be accounted for this.
Getting all these HP to the ground is proabaly much easier with AWD. Gearing may have also affect this.

Cheers,
/Johan

[de Witt]

Does the Murcielago lose horsepower at the wheels because of the AWD system? I have heard from a few Audi S4 owners who would like just RWD because they lose hp at the wheels.

de Witt

[johann]

de Witt,

Generally speaking a AWD car has more drive train loss than a RWD. Also automatics have more drive train losses than manual cars.

It would be more correct to say that a AWD car has more transmissions losses than a similar car with RWD, for instance 996 C2 vs 996 C4 or E55 4matic or E55.

So IRL a AWD car from one manufacturer may have less losses than a RWD car from another manufacturer.

It would be very if manufacturers supplied WHP also since that is what counts.

Cheers,
/Johan