Quote:
Originally Posted by m-ch
you just downt wanna get it. Let the theorie behind you, get in your car and try it out.
Have you ever try it out..the weight plays a minor roll, your engin is fighting against the drag, thats what slows us mostly down, on the high speed run
What you think will be the factor of drag and factor of weight at hihgspeed to break us down. 10/1, 20/1, i dont know exactly but it must be huge towards the drag.
and again if you have 3 people or 1 people in your car it doesent mattter mutch, ( you cant feel it) on high speed, acceleration, but has a big impact from standstill and lower speed..
coming back to the manhart m6 vs 911 pdk, that just doesnt look at 200hp difference, i do not believe it. Unless this very same car does 0-300 in about 27-29 secs flat, or 100-300 in about 23-26 secs. That must the terrain for the 700hp m6/m5 with 7 speed double clutch..
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So, basically you are saying that Newtons theories is just theories and does NOT apply in the real world?
If you really believe that, then there is no point arguing anymore as you clearly live in a world where the mass of the accelerated body does not matter during acceleration.
Yes, aerodynamic drag obviously is a factor, which I have also explained above. But remember that
both cars will have to overcome aerodynamic drag, so both have to deal with the same forces (depending on Cd). Porsche claims a Cd of 0,31 for the 911 Turbo and BMW claims 0,32 for the M6.
So, even aerodynamic drag is smaller for the 911. The M6 has more weight and more aerodynamic drag to overcome than the 911...
Let's try a different example (assuming similar aerodynamic coefficient of drag for both cars and not considering other factors):
Acceleration from standstill:
100% engine power (F) is used to accelerate the mass
0% engine power is used to overcome aerodynamic drag (Fnegative)
Acceleration from 80km/h:
80% engine power (F) is used to accelerate the mass
20% engine power is used to overcome aerodynamic drag (Fnegative)
Acceleration from 160km/h:
40% engine power (F) is used to accelerate the mass
60% engine power is used to overcome aerodynamic drag (Fnegative)
Acceleration from 250km/h:
20% engine power (F) is used to accelerate the mass
80% engine power is used to overcome aerodynamic drag (Fnegative)
(note that these are just made up numbers and does not represent a specific vehicle)
As you can see aerodynamic drag "eats up" more and more of the engines power, leaving less and less to cope with accelerating the mass of the vehicle.
In the example at 250km/h above the Porsche would have 100hp available to accelerate the cars mass (20% of 500hp = 100hp). Do you seriously suggest that 300kg extra doesn't make any difference for those 100hp that is available to overcome the mass of the car?
The MHR M6 would have 140hp available (20% of 700hp = 140hp).
Power to weight ratio in this scenario:
Porsche 100hp/1600kg = 0,0625
MHR M6 140hp/1900kg = 0,073 (Stock M6 would be 0,059 in this scenario and that also explains why that gets beaten by the Porsche)
So, the MHR comes out slightly ahead of the Porsche on power available to accelerate the mass of the car at 250km/h. Which coincidentally also matches the results in the race between them... (and don't forget that the BMW actually has more drag resistance than the Porsche so it needs even more power to overcome the aero drag...)
So, if aerodynamic drag is something both cars have to overcome in equeal measure (or rather, the BMW more than the Porsche). Then, what is the remaining factor that is different between the two cars? Oh, yeah.
Weight!!!
Put a small trailer that weighs 300kg behind the Porsche and see what happens (in a real world situation)...