hythe

I did get to an indicated 145 in my previous E60 530i - it's not big and it's not clever and don't try it at home, kids...

Tiago

I not trying to break any speed record I have a E61 535d-M chippped and i'm impressed with its performance. I already made almost 4200rpm in 6th gear and by my calculations (aerodynamics vs gearing) i need about 370hp to do that. As for the speed this means around 290km/h (real speed).
Now, once i'm not an engineear, i'm just curious about the hole stuff around aerodymanics. If i already can go around 290km/h then the 300km/h are my goal. At 300km/h it will be in the league of a E46 M3, E39 M5, N/A Porsches (997 and previous), Maseratis, Ferrari 355, Audi RS6 and RS4... And once i can?t go more with the HP route, it only leaves me the aerodymanic way. If i get a Cx of 0.27 and with the same hp that i have now, i will be possible to reach 4300rpm (300km/h). I'm planning to lower the car and maybe to take off the roof bars (i heard that the roof bars it sacrifice badly the drag). What do you thing?

dlevi67

Not wanting to sound like a spoilsport, Tiago, but have you followed Richard Hammond's recent story? I'm not sure that 300+ is a safe speed in a car that's not designed to do that. The big risk is lack of sufficient downforce and consequent instability.

Tiago

Not design for it??? Is the M5 much more different than M-pack car? There some vids from M5forum.com with M5 at 200mph and they seem very stable. The only main difference to our cars could be only the rear difuser that improve a bit more the downforce. Other than that won't do much. About Richard Hammond accident, 186mph is not 300mph and dragsters has almost no weight compared with our cars. Their weight at high speeds cames due to spoilers and wings and even this add just the enough weight to keep the wheels on the ground, because too much weight means worst runs.

hythe

The major problem will be finding a road long enough. The E61 will always have a bit less high speed stability than the E60, given the long roof (= more rear-axle lift), but in my car it's pretty stable up to these kinds of speeds.

As Dr. Piech discovered with the original Porsche 917, sometimes the ultimate goal in high-speed running is not just minimum drag, but also stability - it's a trade-off, and the trick is to minimise inefficiency.

Personally, I wouldn't try to hit 300 in a car that can only just reach it. You'll need a 5 mile straight and very little traffic. You'll be stressing some components beyond their specified loads, for quite a long period of time. It's really not the best idea.