Tideas said:
yeah but isn't that effect minimal? Tractor trailers on the highway tend to go like 50 mph, so they can't pull your car that much can they?
Of course it's more pronounced with speed, but the lead car is indeed pushing air out of the way at any speed. What actually happens at much higher rates of speed is that the lead car is pushing the air out of the way, thus creating less resistance on the following car. Since car 2 is receiving less resistance, less drag, it doesn't need as much power as the lead car to push that air out of the way. So, what do you do with this power? Put good use to it, build up your speed in it's wake so you can slip to the cars side with that extra oomph and speed you have and thus maybe pull past them while they're suffering and you have the higher rate of speed.
Now, of course this is more used in races like Nascar for example since all cars are supposedly to same spec as far as aerodynamics go, so when they go side by side, they're subjected to nearly the same amounts of resistance and the speed car 2 has will usually take them nose to nose with the lead car, and beyond if they have someone trail them. This opens another can of worms as 2+ cars bumper to bumper will split the air better and carry more speed than say a loner off to the side.
Anyways, this isn't a given factor all the time though in real life, as the lead car may have a better coefficient than the other car trying to make that pass at the extreme limits of their bands and since so, actually pull away from the other car going side by side faster.
Drag is a serious factor though. I remember when that ugly ol toyota (or was it the honda) hybrid hit that there was a competition to see who's driving style would yield the best mpg. One magazine group actually had a huge track van "escort" them on the interstate portion of the event. What that did was the above mentioned ability, thus the car used less power to travel at the same speed, resulting in less gas used. They won that segment.
And, next topic, while I'm a purist and like shifting the cogs myself, I'm curious to see Mitsu's new SST in use. Supposedly it shifts faster than humanly possibly, and also stays perfectly in the cars powerband (though it can get confused but you can override it with a flick of a paddle). In fact, in tests, the MR beat out the manual GSR model (which beat the STI) by a decent margain. This tranny shouldn't get confused with your standard "auto-stick" affair that's in your minivan though. It's purpose dual-clutch built.
