Audiablo

If you applied identical mods to both cars, including exhaust, etc... stage II or whatever, which would have a better top-speed? The A6 has a lower drag coefficient, so I'd think it would have the edge. Or is there more to the formula?

frank

lower drag, but more frontal area..S4 would go faster

a4turbo18t

One more thing, S4 has less weight too!

THE MEROVINGIAN

When trying to achieve top speed the 200-250 pound difference is not as much as a factor as the lower drag-coeffecient that the a6 has. Botom line, with same power the A6 would top out a little higher than the s4.

Audiablo

I mean, a watermelon with a frontal area of two square feet probably has a lower drag coefficient than a cube with a frontal area of 1.8 feet.

As for weight, that affects acceleration but not top speed. I imagine an A6 carrying five 250lb passengers and 250lb of gear in the trunk would basically achieve the same top speed (albeit in a slower fashion), though as someone said in the A6 forum, increased tire rolling resistance would come into play - but not much.

frank

(Or Something)

Audiablo

I suppose the only true way to tell is to put it to a real-life test :-)