Assuming you have an electric car that can go 100miles at 70mph on a single charge, what kind of range could you get with the following configuration? An electric car that runs of the main battery bank. Vents on the outside of the car funnel air to a Tesla turbine while the car is in motion. The Tesla turbine recharges the cars main battery bank. I'm not asking if the car will run forever, I'm wondering what kind of range extension, if any, would the car get from the Tesla turbine?

Probably end up with negative numbers... to run that you induce drag... drag decreases efficiency and increases consumption far more than any trivial amount you might generate.

Remember basic physics... for every action there is an equal and opposite reaction.

smoothy is correct. The extra drag that is created by the turbine cannot be made up for by the energy output of the turbine. Consequently the car's range would be reduced.