So here's a thought (and I dont know what I'm going on about) but here it is...

At higher speeds the mass of a car is held back by air resistance. Like wading through soup...

So huge amounts of power are required to force through the airs resistance.

Here's the thought, could you create a forward facing 'shockwave' pulse ahead of the car which 'thinned' the air in front of it... therefore making the car go faster due to less 'resistance'