Match your solar power output to a suitable motor.
How to make a solar panel car go faster.
Course the car will run faster in a straight line than in a curve and faster on a flat course than up a gradient all other things being equal.
You can make it a streamlined shape like a racecar.
Window sill for instance by running the car in an open area away from large buildings.
While solar powered cars remain the stuff of science fiction tales for most of us some forward thinking engineers have been building and racing them for years but designing a car to run on solar power is a tall order.
This will reduce rolling resistance.
If the car is powered though its wheels it may go faster than a car that is launched into the air by a bump.
Running surface run your car on a smooth hard surface.
If you can get 3v through a 3v motor and use a suitable gear box available at hobby shops then you should have a quick car.