All you need to build Lego racing cars is your imagination and a bunch of Legos. The only specific type of Legos you need are wheels. It is all about crafting a design that is streamlined and looks like it is built for speed. Here are a few tips on how you can do that.
Start with the Lego racing car wheels. Any Lego wheels will do, but the best are big thick tires because they resemble real race car tires. Connect them with axles or use a flat Lego to hold them together if the wheels are attached to individual blocks. Naturally you will need two axles with two wheels each.
Build the Lego racing car body. Long and flat Lego pieces are ideal for this. To create a racing car frame, make the front long and thin and the rear wider. Attach the axles and reinforce the frame with block Legos. These should overlap the junctures and gaps for strength. If possible, try to make all the blocks the same colour.
Add an engine to the Lego racing car. On Formula 1 racing cars the engines are in the rear. Build it up behind where the driver will sit. Lego pieces with one smooth, sloped side are ideal for the streamlined look of a racing car engine.
Construct spoilers for your Lego racing cars. Make one for the front and one for the back. The rear spoiler should be raised. It sits above and behind the engine. The front spoiler goes in front of the front tires. It should be as low to the ground as possible. Use smooth, flat Legos on the spoilers for an aerodynamic look. Side flaps on the spoilers are also a nice touch.
Accent your Lego racing car with stickers. You can use any stickers. You can even cut out designs from magazines and attach them with clear tape. Little details like these really add to the authenticity of Lego racing cars.
Finish off your Lego racing car with a driver. If you have any Lego characters you can place them inside your race car. If you don't want to create a hole for the driver to sit in just attach his head. It looks just as cool and no one will know the difference.