You can find a ton of tips and tricks online regarding how to make the fastest Pinewood Derby car. Search on Google and YouTube to find some great resources and Do your research before you begin!
Here is a great article in Boy's Life to help get you started:
In additon, below is a compilation of some other tips and tricks to help you out. Just be sure you read our official Pack Rules and stay in compliance!
General Design Tips
1. Have your Scout draw a design on paper then cut it out and use it as a template. I use the paper with the little squares on it to make it easier for him. Draw a side and top view on the paper by tracing around the block of wood.
2. Keep the car a full seven inches. It has to do with the physics of velocity and length of travel of the weights.
3. Use the full 2 3/4 inches (outside wheel to outside wheel) that the rules give you. This will allow the wheels to travel farther before hitting the center strip.
4. Leave a lot of wood in the back to put in the weights.
5. Use the groove closest to the end of the block of wood as the rear axle.
Note: The Race Starter will place the car on the track according to axle location. The back axel is nearest to the end of the car. The front axel is furthest away from the end of the car. This determines the direction the car will race unless the contestant clearly marks "Front" on the car.
6. Do not make the front of the car pointed. It is hard to set up against the starting dowels.
7. Use your imagination. Be creative. Shape has the least to do with winning. A beaver driving a log or even a pickup truck is more interesting than a wedge and will be just as fast. The aerodynamics of a small block of wood doesn't mean much in thirty feet.
Tips to Going Straight
1. Put the axle in at a downward (5-10 degrees) angle. This provides two benefits. The first is the only the inside edge of the wheel is in contact with the track. This seems to make the car go straighter with less wobble. The second benefit is that the wheel rides to the outside of the axle and doesn't come in contact with the body. This tip is for experts only. First timers have trouble getting this right. If you have to email me to ask about it, you shouldn't do it.
2. Axles must be in straight front to back. That is square to the body. True the axles, don't trust the slots! If you have one, use a drill press to ensure all axles are straight. One of the front and two of the back should be measured to be the same height.
3. After pressing in the axles, test the car for crooked wheels...roll it on the floor. If the wheels are on straight, the car should roll 8-10 feet in a fairly straight line. Should the car turn left or right, you need to tinker with the axle placement without removing them from the car body, until it rolls straight.
4. Do not put the axles in at the top of the groove. Put them in at the middle. This lifts the car off the track a bit more and reduces the chance of rubbing on the center strip.
5. Glue the axles in place. Nothing is worse than having the wheel fall off as you cross the finish line.
6. Once you match a wheel and axle together with graphite, keep them together. They wear into each other as a matched set.
Be Race Day Prepared
1. Have extra axles and wheels on hand. You never know when your car may be the one dropped by your son as he shows off his handiwork.
2. Have a derby tool kit handy. It should include superglue, sandpaper, a drill, extra screws for your weights, extra weights, a small screwdriver. You may not use it, but it will make you the most popular person at the event.
3. Transport your car in a shoebox. Dropped cars are unfortunately a too common experience.
4. Add LOTS of graphite right before check in.
5. Explain to your son that running the car along the floor prior to the race will cause it to lose!