To make yourself go faster in any vehicle while driving (you must let your boost charge), keep tapping X. This will make any vehicle go faster and not use boost.
When you are coming up on the finish line, have your boost meter almost all the way full. When the finish line is fairly close, throw on the boost. Do not stop holding on the boost and your car will began to heat up. After the meter is all the way to the end your car will explode, launching you a good distance forward at an extremely high speed.