on another note, if you want to know a good way to accurately guage your cars top speed, you can do so with little other than some duct tape, a tape measure, and a calculator.
first, you put two pieces of tape on the ground 50 feet apart. use the tape measure to do this accurately. then, you drive the car across the two pieces of tape at top speed. have a friend use a stopwatch to time how long it took for the car to cross from the first piece of tape to the second.
divide 50 feet by the number of seconds it took for the car to cross the tape, and multiply THAT number by 0.682
you should then see your cars top speed in m.p.h.
ex: if your car had a time of 0.8 seconds, its speed was 43 m.p.h.