Is there anything restricting the top speed of cars?

A computer chip connected to your motor... You can upgrade them if you would like. I know ebay sells them.

To bluntly answer your question: Yes! All cars are restricted by

horsepower, gearing, weight, and aerodynamics. The more aerodynamic a car the better its potential for a higher top speed. Aerodynamic drag plays the biggest part in limiting a cars top speed. After that is horsepower and gearing. Some cars even have a speed limiter built into the car that shuts off the fuel at a certain speed. The car manufacturer may think it is unsafe to go any faster than there predetermined top speed so they "won't let you".

Yes, but it depends on the car. Some cars have functions in the computer that limit either the maximum speed or the maximum engine RPM. Other cars are simply limited by the laws of physics - they reach a point where the engine can't make enough horsepower to keep going faster.

i own a shop ,and the one main thing that everyone seems to forget from time to time is the gear ratio they have with out the right gear there is a limit to what any car will do,that's why the nascar cars run such high speed gears,put an street gear in them and the wouldn't do over 120 miles per hour wound as tight as you could get them,but even if it didn't have a chip in the computer,it would still have a limit on how fast it could go,good luck i hope this helps.

The cars comupter acts like a govenor. It limits rpm's and top speed. You would need a programing tool to change the factory settings.

Some cars have limiters. My 98 nissan 240sx had two. One was a wire from the gagues to the ecu telling the ecu how fast i was going and to stop me from exceeding 118mph. Well after that wire was cut there was a sensor on the transmission preventing me from exceeding 6000rpm in 5th gear. Then I disconnected that. My speedometer only went to 120mph. Wonder how fast i was going...

Electronically governed....means the engine's management system will read your rpms...and start cutting spark to alternating cylinders in an alternating fashion....this is done to keep you from going too fast....the US govt requires cars to be governed to 155MPH...people bypass this function all the time.

Other cars are governed by aerodynamics....

Yeah the speed limit!!

resistence of air. abread truck with a thousand horsepower engine would still probably go slower than a normally aspirated lambo. lambo has better airflow than the bread truck. same reasoning for airplanes the slicker the airstream the faster it can go.

Yeah the computer it shuts down at a certain speed