The Mach 5 (or Mach Go) is a high tech race car driven by Go Mifune in the Mach GoGoGo / Speed Racer series.
The car appeared in Time Bokan: Royal Revival where it almost runs the Doronbo Gang over and later is destroyed by them by their mech.
In Yatterman 2008, Go drives it and uses the "Control C" function which brings out saw blades and slashes the tires to the Doronbo Gang's vehicle to stop them from following Monta Mino around.
In Yatterman Night, Sanpei guards it in an abandoned shed being the only thing left of his old family. Galina and Alouette use it to break the Doronbo Gang out of Abareshi Prison and Sanpei later spends the rest of his days driving it on his own.