The Fastest Car on Earth (Part 1)

At midnight in a cemetery, the GRX race car engine is unearthed. The following day Spritle and Chim Chim are lured into a truck and trapped. It takes them to Oriana Flub's house, where Chim Chim is tied to a motorized go-cart. When the chimp comes to a stop, one of Oriana's men sprays a "formula" at him. As he takes off again, Oriana announces that "they'll win the Grand Prix of the Orient."

At the track, a new race car comes on the scene. Pops recognizes the sound of its engine. High in the stands, Oriana and her right-hand man, Omar watch while a thug sprays the driver of the mysterious car with the formula. At Oriana's house, Pops accuses her of stealing the engine "out of the tomb of Bent Cranium," the engine's inventor. Pops adds that five test drivers and Cranium died because of the GRX. Oriana knocks him out with "sleeper gas."

Meanwhile, Speed in the Mach 5, along with Trixie and Sparky, follows a flatbed truck carrying the GRX race car. Inside the truck's cab, the man on the passenger side is desperate for water. After he gulps several mouthfuls, he becomes delusional and begs the driver to slow down. The truck pulls into Oriana's garage. Spritle and Chim Chim, who have been lurking in the bushes, spot Speed on the truck. In another room, Pops is being beaten.

In the garage, Speed discovers the famous GRX engine. A man named Curly appears. A fight ensues. Meanwhile, Spritle and Chim Chim rescue Pops, who's tied to a chair. Speed knocks out Curly. As if hypnotized by the car, Speed gets inside to "try it just once." The high speed takes Speed into another dimension and he passes out.

Trivia
It is interesting to note how time has passed the "Fastest Car on Earth" by. At the time this episode was written (1965) speeds in the 150-160 mile (240-256 km)/hr were about average and yet today drivers at Indianapolis have been driving near GRX speeds (230 miles/hr) for most of the 1990s without any major problems. Also if one looks at the Indianapolis 500's site one finds Arie Luyenyk (who holds the records for race speed, one-lap, and four laps) has reached 237.498 mile/hr (380 km/hr) just 20 km/hr shy of the GRX's maximum speed on the speedometer. 

Continuity Errors
We see the speedometer of the GRX and according to it the GRX  supposedly maxed out at  400 km/h (250 mph) which is half of the 500 m/h  speed claimed for the  Mammoth Car

 Cast
 * Peter Fernandez: Speed Racer, Racer X
 * Corinne Orr: Trixie, Spritle Racer, Mom Racer
 * Jack Grimes: Sparky, Chim Chim
 * Jack Curtis: Pops Racer, Inspector Detector