The World of 300+km/h by Daijiro Inada TOP > COLUMN > Daijiro Inada > CASE 2
The Founder of the Option Empire, Daijiro Inada
The World of 300+km/h
CASE 1 The Yatabe High Speed Test Course
CASE 2 The Speed Week in Bonneville
CASE 3 The Autobahn in New Zealand
CASE 4 The Silverstate Classic Challenge

Dai is the founder of Option, the Tokyo Auto Salon, and the D1 Grand Prix. Half of his life was spent accepting high speed challenges. Let's listen to what he has to say about the world of 300+km/h and its history.
Case 2 Challenging the Bonneville
Bonneville refers to the Bonneville Speedway located in the Utah side of the Nevada border. But a speedway course doesn't mean that it's paved at all. A desert of a dried up salt bed is used, called the Salt Flats.
This speed trial began taking place at this enormous piece of land, more than fifty years ago in 1949. For a top speed run of 200~300 km/h, a straight stretch of road is required, and technically, it can be pulled off on a public highway. Back in the days, we have performed high speed runs at the Daytona Beach, the German Autobahn, and even oval tracks but when the speeds started to exceed 400 ~ 500 km/h, these locations were not sufficient. This is when we started going to the salt flats. Here, people can even race jet engine cars going at mach speeds.
Every year in August, when all the salt beds are available, there's an exhibition called the Bonneville Speed Week.
In 1986, a team led by Ryusuke agreed to let me enroll in the FC Seven challenge where I learned a lot about the Bonneville flats. The Option team's first battle was in 1989.
The cars participating was TBO's 130Z (S130) and the Option (D-Speed) 180SX. I was expecting to easily exceed 300 km/h but the Bonneville challenge was not that easy.
First, the radial tires were no match for the Bonneville's salty surface. The vehicle would begin to slip and go into a spin after 250 km/h. Due to the strict regulation conflictions, big aero kits couldn't be installed to hold the vehicle down. Also, the fuel delivery to the engine does not perform up to par in these conditions because of the raised elevation.
The first Bonneville try was a failure since I ended up spinning before I can reach 300 km/h. Despite this experience, the Bonneville challenge and the Yatabe trials had given me hope that the future of top speed runs are bright.
The next attempt in 1990, the cars like the TBO, Central's Z32, and JUN Auto's Z32 accepted the pursuit for 300 km/h. In 1991, JUN Auto's Susumu Koyama trapped in at 421 km/h (261 mph). Wanting to beat his record, I hopped in the vehicle and gave it a shot. The motor ended up blowing at 420 km/h. People like Koyama and Central's(Dandy) Mr. Tanaka were already in the glorious 200 mph club, which too me eight years to join in 1997 with JUN Auto's GT-R at 383 km/h (237 mph).
Bonneville had taught me a lot of things from the air resistance against the body of a car, the relationship between the tire and velocity, aerodynamics, the engine air intake temperature, etc. It's a scary feeling when you don't understand how the forces of speed will react to the machine in those conditions. These valuable experiences will surely improve Japan's tuning skills.
I still love Bonneville. If I decide to challenge it again, I would like to aim for the 300 mph club.
The TBO S130Z and Option 180SX first enrolled in this challenge in 1989. Dai attempted the feat with the TBO 130Z, but the machine was not setup properly failing to achieve an A license. (A license- a license after exceeding 320 km/h).
TBO, Central20
JUN Auto's Z32
At the Bonneville's second attempt, Centra20's Dandy Tanaka set a new world record. The 357 km/h (221 mph) blast labeled him as the first Japanese man to enter the 200 mph club.

New Record: 421km/h
No one had ever attempted a 421km/h run but, surprisingly JUN Auto's Z32 set the new record. Koyama of JUN achieved this with a successful 1000 horsepower setup.

In 1997, Dai in the JUN Auto GT-R successfully enters the 200 mph club. Although he could not reach 400km/h, his best speed was 383km/h.
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