“Maniacal Midship (MR) FB3S and EXA Twin-Turbo Specs Surge the Bank!” 1983 Merciless Machines Yatabe Full Test ~Part 1~【Play Back The OPTION】

Published : 2019/09/19 15:30 Modified : 2019/09/26 12:28


The 220.86 km/h (about 137.23 mph) max speed, 11.88 secs Zeroyon RX-7(MR)!

Pumped-up souls of the avant-garde! Limitless tuners attack the bank!



At Option Magazine’s Yatabe (high-speed test road of the Japan Automobile Research Institute, aka Yatabe) Max Speed Tests, we did not focus solely on the record-seeking, fully tuned cars.



From unexpected tuners to magical, flamboyant ones, there were many challengers. For our August 1983 issue, we invited the colorful variants to try the Yatabe. We hope you enjoy this throwback–featuring some of the maniacal participants that graced us with their presence that day.





Dissecting Performance & Mechanism


The Flashy & Furious, Come-One-Come-All Test… an OPT Specialty





Rebuilt cars that know no limits are indeed exciting. The excitement further intensifies when they are done in unconventional taste, as opposed to orthodox. Behold, a full motley of methods!



A GC-Level (Fuji Grand Champion Race) Record-Breaker Appears

Savanna RX-7 MR by Capital

Max speed = 220.86 km/h. Zeroyon = 11.88 secs






Shocking looks. The inside was equally surprising. When we heard that this was a MR RX-7, we assumed it would be a crazy one. Our assumptions were immediately destroyed when we witnessed its authentic build on the same level as race cars from the Fuji GC.






When we entered the monocoque frame cockpit, we felt as though we were crawling on the ground. A bare 13B engine sat behind us. However, the cowl was poorly made, and the clear view of the front tires and ground made us uneasy. We jumped as we started the engine; it’s safe to say that the peri-port rotary exhaust noise from the straight muffler almost tore our eardrums.






Shifting with the Hewland trans is similar to that of a race car; a click of the wrist is all you need. The peripheral ported 13B, about 290ps, is said to have a power band starting from 6000 rpm. We revved 6000 rpm at first, second, and third. While small vibrations occurred, there were no abnormalities. Yet, we definitely could have done without the dust from the road flying into the interior.


We gradually increased the revving. The speed was around 200 km/h (about 124.27 mph). Still, the straightness wasn’t bad. We tried to increase to 7000 rpm in 5th, but seeing that the oil and water temperature upsurged we had to stop.






In its shakedown, it marked 220.86 km/h for max speed and 11.88 secs for Zeroyon. This RX-7 may have been a normal car base, but was packed with otherworldly potential–with its mid-engine design on par with a race car. Without a roll cage and cowl reinforcement, however, there was a risk of the entire vehicle blowing away. We still felt an undeniable urge to drive it even more, regardless of its current state. It’s been a while since we got so heated over one car.



Is this really a Kei (smallest highway legal passenger cars)!? A paralyzing speed from mechanical tuning!

Don 633 Mira Cuore (Daihatsu) by Don Enterprises

Max speed = 133.83 km/h (about 83.15 mph), Zeroyon = 18.7 secs






The stylish Mira Cuore is a fun tuning base car. It’s especially charming that they chose mechanical tuning over turbo. This Don 633 kit was also set up with a Solex carb, so the responsive acceleration is satisfying. Furthermore, we could tell this was powerful, without it reaching 50ps.






Despite the rev limit being 7800 rpm, it sped through first, second, and third gears; we couldn’t believe that a Kei was this fast. We were blown away with its ability to constantly hit the 18-second range for the Zeroyon, too. Of course, when shifting up to fourth gear, the acceleration slumped; this is because normal 4-speeds are high geared.


Be that as it may, its max speed boasted around 6500 to 6600 rpm and over 133 km/h (about 82.64 mph). According to the tuner, he was aiming for 140 km/h (about 86.99 mph), which is definitely possible. The fun in driving this car wasn’t in max speed trials, but rather in traffic signal grands prix where it gave compact cars a run for their money.



We won’t lose to a genuine turbo! First Twin-turbo of the 1.5L class! 

Nissan Pulsar EXA Twin-turbo by ATS-BM

Max speed = 207.49 km/h (about 128.92 mph)






A feature of a tuned turbo is certainly its explosive power. At the same time, it’s proven that low-end torque is somewhat of a pain. Whereas this EXA turbo’s boost pressure was 1.5 kg/cm² (about 21.335 psi) and a low compression ratio of 6.8, it effortlessly ran at a low mid speed range. This was because of the twin conversion from a small scale turbine. Needless to say, its acceleration past 4000 rpm was undoubtedly fierce.






However, the clutch slipped beyond 7000 rpm, and there also were issues including being unable to get into fifth gear. For this reason, we could not measure its Zeroyon and tried only for the max speed attack. This was possible with a little clutch playing.


The tachometer reading increased gradually, though around 6500 rpm, it indicated we were running out of gas. This could most likely have been adjusted with the carb settings. Additionally, we were concerned with the unstable suspension when it took the bank. We thought that further improvements were all in all necessary to try the max speed test. Notwithstanding its easy reach over 200 km/h (about 124.27 mph), this machine had high potential. Its 1.5L original engine tuned with Twin-turbo and hidden ability were especially amazing.









Although there were colorful variants with extreme character, they all awed us with their firm high records. Likewise in Part 2, a Toyota Starlet with 13B rotary specification, a nostalgic Honda N360 refined with N500 racing specifications, as well as an RS Turbo Sylvia appear; they will surely exceed expectations!


[From OPTION 1983 August Issue]