Mazda Capella Rotary Coupe GS II (1972)
Publication: Car Graphic
Format: Road Impressions
Date: June 1972
Author: “C/G Test Group” (uncredited)
Road testing the Mazda Capella Rotary Coupe GS II
Last March, the Mazda Capella underwent a minor change. Then, the “G series” was added in October last year, the choice of an automatic transmission became available, and the existing models were reworked to catch up. At the same time, the lineup of variations was changed to match the Savanna/Grand Familia naming system, and at this time, the highest-end model in the series was born, the Capella Rotary Coupe GS II (Tokyo delivery price: 920,000 yen). We recently tested the GS II over a distance of about 800km.
C/G purchased an early Capella Rotary as soon as the model was released in May 1970, and we used it for about 50,000km as long-distance, high-speed transportation until very recently. We have covered the details in our test report, but looking back now, in contrast to the car’s extraordinary power performance, we repeatedly struggled to improve its extremely unrefined handling, attempting fixes such as widening the wheel rims, replacing the tires, strengthening the dampers, and even changing to a smaller-diameter steering wheel.
In the end, these measures proved effective, and the C/G Capella’s handling eventually became tolerable for sporty driving. But the fundamental characteristics of the car, such as strong understeer and slow steering, could not be significantly changed even with the fitment of Michelin XAS tires, so there was no choice but to wait for more extensive design changes. Our conclusion was that, if its maneuverability could be improved, the Capella would become a much more attractive long-distance tourer.
So, on paper at least, the new GS II, with its stiffer suspension and 40mm lower ride height, should be the Capella that is closest to our ideal. The GS II also comes standard with a 5-speed gearbox, and the engine is slightly more powerful to deal with the vehicle weight of 980kg, which is 5kg heavier than the base GS.
If we focus the results of our tests on the topic of handling, we can say that the Capella has made great strides. Compared to the base GS, the GS II suspension has significantly higher spring rates that are increased by about 23% for the front, from 1.6kg/mm to 2.0kg/mm, and about 35% for the rear, from 2.2kg/mm to 3.0kg/mm. Accordingly, the damping force of the dampers has also been increased by about 50% on both the compression and rebound sides, front and rear, compared to other models. In addition, as mentioned above, the overall height has been lowered by 40mm, and the wheel alignment at the front has also been slightly altered.
The most obvious effect of all this is a reduction in understeer. Compared to the early Capella, where the nose pushed wide endlessly during cornering and the steering wheel had to be turned more and more dramatically, the reduction in understeer that was first observed in last year’s G series (with slightly stronger dampers and wider tires) is even more pronounced in the GS II, and has now been reduced to a level that is standard for this type of car. Therefore, the cornering posture is stable understeer regardless of speed. However, the limit is still not very high, and at a certain point, the rear breaks away somewhat abruptly. In this situation, with the steering that still has an unpleasant feeling of twisting soft rubber at turn-in, and a steering wheel that still has a thin rim and large diameter (which requires a firm grip, making it tiring on long drives), it is difficult to make quick corrections.
Considering the potential of the Capella’s four-link rear suspension, the test car seemed to lose its grip on the road rather early, but half the blame for this lies with the tires. The Bridgestone Super Speed Radial 20 tires (165SR-13 size) that were fitted this time did not feel particularly stiff even at an air pressure of 2kg/cm², which is far above the manufacturer’s recommendation. Their absolute value of adhesion was low, and the sidewall of the outer front tire tended to roll under in downhill corners, where it bears a large load. In C/G’s experience, the Yokohama GT Special XX of the same size seems to offer superior maneuverability (although the ride is quite stiff, even with the standard GS suspension and 1.5kg/cm² pressure). The stiffened suspension itself did not seem to impair ride comfort as much as we feared, and was much softer than the C/G Capella with its rally front dampers and Michelin XAS radials, picking up pavement joints only a little. The body roll, which is still large, isn’t too noticeable in the GS II, but at higher speeds a tendency remains for the car to yaw a little when settling after a bump.
The new gearbox, a 5-speed fully-synchronized gearbox that is exclusive to the GS II, is the 4-speed type (3.683 / 2.263 / 1.397 / 1.000) from the Capella with an indirect gear (0.862) added on top. At the same time, the final drive ratio is lowered to 4.11, so the overall ratios are 15.141 / 9.303 / 5.743 / 4.111 / 3.544 compared to the 14.364 / 8.826 / 5.448 / 3.900 of other Capella models with the 3.90 final drive (the tire diameter is the same). We expected this to improve fuel consumption during high-speed cruising as well as improving power performance, including acceleration, but the results of the acceleration and top speed tests conducted at Yatabe did not fully meet our expectations.
As part of the updates, the secondary jet of one of the four-barrel carburetors was enlarged, the automatic ignition advance was set wider, and the exhaust pipe was partially widened, giving the new engine an output of 125ps/7000rpm (the rev counter is marked yellow from 6500rpm and red from 7000) and 16.3kgm/4000rpm, which is slightly stronger than the previous 120ps/6500rpm and 16.0kgm/3500rpm. However, the top speed was measured at 181.8km/h in a flying kilometer and the acceleration time from 0-400m was 16.7 seconds. The C/G Capella that we tested previously, which was practically a new car at the time that had driven only 2,000km, easily recorded a top speed 187.5km/h and 0-400m in 16.8 seconds.
What we noticed here is that contrary to what the specs say on paper, the engine’s power is clearly reduced, and while it’s fine at low and medium engine speeds, it clearly lacks punch at the top end above 5000rpm. So, while there is less worry about over-revving, even during standing-start acceleration tests, you can’t expect the same explosive dash just before the redline, either. The top speed in fifth gear is reached at about 6700rpm, but if you run into a headwind, you can see the top-end weakness for yourself as the rev counter needle drops 500 to 600rpm all at once. This power loss is probably due to settings to comply with emission regulations. In other respects, however, this is still a rotary engine, and it goes without saying that it is unparalleled in its smoothness and quietness.
The new fifth gear is useful. There is still a lot of torque available in fifth, so it can be used as more than just an overdrive. If you want, you can accelerate slowly from 45km/h (about 1500rpm) without any apparent stress on the engine, so you can safely overtake other vehicles on normal highways without shifting down at all. However, the fifth gear itself emits a loud metallic noise, and because of the quietness of the rotary engine, it is clearly audible along with the wind noise, which is by no means muted. On the rev counter, 100km/h corresponds to 3700rpm in fourth gear, and 3200rpm in fifth gear, while 160km/h corresponds to 5700rpm in fourth and 4900rpm in fifth. But the engine’s low noise level does not change significantly with this difference in revolutions, so in reality, using fifth gear instead of fourth has little effect other than reducing fuel consumption.
To shift into fifth gear, you push the lever all the way to the right and forward in the usual H-pattern against a return spring, but the stroke in both directions is excessive, so to shift up from fourth, you have to first return the shift lever to the neutral position, then pull it hard to the right and then push it forward, making for an exaggerated motion. The Capella’s manual box has always had problems with the capacity of its synchros, as well as the shift feel, and these defects have carried over into the GS II as well. Our test car had just recently been fitted with a new synchronizer ring, making it stiff to operate, but the synchro was still weak and could be easily overcome with quick shifts.
The GS II’s measured fuel economy, an important consideration these days, was poor at 4.8km/l for the test session at Yatabe, which included full-throttle acceleration runs, 5.2km/l in the city, and 6.7km/l on the Tomei Expressway and during a one-day trip to Hakone, for an overall average of 5.6km/l. However, this was the result of our barely using fifth gear, and driving with complete disregard for fuel consumption. As long as you use the car for high-speed cruising, which is what it is designed to do, it is hard to imagine getting results any worse than ours. Naturally, the rotary requires only regular-grade fuel.
There is nothing particularly noteworthy about the interior or exterior of the GS II, other than it is very luxurious, befitting a high-priced domestic sports car. Even though it is a two-door coupe, it retains the traditional Capella good points, such as the rear quarter windows that can be rolled down and the powerful ventilation. Whether the metallic paint (whose shades include a striking purple, as on our test car), the optional tape stripes that can be applied to it, and the strangely shiny vinyl upholstery are in good or bad taste is purely a matter of preference.
Loaded with all these features, the Capella Rotary Coupe GS II is fully qualified to be at the higher-priced end of the Japanese market for this type of car, and although it has lost some of its once-ferocious punch, it is still unbeatable on the highway. As always, the fact that it combines its dynamic performance with the roominess and ride comfort of a practical car is commendable. It is C/G’s hope that in the future, a Capella that combines the GS II’s improved chassis with the “REmatic” JATCO automatic transmission will become a reality, to take full advantage of this model’s good points.