Toyota designed the engine for performance; the valve angle was a relatively wide 50 degrees, which at the time was believed to be ideal for high power production. Today, more modern high-revving engines have decreased the valve angle to 20 to 25 degrees, which is now believed to be ideal for high-revving engines with high specific power outputs. The first generation 4A-GE is nicknamed the "bigport" engine because it had intake ports of a very large cross-sectional area. While the port cross-section was suitable for a very highly modified engine at very high engine speeds, it caused a considerable drop in low-end torque due to the decreased air speeds at those rpms. To compensate for the reduced air speed, the first-generation engines included the T-VIS feature, in which dual intake runners are fitted with butterfly valves that opened at approximately 4,200 rpm. The effect is that at lower rpm (when the airspeed would normally be slow) four of the eight runners are closed, which forces the engine to draw in all its air through half the runners in the manifold. This not only raises the airspeed which causes better cylinder filling, but due to the asymmetrical airflow a swirl is created in the combustion chamber, meaning better fuel atomization. This enabled the torque curve to still be intact at lower engine speeds, allowing for better performance across the entire speed band and a broad, flat torque curve around the crossover point. During rising engine speed, a slight lurch can occur at the crossover point and an experienced driver will be able to detect the shift in performance. Production of the first-generation engine model lasted through 1987.