Suzuki's inability to fully meet the 1978 emissions regulations with the two-stroke engine compelled them to write a contract with Toyota to purchase engines from their subsidiary Daihatsu, Suzuki's main competitor. Beginning in May 1977 Daihatsu's catalysed four-stroke AB10 engine was installed in the SS11, selling in parallel with the two-stroke at a slightly higher (by ¥18,000) price. Four-strokes had a "4" logo in the grille. These were very weak sellers, offering much less torque and drivability than their two-cycle brethren. Torque was 3.9 kgm at 3500 rpm, versus 4.6 kgm in the smaller two-stroke engine. At about the same time, in an attempt at meeting the tighter 1978 (53年) emissions standards with a two-stroke, the new SS12 Fronte 7-S was presented. It had a now even cleaner T4A engine called the TC53. "TC53" stood for Twin Catalyst, year 53 of the Showa era (1978 in the common era). This new, cleaner engine lost further power and torque though, now down to , and still barely met the official emissions standards. A mere 6421 SS12s were built, compared to 66,540 SS10 Frontes.