previously only the highest-tuned engines were upgraded in this way. This made the A-Plus engines generally longer-lived than the standard A series, which had a life between major rebuilds of around in normal service. Studies were made into upgrading the engine to use five main crankshaft bearings but the standard three-bearing crank had proven reliable even in high states of tune and at high engine speeds, so it was not deemed worth the extra funding. The new engines received distinctive 'A+' branding on their rocker covers and the blocks and heads were colour-coded for the different capacities: yellow for and red for engines. 998 Plus The A-Plus version of the motor was produced from 1980 to 1992. Applications: 1275 Plus The larger engine was also given the "A-Plus" treatment. This lasted from 1980 to 2000, making it the last of the A-series line. 1275 Turbo To allow the MG Metro to compete with larger, more powerful hot hatchbacks a turbocharged version of the A-Plus was developed with the assistance of Lotus Engineering. A Garrett T3 turbocharger was fitted along with a unique SU carburettor with an automatic pressure-regulated fuel system. The engine block, cylinder head, pistons, crankshaft and valves were all modified from the standard A-Plus engines. The turbocharger was fitted with an advanced two-stage boost control system which only allowed full boost to be achieved at engine speeds above 4000 rpm - this was to prevent damage to the sump-mounted four-speed gearbox, the design of which dated back to the early 1950s and could not reliably cope with the high torque output of the Turbo engine at low speeds. The quoted power for the A-Plus Turbo was although in practice the tune could vary from car to car and, because the engine was not intercooled power varied significantly depending on the weather. The MG Metro Turbo was entered in the British Touring Car Championship in 1983 and 1984, with the tuned engines producing in excess of . Turbo versions lasted from 1983 to 1990. Applications: 1983–89 MG Metro Turbo, at 6130 rpm and at 2650 rpm 1989–90 Mini ERA Turbo, at 6130 rpm and at 3600 rpm 1275 MPi A special "twin-port injection" version of the engine was developed by Rover engineer, Mike Theaker. It was the last A-series variant, produced from 1997 to 2000. Few changes were made to ensure the engine complies with Euro 2 (later Euro