The E23 7-series was introduced in 1976 and initially the top of the line car was the 735i. But to be able to compete with Mercedes 450 SEL and Jaguar XJ12, BMW needed a more powerful car. So in 1981 BMW presented the 745i with turbocharger and 252 bhp.
However between 1976 and 1981, Alpina had free reign with the 733i Alpina. It had a 3,2 litre 6-cylinder engine which in standard BMW form produced 197bhp. Alpina fitted forged higher compression pistons, modified the combustion chambers and fitted a new camshaft. They also changed the valve timing and fitted a new special exhaust system. The 3,2 litre engine produced 240 bhp and it is connected to a 5-speed Getrag gearbox.
The changes made to the suspension are shorter and stiffer springs and gas-filled Bilstein dampers. The Alpina alloys are 14in high and 7in wide.
The brakes are uprated too, ventilated discs all around.
The 733i Alpina accelerates from 0-100 km/h in 7,8 seconds and has a top speed of 228 km/h.
When BMW introduced the 745i, Alpina decided to stop modifying the E23 7-series. Alpina did offer a turbocharger upgrade package allowing higher levels of boost.