When the E21 3-series was introduced in 1976, Alpina immediately offered a choice of four different engine upgrade packages. These engines were based on existing upgrades developed by Alpina earlier for the BMW 2002. After BMW launched the 323i and Alpina started having commercial success with the B6 2.8, most of the four cylinder engine packages were discontinued.

The four cilinder engines offered by Alpina were A1/3 (120 bhp), A2/3 (150 bhp), A4/3 (160 bhp) and A4S/3 (170 bhp).

These upgrades were similar to the earlier versions fitted by Alpina to the 02 series cars, with only small changes. The versions for the 3-series were identified by their “/3″ designations. All these early engine upgrades were installed either at Alpina or at approved distributors.

Alpina also produced the C1 2.3 with a 6-cylinder engine. It had a 170 bhp engine and its performance was equal to the A4/3 however the C1 2.3 had considerably greater refinement. Even after BMW started offering the 323i there was a market for the C1 2.3 as the delivery times for the 323i were several months at first.

On a number pictures on the Images tab is depicted a very rare model, a C1 2.3 based on a Baur cabriolet.