The BMW 630CS was the only model with a carburettor to be supplied in the E24 model series. It was launched one month after the BMW 633CSi. As a result of the combustion chamber provided with an optimum technical design (hemispherical swirl-action combustion chamber) and a new carburettor (Solex dual-barrel two-phase carburettor), BMW engineers succeeded in increasing the output of the 3.0 litre carburettor engine (M20) to 185 hp. Nevertheless, the production run of the BMW 630CS came to an end in August 1979. The fact was that carburettor engines were no longer state of the art. It was replaced by the BMW 628CSi.