At IAA 1978, Alpina introduced the B6 2.8 as well as the B7 Turbo and B7 Turbo Coupe. With these introductions, Alpina made a major step towards becoming a car manufacturer.
As mentioned earlier, the B6 2.8 is based on the 323i with a modified 2.8 litre six cylinder engine from the 528i. Alpina further modified the engine with forged Mahle-pistons, modified combustion chambers, increased compression as well as a new fuel injection system, made by Zenith-Pierburg-DL. The main focus of these modifications was not only to increase power but also to improve fuel efficiency. The BMW 2.8 engine - which in stock form is rated at 177hp - now produced 200 bhp with torque of 248 Nm. The 323i´s original four-speed gearbox was upgraded to a Getrag five-speed unit.
In August 1981, the B6 2.8 received a more highly-developed induction system which made the 2.8 litre six cylinder produce 218 bhp, exactly the same as BMW´s 3.5 litre engine.
For the B6 2.8, Alpina fitted the suspension with new Bilstein struts with gas-pressure shocks and shorter/stiffer springs from Ahle. The 15in Alpina alloy wheels are 6″ wide with 195/50 tires at the front and 7″ wide with 205/50 tires at the rear. The front brakes are uprated with ventilated, drilled discs however the solid discs at rear are retained from the standard 323i.
Inside the front seats were replaced with Recaro bucket seats with much better support. The steering wheel is covered with leather and is made by Momo. The instruments were modified with red needles and (obviously) a higher speed range. Furthermore the B6 2.8 sports a front spoiler, rear spoiler, Alpina wheels and the optional Alpina stripes.
Even by today’s standards the B6 2.8 is still a fast car. For the 200bhp B6 2.8, Alpina claimed 7.5 seconds from 0-100 km/h however independent road testers found the time to be closer to 6.9 seconds. The B6 2.8 has a top speed of around 225 km/h. In performance the B6 2.8 could compete with much more expensive sports cars of its time such as the Porsche 911 3.0.
For the 218 bhp B6 2.8, Alpina claimed a 0-100 km/h time of only 7 seconds and a top speed of 229 km/h.
The production of the B6 2.8 started in March 1978 and ended in January 1983 with the introduction of the E30 3-series. A total of 533 cars were built.