The B7 engine is based on the M30B30 engine from the E9 3.0 CSi. It is extensively modified by adding a turbocharger with maximum 0,85 bar boost. This engine was introduced in the E12 B7 Turbo and E24 B7 Turbo Coupé in late 1978.

The M30B30 engine was purposely selected due to the preferable relation between cylinder bore and stroke, as well as rigidity of the engine block. A development target was set of 100bhp/liter, resulting in 300bhp.

To improve throttle response and minimize turbo lag, a relatively small KKK K27 turbocharger was chosen. Modifications include Zenith-Pierburg DL injection system, Dr. Hartig ignition system, lower-compression forged pistons and hardened exhaust valves. An intercooler is installed, which reduces intake temperature by 50C. A custom resonance-type intake – which is patented – further reduces pressure waves in the intake.

The B7S engine is based on the M30B34 engine from the 735i. It was introduced in the E12 B7 S Turbo and E24 B7 S Turbo Coupé in early 1982.

The B7/1 engine is based on the M30B34 engine from the 528i with 181bhp (135kW) and 240kW. This engine was introduced in the E28 B7 Turbo/1 in late 1983. Modifications include engine block, pistons, connecting rods, intake manifold, cylinderhead, intake and exhaust valves, exhaust manifold, exhaust, intercooler, oil cooler and modified engine management. Camshaft and oil cooling for the pistons are sourced from the E23 745i.

The B7/2 engine is a slightly modified version of the B7/1 engine. Changes include a custom camshaft and modified engine management, which results in slightly higher peak power and torque. This engine was introduced in the E24 B7 Turbo Coupé/1 in late 1983.

The B7/3 engine is a slightly modified version of the B7/1 engine. Changes include a catalyst convertor and modified engine management, which results in slightly lower peak power but higher torque. This engine was introduced in the E24 B7 Turbo Coupé Kat and E28 B7 Turbo Kat in late 1986.

The B7/5 engine is based on the M30B35 engine from the E34 535i. It is extensively modified by adding 2 turbochargers with maximum 0,8 bar boost. This engine was introduced in the E34 B10 BiTurbo in late 1989.

Modifications include forged Mahle pistons, re-balanced moving pieces and re-machined combustion chambers. The new pistons, which have oil-spray cooling of the undersides, are installed with stronger connecting rods. New valves – sodium-cooled on the exhaust side – and a new camshaft are also fitted. The intake and exhaust systems are Alpina’s own production, as well as reprogrammed Bosch Motronic.

The new exhaust manifolds include twin Garrett T25 water-cooled turbochargers with an integrated, electronically controlled wastegates feeding the engine through a huge intercooler, which stretches from just below the kidney grille down to the bottom of the spoiler. The advantage of two smaller turbochargers is that the same air volume is possible as a single larger unit but with much less turbo lag. The exhaust system – manufactured by Boysen – is made of stainless steel and includes six metal-core catalysts.