Turbocharging a BMW M50 engine

This page describes the various paths that can be followed in the process of turbocharging a BMW M20 motor, from mild to wild. Most of the information pertains to the M20B25 2.5litre version.The information is arranged thematically, with no guarantee of its accuracy.

Engine block

The BMW M20 motor comes in various flavours: Stock internals have been proven to be reliable at high output levels, with the rods being the weak link if detonation is avoided. At elevated power output, detonation will be unforgiving towards the stock cast pistons. Various options to use for the bottom end are:

Engine block ancillaries:

Cylinder head

Either small intake port (ABF, 9A) or the larger intake port heads (some PL, KR) can be used. Porting and polishing doesn't hurt if done properly. Possible additions:



Engine hardware


Intake manifold

Various options possible when it comes to choosing an intake manifold:



Exhaust manifold

Various options possible when it comes to choosing an intake manifold:



Turbocharger

Use anything suitable for a 2.0-16v motor running a maximum RPM of 7000. The choices are many:



Fueling

The engine can be fueled in an infinite number of ways, but the recommended paths are:


Ignition

Most modern vehicles have very good ignition systems, and the 16V is no exception. Some recommendations: