M50

UPGRADES

INTAKE

For most Stage 0.5-1.5 M50, an upgraded drop-in filter is usually perfectly fine and offers a similar power gain to a full intake system. At higher power levels, upgrading the intake system will be more worthwhile.

EXHAUST

The stock exhaust manifold is relatively good for OE. Upgrading this component is still a worthwhile investment, and can reduce weight, temperatures, and overall engine efficiency.

A cat-back exhaust offers the least gains in comparison to intake and exhaust manifold. 57-76 mm (2.25-3 inch) diameters are ideal, though there is minimal difference beyond 65 mm (2.5 in) diameter at lower modification levels. Please consider the weight difference to power gain and decide what works best for you.

HEAD

CAMSHAFT

Read the camshaft page for more information.

VALVETRAIN

+1 mm oversized valves are a worthwhile upgrade. If you plan to rev high, the most important upgrades are valve springs and rockers.

FORCED INDUCTION

You can expect between 6-12 Hp per pound of positive pressure added for most forced induction setups. All M50 variants are able to handle 6-8 PSI relatively well without any internal modifications. With just ARP head studs and a quality head gasket, an otherwise stock M50 can handle 12-15 PSI relatively well.

A tuned Motronic 3.1 ECU can handle 450 WHp relatively well without any sensor changes or large modifications.

The B25NV MAF (Mass AirFlow Meter) is scaled to handle a maximum of about 280 WHp.

The B25TU MAF is scaled to handle a maximum of about 330 WHp.

A common upgrade is the M60 MAF, which is scaled to handle nearly 400 WHp.

B25NV

Colloquially known as the M50B25NV, this model is not equipped with VANOS.

B25TU

Colloquially known as the M20B25TU, this model is equipped with VANOS.