BMW S58 Steel Crankshaft by 5150 AutoSport

Replaces BMW part #11218053285

Sold as a part of our 3.4L 5150 S58 Stroker Kit

5150's bully-grade crankshafts are machined from 4340 aerospace grade billet steel on Mazak 5-Axis Integrex 300-IV machines, some of the most technologically advanced CNC equipment available. Every 5150 crank that leaves our machines is quality checked to ensure that it is within the strict .0001" exacting tolerances we demand. 

All 5150 AutoSport Billet Stroker Crankshafts feature large radius journals that add rigidity for the high boost, high RPM, and of course high horsepower applications our customers demand. This is also where material selection becomes crucial; aerospace steel is the same material used to manufacture the landing equipment on aircraft, selected for its longevity and ability to perform under high impact, high stress applications. 

To ensure the best possible oiling and lubrication, the journals of each 5150 AutoSport Stroker Crankshaft utilize gun-drilled, CNC-ground oil holes, shaped like 'tear drops', are polished to a mirror finish, ensuring that each connecting rod bearing is properly oiled for lasting engine life. To ensure the life of the crankshaft itself, every 5150 Stroker Crank will undergo several heat treatments, including:

Stress Relieving: the crankshaft is heated to a below-critical temperature range. This 'relieves' the metal of any residual stresses that may have occurred during forming, straightening, rolling, or during machining.

Nitriding: during a multi-step heat treatment process, nitrogen is diffused into the surface of the crankshaft, effectively hardening the surface.

Shot Peening: the crankshaft is subjected to a cold working process where the surface is struck by 'shot,' or tiny round particles to harden the surface of the metal.

Magnaflux Inspecting: also known as magnetic particle inspection, this is a non-destructive testing process where a magnetic field is used for detecting cracks and flaws in the surface and subsurface of the crankshaft and confirm that it is ready for the intense conditions of a high performance engine.

Finally, to ensure every 5150 crankshaft has high RPM potential, each counterweight is carefully engineered for minimized windage through the crankcase. This means reduced oil resistance, meaning your crank will spin easier and faster through the rev range and extending the rev range.

Does NOT come with bearings! 

11-21-8-053-285

11 21 8 053 285

11.21.8.053.285

BMW S58 Applications:

2 Series

2023-Present     G87     M2

3 Series

2021-Present     G80     M3

4 Series

2021-Present     G82/G83     M4

X3 Series

2019-Present     F97     X3M

X4 Series

2019-Present     F98     X4M