BMW B58 Gen1 Steel Crankshaft by 5150 AutoSport

Replaces BMW part #11217643257

Sold as a part of our 3.2L B58 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! 

11-21-7-643-257

11 21 7 643 257

11.21.7.643.257

Applications:

1 Series

09/2015 — 06/2019  F20 LCI
09/2015 — 06/2019  F21 LCI

2 Series

09/2015 — 06/2017  F22
09/2016 — 12/2019  F22 LCI 
09/2015 — 06/2017  F23
10/2016 — 12/2019  F23 LCI

3 Series

10/2014 — 10/2018  F30 LCI
10/2014 — 06/2019  F31 LCI
09/2015 — 12/2019  F34 GT LCI

4 Series

04/2015 — 02/2017  F32
05/2016 — 12/2019  F32 LCI
03/2015 — 02/2017  F33
05/2016 — 12/2019  F33 LCI
03/2015 — 02/2017  F36 Gran Coupé
05/2016 — 12/2019  F36 Gran Coupé LCI

5 Series

10/2015 — 06/2019  G30
03/2016 — 06/2019  G31
02/2016 — 08/2019  G38

6 Series

09/2016 — 06/2019  G32 GT

7 Series

10/2014 — 01/2019  G11
10/2014 — 02/2019  G12

X Series

10/2016 — 07/2019  X3 G01
03/2017 — 07/2019  X4 G02