BMW Engine Parts

The factory VANOS exhaust hub on the S54 engine is known to develop excessive play where the drive tabs interface with the oil pump disk. Over time, this imprecise fitment causes a back-and-forth rattling motion that can result in the tabs shearing off inside the engine, risking catastrophic damage or complete engine failure. Unlike other aftermarket solutions that require full VANOS disassembly, retiming, or replacement of the oil pump disk, the Turner Motorsport S54 VANOS Hub Upgrade offers a smarter approach. Our bolt-on fix eliminates the common failure point without opening the VANOS unit or disturbing engine timing.

Our solution involves removing the worn tabs from your stock exhaust hub and installing our precision-fit replacement, which is precision-machined from 4340 steel and hardened to meet OEM specifications. Designed using 3D scanning and CAD modeling, the Turner Motorsport VANOS Exhaust Hub Upgrade provides a tight, interference-free fit into the oil pump disc, completely resolving the issue without unnecessary labor.

Features & Benefits:

Direct bolt-on solution for S54 VANOS oil pump drive tab failure, preventing potentially catastrophic damage to engine internals Precision-machined from high-strength 4340 steel and heat-treated to match OEM specifications Designed using 3D scanning and CAD modeling to ensure precise fitment within the OEM oil pump disc Engineered to eliminate the play that exists between the exhaust hub and oil pump disc from factory Backed by extensive real-world testing and our lifetime replacement program!

If you own an M57-equipped BMW, you already know this twin-turbo diesel powerplant is an absolute torque monster. What you might also know is that all that low-end grunt and high-compression diesel vibration wreaks absolute havoc on your accessory drive system.

From the factory, both the E90 335d and E70 X5 35d utilize a rigid alternator pulley. With each cylinder's fire, the crankshaft experiences a violent micro-acceleration. Because the alternator has a heavy internal rotor spinning at high speeds, it wants to keep spinning at a constant rate. When the engine suddenly slows down (even minutely between firing cycles), the alternator fights the belt. This constant tug-of-war results in extreme stress on your engine's belt-driven components. At best, it’s an annoying, unrefined chirp at idle; at worst, it’s a ticking time bomb for your expensive harmonic balancer.

To solve this issue, many enthusiasts choose to run a clutched alternator pulley (also called an overrunning alternator pulley). A clutched pulley allows the alternator to "freewheel" or coast when the engine slows down, completely isolating its rotational inertia from the belt drive to prevent component wear. While the N52's clutched pulley (12317560483) is a straight bolt-on, the offset is incorrect for the E90 335d's accessory drive. Thankfully, our engineers designed this zinc-coated spacer to provide the precise amount of spacing needed to perfectly align the new pulley with existing belt drive components.

If you own an M57-equipped BMW, you already know this twin-turbo diesel powerplant is an absolute torque monster. What you might also know is that all that low-end grunt and high-compression diesel vibration wreaks absolute havoc on your accessory drive system.

From the factory, both the E90 335d and E70 X5 35d utilize a rigid alternator pulley. With each cylinder's fire, the crankshaft experiences a violent micro-acceleration. Because the alternator has a heavy internal rotor spinning at high speeds, it wants to keep spinning at a constant rate. When the engine suddenly slows down (even minutely between firing cycles), the alternator fights the belt. This constant tug-of-war results in extreme stress on your engine's belt-driven components. At best, it’s an annoying, unrefined chirp at idle; at worst, it’s a ticking time bomb for your expensive harmonic balancer.

To solve this issue, many enthusiasts choose to run a clutched alternator pulley (also called an overrunning alternator pulley). A clutched pulley allows the alternator to "freewheel" or coast when the engine slows down, completely isolating its rotational inertia from the belt drive to prevent component wear. While the N52's clutched pulley (12317560483) is a straight bolt-on, the offset is incorrect for the E90 335d's accessory drive. Thankfully, our engineers designed this zinc-coated spacer to provide the precise amount of spacing needed to perfectly align the new pulley with existing belt drive components.