If allowed in the rules these solid aluminum engine and transmission mounts offer many advantages over a urethane or Delrin mounts. It's no wonder that these mounts have found their way into the top BMW racers in the country. These are machined from solid aluminum and have zero deflection, engine torque will cause a rubber or urethane mount to flex or deflect allowing more torque to passed through the drive line (instead of being wasted winding up the mount). When paired with our flex-free solid transmission mounts you'll get smoother, crisper shifts since the transmission is no longer dancing on the pliable mount. This puts the shift linkages in better consistent alignment. And unlike rubber or urethane the aluminum has zero wear and is not affected by leaking oil or other fluids so this is likely the last set of motor and transmission mounts you will ever need. We very strongly recommend using the solid transmission and engine mounts together as a complete kit, mixing a rubber mount with a metal mount will cause undue stress on the mounting points and will lead to a failure. We never advise using a solid engine mount unless a corresponding solid transmission mount is also used.

These are a no-compromise design for all-out racing use, full solid aluminum mounts should not be used on street-driven cars since there is no material to absorb vibration making these quite harsh for regular street use (track cars don't care about noise).

Product features and benefits:

• Crisper throttle response, positive shifter location, direct power transfer
• Precision machined billet 6061-T6 aluminum housing
• Black anodized for durability and corrosion resistance
• Grade 10.9 stud - fear not, big turbo owners
• Engineered in-house and made in America

This item fits the following BMWs:
2008-2013 E82 E88 BMW 128i 135i 1M Coupe
2006-2011 E90 BMW 325i 325xi 328i 328xi 330i 330xi 335d 335i 335xi - Sedan
2007-2011 E91 BMW 325i 325xi 328i 328xi - Touring Wagon
2007-2013 E92 BMW 328i 328xi 335i 335is 335xi - Coupe
2007-2013 E93 BMW 328i 335i 335is - Convertible
2009-2016 E89 BMW Z4 sDrive30i Z4 sDrive35i Z4 sDrive35is

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.