L6 ASW Serpentine Pulley Kit with ATI Damper Hub — Japan Import

One of the most overlooked problems on high-performance L6 builds running an ATI Super Damper is the pulley ratio. The ATI dampers sold in the US do not include a correctly sized pulley — the pulley is significantly smaller than stock, which means the water pump and alternator require high RPM to reach adequate speed. For a dedicated racecar that regularly sees 5,000+ RPM, this is manageable. For a street car or a build that spends time at lower RPM, it’s a real problem.

A specialist shop in Japan has engineered a proper solution: a complete serpentine pulley kit with a new machined hub and correctly proportioned pulleys that restore the proper drive ratio. The result is correct accessory speed across the full RPM range, plus the added benefit of a serpentine belt system — which significantly reduces belt slippage on high-horsepower motors compared to a traditional V-belt setup.

Kit Contents

• Serpentine belt pulleys — machined in Japan with correct drive ratio for water pump and alternator
• New machined hub for the ATI Super Damper
• Beryllium sleeve for the damper hub — soft enough to protect the crank snout, harder and more durable than brass to resist wear and maintain roundness

Why Beryllium?

The sleeve material is a critical detail. It needs to be soft enough that it won’t damage the crank snout during installation or removal, but hard enough that it won’t deform or go out of round under load. Beryllium hits that balance precisely — it’s a material choice that reflects the engineering rigor behind this kit.

Availability Note

We intended to purchase this kit for our own engine build, but it is currently out of stock. The manufacturer in Japan is waiting on beryllium material. Stay tuned — we’ll update this listing when stock becomes available.

Contact ZSM Custom for pricing and availability.