Underdrive Crank Pulleys for LS, Coyote, K20, 5.7 Hemi, 2JZ, RB, EJ

What Crank and Underdrive Pulleys Cover

Reduced accessory drag

Underdrive crank pulleys reduce accessory speed relative to engine speed. The result can be less parasitic drag at higher rpm when the rest of the accessory drive is correctly matched.

Crank Pulleys and Engine Dampers

Balance and timing matter

A crank pulley can be separate from a harmonic damper or integrated with one. Confirm the engine balance requirement, trigger wheel arrangement, belt alignment, and damper design before choosing a part.

Accessory and Idler Pulleys

Keep belt tracking stable

Idler, alternator, and water pump pulleys guide the belt and establish accessory speed. Replace worn bearings and inspect pulley grooves when servicing a noisy or slipping drive system.

Supercharger Pulleys

Match boost goals to the tune

Smaller supercharger pulleys can increase blower speed and boost. Fueling, charge-air temperature, belt grip, and calibration must support the intended pulley ratio.

Vehicle Fitment and Belt Drive Planning

Build the whole system

Honda and Acura K-series and B-series builds, Subaru EJ and FA platforms, Ford Mustangs, Mini R53 models, Mazda rotary cars, and Mitsubishi 4G63 applications use different belt layouts and hardware.

Top Pulleys - Crank, Underdrive Brands

• ATI. Harmonic dampers and race-focused crankshaft control hardware.
• Fluidampr. Viscous crank dampers for high-performance engine combinations.
• Gates. DriveAlign idler and accessory drive replacement components.
• PERRIN. Lightweight crank pulleys for Subaru performance applications.
• Torque Solution. Accessory pulleys and drivetrain upgrades for sport compact builds.
• Weapon R. Engine dampers and tuning-focused hardware for Honda and Acura.
• GReddy. Performance pulley kits and Japanese sport compact components.
• ALTA. Mini Cooper supercharger and crank pulley upgrades.
• Innovators West. SFI-rated dampers and accessory drive systems.
• March Performance. Serpentine accessory drive solutions for domestic engines.
• Mishimoto. Cooling and engine bay hardware for performance vehicles.
• Skunk2. Honda and Acura performance engine components.
• AEM. Engine management and supporting performance hardware.
• HKS. Turbo and sport compact performance parts.
• Blox Racing. Honda-focused engine and chassis components.

How to Choose the Correct Crank or Underdrive Pulley

• Confirm the exact engine code and vehicle year before ordering.
• Match the pulley to the original belt path and rib count.
• Verify crank balance and harmonic damper requirements.
• Measure belt alignment after any pulley or bracket change.
• Check accessory speed when selecting an underdrive ratio.
• Use a compatible belt length after changing pulley diameter.
• Confirm supercharger pulley bore, hub, and belt style.
• Inspect idler bearings and tensioner condition during service.
• Plan tuning and fueling changes for increased boost.
• Review local rules for modified engine and emissions equipment.

Common Questions

How do I confirm fitment before ordering?

Use the year, make, model, trim, engine, and drivetrain filters on the product page. Review the application notes before ordering, especially on modified vehicles.

Do I need other parts for installation?

Some installs need hardware, wiring, gaskets, or supporting components. Read the product details and installation instructions before beginning the job.

Are these parts intended for daily driven vehicles?

Many parts are built for street vehicles, but the right choice depends on the vehicle, tuning level, and local regulations. Check each product page for use notes.

Can I install this at home?

Many bolt-on parts are suitable for experienced DIY installers. Use the correct tools and follow the manufacturer instructions. Complex engine work is best handled by a qualified shop.

What information should I have ready for support?

Have your vehicle year, make, model, trim, engine, drivetrain, and the product part number ready. Those details help confirm the correct application.

Do products include a manufacturer warranty?

Manufacturer warranty coverage varies by product and brand. Review the warranty details on the product page and retain your proof of purchase.

How quickly do orders ship?

Most in-stock orders ship promptly from a US warehouse. Delivery time depends on the part, warehouse location, and shipping destination.

Can I return an unused part?

Unused parts in original packaging may be eligible for return under the store return policy. Special-order, installed, and modified items can have different eligibility.

Will a modified vehicle need additional setup?

Changing crank or blower pulley ratio can require belt length changes, belt alignment checks, and an updated calibration. Confirm supporting components before increasing boost or rpm.

Can Black Ops Auto Works help select the right part?

Yes. Contact the team with your vehicle details and build goals for help narrowing the compatible options in this collection.

Why Buy Pulleys - Crank, Underdrive from Black Ops Auto Works

Black Ops Auto Works stocks 89 Pulleys - Crank, Underdrive SKUs with real fitment data, competitive pricing, and support from staff who build these vehicles themselves. Products are filterable by year, make, model, trim, engine, and drivetrain to confirm the correct application before ordering.

For focused shopping, browse our Pulleys, Crankshaft Dampers, Supercharger Pulleys, ATI, Fluidampr, Air Intake Systems.