An insde look at the BILSTEIN BLACK HAWK Off-Road Racing Shock

Apr. 01, 2005 By ORC STAFF

An insde look at the
BILSTEIN® BLACK HAWK ™
Off-Road Racing Shock

2005 SCORE Desert Series
Fast Facts:
  • One piece 6061 extruded aluminum body with hard anodized finish
  • Radial Bypass Damping technology
  • IFMV – Incremental Flow Metering Valve with 9 settings
  • 30% faster heat dissipation
  • Up to 100° cooler peak operating temperature
  • 10% - 25% lighter than similar welded bypass steel shocks
  • 1-1/8” hard chromium plated piston rod
  • 3” hard anodized piston with high flow ports
  • Massive 4-1/2” x 12” 6061-T6 aluminum reservoir housing with anti-cavitation valve ( ACV )

Serious off-road competitors now have a dynamic new shock to consider – the Bilstein Black Hawk™ 9300 Series racing shock. The Bilstein Black Hawk™ isn’t just a revision of an existing product, but is an all new shock packed with technological advances. The only thing that can rival its revolutionary performance is its radically innovative design.

Visually Impressive – Extensive Engineering

Bilstein engineered this shock to outperform all others on the market, while incorporating a dramatic and distinctive appearance. Each Black Hawk™ is manufactured using extruded 6061-T6 aluminum alloy, resulting in an incredible 25% reduction in weight. The three-inch inside diameter body is precision bored, then carefully honed to finite tolerances. This precision bore results in longer piston band life, reduced frictional resistance, and ultimately, less heat generation.

A major benefit to this extruded design is the use of integral bypass features. The Black Hawk™ bypass ports are gun-drilled to length. Custom tooling is used to drill the port linking the bypass port and the main body. By allowing the port to be drilled from the inside, the need for external plugs is not necessary, removing in the potential for seal failures. The extruded design eliminates the welding process which can cause distortion to the internal bore.

A significant difference over other shocks is Bilstein’s Patent Pending Incremental Flow Metering Valve (IFMV) in the bypass ports. Most shocks use a cone, or bullet style, check valve piston adjusted by a threaded stop pin. The amount of flow is governed by the position of the cone check valve in the bypass tube resulting in an inaccurate bell curve flow rate between adjustment settings. In contrast, Bilstein’s patented IFMV piston operates by opening only as far as necessary for the pressurized oil to freely flow by. This setup allows for a more linear and specific rate of oil flow resulting in better control over the function of the bypass tubes.

The adjusters for the bypass valves were engineered with ease of adjustment in mind. A 3/8-inch socket or wrench is all that is necessary to adjust them, simplifying the process versus previous, more cumbersome designs. A spring-loaded detent ball produces an audible and positive click through nine positions of adjustability. Adjusters are color coded for quick identification: blue for compression, red for rebound.

The unique working piston of the Bilstein Black Hawk™ is also made from 6061-T6 aluminum and hard anodized. The three inch O.D. piston uses a one inch wide wear band to increase lateral support and to provide complete coverage of the bypass ports in the main cylinder. Angular ports are positioned to support the valving shims throughout the circumference, improving flow and reducing valving fatigue.

The massive cooling fins of this shock are another distinctive feature of the Bilstein Black Hawk™. Offering much better heat transfer than steel, the aluminum fins are an integral part of making the extruded shock body one huge heat sink. Air flow over the shock cools both the body and the fluid inside. Bilstein testing has demonstrated that this design lowers peak operating temperatures by as much as 100° F.

The rod-end assemblies are also crafted out of solid aluminum and are available in a variety of offsets to accommodate different mounting configurations. Inside the aluminum rod-end is a ¾-inch ID Teflon-lined spherical bearing. Optional 1/2 inch or 5/8 inch diameter bearing spacers are available. The 1-1/8 inch piston rod is precision ground, polished and then Hard Chromium plated. This surface finish allows oil to accumulate on the shaft as it cycles to help lubricate the seals.

The end cap of the shock uses the same spherical bearings found at the bottom of the shock. Bilstein developed proprietary bearing cup seals to keep dirt and water from entering the bearing assembly, substantially lengthening service life.

At an impressive 4-1/2 inches in diameter, the remote reservoir is significantly larger than anything else currently available. It’s inside this reservoir where Bilstein really stepped up the design, providing a major advancement in shock absorber technology with the Anti-Cavitation Valve ( ACV ). This valve reduces the amount of gas pressure required in the shock by 83%. Working much like the piston in the shock body by using valve shims to govern oil flow, the Anti-Cavitation Valve also maintains positive gas pressure in the shock. Gas pressures are reduced from an average of 250psi to a minimum of 50psi, virtually eliminating the “gas spring” effect found in other designs and giving the vehicle greater damping control and improved driver feel.

With all of its technological advancements, the Bilstein Black Hawk™ Radial Bypass Damper gives off-road racers a revolutionary new choice to equip their vehicles for victory.


SHOCK BODY

• Rapid heat dissipating, one piece extruded 6061 aluminum construction featuring Radial Bypass Damping (RBD) technology

• Approximately 30% faster cooling efficiency than steel and up to 100° lower peak operating temperatures

• Stronger and 10%-25% lighter than similar welded steel bypass shock bodies without the distortion from welding

INCREMENTAL BYPASS FLOW METERING VALVE (IFMV)

• Extremely accurate, incremental flow adjustment within a sealed mechanism for extreme resistance to dirt contamination

• Easily adjustable color-coded Rebound (red) and Bump (blue) bypass adjusters with an internal detent feature providing prominent "clicks" to each of the 9 settings

• High impact, copolymer check valve piston providing excellent wear characteristics

SHOCK PISTON & ROD

• 3" O.D. 6061-T6 aluminum, Type III hard anodized piston with high-flow ports and 1" tall low friction bronze backed wear band with O-ring seal

• Industry’s largest Hard-Chromium plated piston rod currently offered at 1-1/8" O.D.  

REMOTE RESERVOIR

• Massive 4-1/2” x 12” 6061-T6 aluminum reservoir housing

• Anti-cavitation valve ( ACV ) and larger reservoir diameter reduces the required gas pressure (130%-175%), lowering the piston rod pressure and giving the vehicle greater damping control

Coverage brought to you by Bilstein

Race@Off-Road.com

 www.Off-Road.com


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