1999-04 Cobra, Bilstein HD series damper package for IRS-equipped Mustang, includes 2 Bilstein HD struts and 2 Bilstein HD shocks, with integral progressive bumpstops.
Struts are suitable for both stock-location springs and coil-over conversions. See chart below for spring recommendations.
Rear shocks may be modified for acoil-over conversionby machining a groove in the shock body. Order package numberBIL-9.1(with its pre-grooved shocks) if a future rear coil-over conversion is a possibility.
For more details and technical information, scroll down.
Heavy Duty (HD) BilsteinSpring Recommendations
Conventional Spring Sets
MM Road & Track H&R Race H&R Super Sport H&R Sport Eibach Pro-Kit Stock Springs
Coil-Over Spring Rates
250 - 325 lb/in
IRS Rear Springs
475 - 525 lb/in
Firm, yetgood ride quality, as is expected of a performance car
Bilstein struts and shocks are made with patentedmono-tubetechnology
Invertedstrut design has very large strut shaft bushings for greater resistance to deflection from cornering loads, and protection of the oil seal
High nitrogen gas pressureprevents oil foamingand resultantfading
Monotube design has betterheat dissipationthan twin-tube dampers, keeps the oil cooler, and decreases heat-induced damper fade
Velocity-sensitive valving improves ride quality
Each Bilstein strut and shock istestedon a shock dyno
The Bilstein rear IRS shocks in this package may be grooved for coil-over conversions, and come with an integral, progressivebump stop
Bilstein struts and shocks includedustcovers
MM Sport series and MM Race series dampers are better suited for moreaggressivespring rates.
Tech Heavy Duty (HD) Bilsteins work very well in street applications with a variety of both conventional springs and coil-over conversions. They are designed to deliver the best possible ride quality coupled with impressive street performance. The HD series dampers were not designed for use with overly aggressive spring rates, particularly in coil-over conversions. For dampers more suited to aggressive spring rates, see the MM Sport series and MM Race series dampers.
While they are non-adjustable, Bilstein's unique deflective-disc valve design instantaneously self-adjusts to changing road surfaces. Their performance does not degrade with age, usage, or heat, requiring no compensating manual adjustments as with other brands. Bilstein uses a patented mono-tube design that allows for a larger piston size than is possible with a twin-tube damper. The mono-tube design provides better heat dissipation to keep the damper's oil cooler, and decreases heat-induced damper fade. High-pressure nitrogen gas prevents oil foaming and fading. The unique inverted design of the Bilstein strut allows for very large strut shaft bushings, which are less prone to deflection. The inverted strut design also keeps the oil seal protected from the elements. Every Bilstein damper is tested on a shock dyno before leaving the factory to ensure quality.