HP Autowerks, Inc. is proud to announce the new AST 4250 Series Damper. The new design builds on the success with the AST 4200 series damper and the recent wins in GRAND-AM Continental Tire Sports Car Challenge, including new technology developed specifically for GRAND-AM racing teams.
New for 2012 AST 4250s with digressive valving and several other advantages over previous models. Shopping for a quality set of coilovers for your BMW 1M or M3 can be a little overwhelming. Many people turn to the forums to make a decision. The problem with this is anyone can post anything on forums. The information you get will likely be out of date and many people who recommend a coilover on forums do not have any direct experience with anything other than the coilover the are recommending and their oem shocks. If you look past all of the re-branding and forum hype you can make an informed decision.
Before you spend over $2500 on coilovers it's important to understand what you are buying. To know that you are getting the best possible set up for your application and budget you must understand the differences between the options you are considering. We strongly believe that in this price range AST 4250s are by far the best option. These are Dutch made monotube coilovers with digressive valving. All other options in this price range (including KW Clubsport and Competition 2-way models) are twintube inserts, out of date linear valving or built in China/Taiwan. Monotube coilovers are superior to twintube coilovers in all aspects of performance. They provide a larger range of adjustment, respond quicker and deal with heat/heavy use better. Digressive valving is better than linear valving in all aspects of performance because it allows damper manufacturers to properly set up both low speed and high speed damping instead of having to compromise between the two. This means you get the best of both worlds. Instead of a damper that only handles high speed or low speed damping correctly, you get a damper that handles both of them correctly at the same time! These will give you better lap times than other options in this price range and give you better ride quality on the street as well.
DDP Technology Piston
Our latest digressive piston developed for GRAND-AM gives drivers and race engineers the best of both worlds. Drivers love the low speed damping response and body control, while race engineers love the “blow off” at high shaft velocities. When the rebound adjustment is soft, the damper curve looks similar to an OEM street shock profile. When the rebound adjustment is hard, the damper curve looks like a race shock!
This “Jekyll and Hyde” personality is exactly what AST 4000 Series customers want: soft street ride and race car track performance in ONE shock - all with the turn of a knob!
Lower Drag Seals
High performance seals are a challenge for any damper. They must balance friction and sealing ability while not impacting shock performance and not leaking; a difficult balancing act! While the seal was originally developed for GRAND-AM road racing, AST is taking our knowledge from the track to the street again. Newly redesigned seals decrease hysteresis in the damper and decrease seal drag over 50%.
Discontinuing Steel Shocks
In 2012, most AST 4250s will come with aluminum shock bodies. Strut bodies will continue to be built from steel, but all shocks will switch to aircraft grade aluminum. Economies of scale have allowed us to switch to aluminum without a large increase in cost of manufacture. For some models, this represents a 50% reduction in the weight of the damper (unsprung weight).
Structural Improvements
Several new designs proven in GRAND-AM racing will be added to various products on an “as needed” basis. All strut models will receive a new two piece top guide assembly that separates the dust seal assembly from the oil seal/bearing assembly. This two piece design is stronger in compression loading (bottoming out) and side loading (in the turn). Some models will receive weld-on stabilizer brackets which take the guesswork out of setting the stabilizer height and torque setting of the clamping ring.
Upgradeability
4200s will be upgradeable to 4250s! 4200s customer can upgrade to the new internals very soon! An upgrade matrix will be published in mid 2012.
For more information:
http://www.m3post.com/forums/showthread.php?t=656598