"I figured I'd better start lookin'." Anderson told SUPER CHEVY. "Everybody else was doing stuff where electronics controlled the valving in a hydraulic shock. They'd never be able to make that fast enough to do what a reactive suspension needed to do. The fastest we'd ever heard of was about 50-millisecond response time. We needed a couple of milliseconds. It was highly unlikely anyone could build something using mechanical servos that could respond that fast.
"When I saw the research being done on MR fluid, I decided we better get involved because that technology could make a shock that could respond quick enough. That led me to Lord. They have done more [with MRF for motion dampers] than the rest of the world put together."
In late 1999, Carrera introduced "MagnaShock 1", an oval-track shock absorber and the first commercially-viable application of MRF to an automotive suspension damper. The system has no computer controls and the shocks are "50/50", offering the same damping authority on both compression and rebound. That authority was varied by a control box that could operate one, two, or four shocks. The adjustment is accomplished by rotary switches. The shocks' range of authority is seven of the damping "units" on the scale that is industry standard in oval track racing. The controller can be programmed to use any five of those seven ranges.
A popular application of MagnaShock 1 in late model oval-track cars is a single pair on the right side. This is a cost effective because shocks on the outside of the turn are the most critical from a chassis set-up perspective. The advantage of MagnaShock is in quick shock-tuning changes, which significantly reduced test time and offered the driver the ability to change the car's chassis tuning during a race.
In late 2002, Carrera introduced a second, more refined and sophisticated "MagnaShock 2," which is adjustable on both compression and rebound. Each shock contains a sensor that sends piston position and velocity data to the MagnaShock 2 controller. With that information, a processor using Carrera's own software algorithms sends a signal to four shock drivers, which command the level of damping the user has selected.
MagnaShock 2 has developed a following in the road racing community because it can be programmed with different damping authority for both compression and rebound. Like MagnaShock 1, the shocks have a damping range of seven. A MagnaShock 2 controller is designed to run four shocks and can store up to five different set-ups each having five steps. A common use of this memory feature is a tiny switch on the steering wheel allowing the driver to select two or three different set-ups during a race or even on a per-lap basis.
"Almost every track has one turn-usually a real sharp one-which the person doing the set-up has to give away," Carrera's Dick Anderson said. "If you set-up to go fast there, you'll be terrible everywhere else. Usually, they give that one up in favor of having a better set-up for the rest of the track. If you were really fast in that turn, too, you could gain a half or even a full second per lap. With MagnaShock 2, you can change all four shocks just for that turn. Flip the switch and you're in that set-up. You'll come off that turn like a rocket."
The MRF Lord makes for Carrera is similar to what Delphi uses in production Corvette shocks. The Carrera hardware is also similar to Delphi's in that both are mono-tube, gas-filled dampers. Materials are where there are some differences. Carrera shock tubes are billet aluminum whereas Delphis are steel. Delphi uses a segmented, annular MRF passage whereas Carrera uses a full annulus. The pistons on both are composed of a magnetic coil and annular passages though which the MRF flows; however the Delpi passage is segmented but the Carrera is continous. Another difference is there is a Carrera piston has only one area where MRF forms fibrous matrices. In a Delphi MagneRide shock piston there are two.