28 SERIES INTRODUCTION
The 28 Series is a line of mono-tube shocks and struts specifically designed for competition purposes, featuring individual external adjustments for compression and rebound forces. The 28 Series earned an impressive worldwide resume raging from premier series like Formula 1, Champ Car, Indy Racing League, Formula 3, the Grand-Am Koni Challenge series, British and German Touring Cars, etc. down to amateur championships including the SCCA and NASA.
The 28 Series has garnered victories at the world’s most prestigious races including the Indy 500, LeMans 24 hr and others. The 28 Series is the shock of choice of racing manufacturers including Dallara, and leading teams including Pro-Drive.
The 28 Series uses an advanced adjustment cartridge that controls the opening and closing of valve loaded ports. Distinct stops (clicks) assure that each port can only be either open or closed. Thus total repeatability of performance is engineered into the damper.
WORKING PRINICIPLES OF 2817
The 2817 is an inverted mono-tube strut that has been designed to handle the special loadings for a strut style suspension.
The 28-Series Race Shocks are mono-tube dampers, meaning the damper has only one working tube. When the piston rod is pushed into the body of the damper, it displaces its own volume in oil. To make this possible a part of the Damper is filled with nitrogen and separated from the oil by a floating piston. When the piston rod is pushed into the body of the damper, its volume will push down the floating piston a small amount and thereby create more space in the cylinder to accept the incoming piston rod. With movement of the damper, oil will flow through separate cartridges located in the piston. In these cartridges the oil will flow through valve loaded ports. When the oil flows through it creates a pressure drop over the piston which give a damping force on the piston rod.
Two cartridges are contained in the main piston, one for bump and one for rebound. They operate totally independent of each other. For both bump and rebound 8 adjustment positions are available. By having all forces generated by the piston itself, the control over the damping forces is very precise. A separate reservoir is not needed to accommodate the bump adjuster. This makes the installation simple, lightweight and clean.
The 2817 series trut uses a ‘twin guide’ installation. The primary guide is fitted to the top of the main cylinder. The secondary guide is fitted to the lowest point of the damper body itself and runs up and down inside the strut housing. Therefore as the strut is compressed, the distance between the two guides increases. This reduces friction and increases strength dramatically under load.