Shock Valve Options:
How to understand the valving on a BSB 12 and 13 Series shocks. First, we look at the 4 different call outs and break them down.
30/30: Rebound/ Compression and this is the same as a 3-3. When looking at a standard scale used by Bilstein back in the day a 30 valve was 160 pounds of pressure at 10 inch per second of speed at the shock. That means the shaft was moving 10 ips and making a force of 160 ponds. Unlike other companies Bilstein did the same thing on both side of the shock, meaning that a 30/30 would make 160/160 pound of force. When we build a shock like this (30/30) we do it with a 4-bleed full bleed shim on both side and allow for 20 pound of tolerance at 10 ips.
160/160: Still Rebound/Compression and still a 30/30 but on a tighter tolerance, this with just 10 pounds of tolerance. This shock is still built on a 4-bleed full system and has a minimally value at low speed.
RF1-50/130: This is where we start building low speed car control in the shock. Frist is the location call out like the RF or LF followed by the 1 which indicates that the low speed has been modified (bleed system). The 50 is the 1-inch number in pounds when dynoing the shock at 10 ips. As this number increases the low and high speed rebound also increase, the high speed at this point is there to build strength for the low speed and is not as important so it is not added to the call out. The (/) forward slash separates the rebound from compression and the 130 is the high speed compression number. Depending on how the shock is built will depend on how we look at the compression number on the dyno. This shock is built on a smaller bleed system than the first 2 shock and also on a ring shim which adds preload to the shim stack increasing the power of the stack. Valving a shock this way will allow a ton of room to work in the valving range and could provide all the builds necessary to build a small body shock. Range runs from 30 to 100 which is a very good range to work in while allowing the shock to have bleed which will allow grip. Bleed in the shock is decreases as the number goes higher but still allows for spring return in the car.
RFGF-300/130: This is a low bleed shock system that crates zero point in the shock which makes holding power or rebound. The RFGF indicates the location and the fact it is a zero-point shock. The 300 is the amount of zero point in which the shock has and as that number increases the holding power of the shock increase. This shock can range from 200-800 zero and is built on a small bleed system intended to make larger low speed numbers which will turn the car well. This shock is built on a constant shim stack and bleed system with preload being the changing factor in the shock. The (/) forward slash separates rebound and compression and the 130 is the compression. We can vary the amount of compression to act with the car and what is happening to it for the conditions. This is a very big shock for this car with a lot of tie down it is going to turn it hard all day long, so if you are even thinking drive don’t go this route.