Hi-Cap Shock Absorbers

Hi-Cap are the series of high-performance shock absorbers derived directly from C.V.A. (‘Constant Volume Adjustable’). The technical concept for damping is common to both families: these shock absorbers combine the action of the oil in the piston chamber and the spring.

When the shock absorber is compressed due to a bump or jump acting on the suspension (picture left),the mechanical action of the piston compresses oil, which is forced to pass through holes in the yellow piston from the upper to the lower chamber. Oil is an incompressible liquid and this forced passage in a limited space (the holes, which are usually two) transforms the kinetic energy of movement into thermal energy: heating oil. The same situation occurs when the shock absorber extends pushed by the spring to return to its rest position (image right), the mechanical action of the piston compresses oil which is forced to pass through the holes from the lower to the upper chamber. This forced passage in a limited space transforms the kinetic energy of the movement into thermal energy by heating oil.
Transforming kinetic energy into thermal energy allows the oil to dampen the suspension action:
– in rebound due to a bump, a jump, uneven ground, etc.
– in extension due to the spring
Physically dissipating energy prevents annoying suspension rebound. To adjust the action of these shock absorbers you can
– change the oil inside using oils of different viscosities and/or
– change the ‘hardness’ of the springs by inserting spacers or changing the springs themselvesthe mechanical action of the piston compresses oil, which is forced to pass through holes in the yellow piston from the upper to the lower chamber.

These are the steps for the correct construction of the Hi-cap shock absorber, if carried out incorrectly they can impair correct functioning:

1- On the metal piston rod (highlighted in blue) install the two C-rings (highlighted in red) and the plastic piston head, which has two holes (highlighted in orange). The holes are used to pass oil from the upper chamber to the lower chamber when the shock is compressed and vice versa. As the number of holes in the disc increases, the oil action decreases and the shock absorber becomes soft. The viscosity of the oil determines its action on the movement of the piston in the chamber. 
2- Insert the newly assembled piston into the cylindrical body of the shock absorber (highlighted in green) together with the BT9 spacers (highlighted in red), the spacer changes its length to increase or reduce the shock absorber stroke,
3- The most complex operation to perform is to fill the shock absorber chamber with oil (highlighted in purple), if you leave air bubbles (highlighted in white) inside the chamber the hydraulic reaction due to the oil will not be predictable and constant. Air is compressible and therefore changes the reaction of the fluid formed by a mixture of air and oil, which is incompressible. Two technical precautions must be taken to avoid having air bubbles. First of all, abound with oil and do not follow the instructions completely; avoid cleaning the shock absorber with a cloth (highlighted in blue) before applying the cap (highlighted in red) and screwing cap SA2 onto the shock absorber body. The second suggestion is to fill the shock absorber with oil, leaving the piston at a height of 1/3…1/4 of the cylinder to prevent an air pocket from stopping at the bottom. If this method is applied, make sure that the lower chamber does not contain bubbles: fill the cylinder halfway with oil, wait until the bubbles all come to the surface, facilitate the passage of the bubbles from the lower to the upper chamber by tilting the cylinder slightly. The two techniques can be combined.

4- insert the spring and screw in the lower eyelet. Springs can be of various types depending on the model on which the shock absorber is installed.
5- select and install C-shaped plastic insert, which has the task of stiffening the spring. The higher the insert, the stiffer the spring becomes

Within the same family it is possible to change the length of the shock absorber by changing the rubber spacer highlighted in red in step 2 and the spring; here are some tables showing how the shock absorbers can be adapted to various lengths.

In some models, Hi-Cap shock absorbers are already provided by the factory:

– Avante model 58072: double front shock absorber in Mini version with piston for 64 mm length; double rear shock absorber in Short version with piston for 82 mm length
– Egress model 58079; double front shock absorber in Mini version with piston for 64 mm length; double rear shock absorber in Short version with piston for 82 mm length

In the other models it is possible to install Hi-Cap shock absorbers as an accessory; list relating the various Hi-Cap shock absorbers to models:
– The Fox model 58051: single front shock absorber in the Short version with piston for 82 mm length ; double rear shock absorber in the Short version with piston for 92 mm length 
– Ford F150 Ranger BlackFoot model 58058: double front shock absorber in Short version with piston for 82 mm length ; double rear shock absorber in Short version with piston for 82 mm length
– Monster Beetle model 58060: double front shock absorber in Short version with piston for 82 mm length; double rear shock absorber in Short version with piston for 82 mm length 
– Hot Shot II model 58062: single front shock absorber in the Short version with piston for 82 mm length; double rear shock absorber in the Short version with piston for 92 mm length
– Super Sabre model 58066: single front shock absorber in the Short version with piston for 82 mm length; double rear shock absorber in the Short version with piston for 92 mm length
– Thunder Shot model 58067: single front shock absorber in the Short version with piston for 92 mm length; double rear shock absorber in the Short version with piston for 92 mm length
– Sonic model 58071: double front shock absorber in the Mini version with piston for 64 mm length; double rear shock absorber in the Short version with piston for 82 mm length
– Thunder Dragon model 58073: single front shock absorber in the Short version with piston for 92 mm length; double rear shock absorber in the Short version with piston for 92 mm length
– Terra Scorcher model 58075: double front shock absorber in the Mini version with piston for 71 mm length; double rear shock absorber in the Short version with piston for 92 mm length
– Vanquish model 58076: double front shock absorber in Mini version with piston for 64 mm length; double rear shock absorber in Short version with piston for 82 mm length
– Fire Dragon model 58078: double front shock absorber in Mini version with piston for 64 mm length; double rear shock absorber in Short version with piston for 82 mm length
– Mud Blaster model 58077: double front shock absorber in the Short version with piston for 82 mm length; double rear shock absorber in the Short version with piston for 82 mm length
– Astute model 58080: double front shock absorber in Mini version with piston for 71 mm length; double rear shock absorber in Short version with piston for 92 mm length
– Nissan King Cab model 58081: double front shock absorber in Short version with piston for 92 mm length; double rear shock absorber in Short version with piston for 92 mm length
– Mad Cup model 58082: double front shock absorber in Mini version with piston for 64 mm length; double rear shock absorber in Short version with piston for 82 mm length
– Ferrari F189 Last Version model 58084: single rear shock absorber in Mini version with piston for 64 mm length
– Avante 2021 model 58085: double front shock absorber in Mini version with piston for 64 mm length; double rear shock absorber in Short version with piston for 82 mm length
– Toyota Hi-lux Monster Racer model 58086: double front shock absorber in Short version with piston for 92 mm length; double rear shock absorber in Short version with piston for 92 mm length
-Manta Ray model 58087: double front shock absorber in the Short version with piston for 82 mm length; double rear shock absorber in the Short version with piston for 92 mm length
– Tyrrell 019 Ford model 58090: single rear shock absorber in Mini version with piston for 64 mm length
– Bear Hawk model 58093: double front shock absorber in the Short version with piston for 92 mm length; double rear shock absorber in the Short version with piston for 92 mm length
– Lotus 102B Jubb model 58095: single rear shock absorber in Mini version with piston for 64 mm length
– Super Astute model 58097: double front shock absorber in Mini version with piston for 71 mm length; double rear shock absorber in Short version with piston for 92 mm length
– Top Force model 58100: double front shock absorber in the Short version with piston for 82 mm length; double rear shock absorber in the Short version with piston for 92 mm length
– Bush Devil model 58101: double front shock absorber in the Short version with piston for 92 mm length; double rear shock absorber in the Short version with piston for 92 mm length
– Jordan 191 model 58103: single rear shock absorber in Mini version with piston for 64 mm length
– Mc Laren MP4/6 model 58104: single rear shock absorber in Mini version with piston for 64 mm length
– Williams FW14 model 58105: single rear shock absorber in the Mini version with piston for 64 mm length
– Studium Blitzer model 58106: double front shock absorber in the Mini version with piston for 71 mm length; double rear shock absorber in the Short version with piston for 92 mm length
-Top Force Evolution model 58107: double front shock absorber in the Short version with piston for 82 mm length; double rear shock absorber in the Short version with piston for 92 mm length

It is possible to change the seal set consisting of o-ring and nylon collar using part 53077.

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