i have a pretty smart chassis man that has built/dynoed his share of shocks. He steered me clear of the double adjustable shocks..i ask him why?..he advised me that there was NO WAY that the bleed over from the compression and rebound could be seperated in one canister as the double adjustable shock is designed....although the claims are made that it can be done by the manufactures, he advises that unless there is a independant canister there is no way both compression and rebound can be accuratley (seperated) attained from one cylinder....i went to the BIG BOYS (NHRA SOUTHERN NATIONALS) race last week and looked under several of the BIG name cars such as Greg Anderson etc...low and behold i saw double adjustable shocks but with a independant canister with remote wiring (NONE of the Double adjustable stuff being sold as we know it)....i do not know what brand they use cause i could not get close enough..( i assume they have them custom built or something to that degree) but i will list a few brand name manufactures that build these shocks..they are the TRUE double adjustable shocks and they are very HIGH PRICE...
Now i AM NOT trying to steer anyone away from buying a double adjustable shock..its your money do with it as you will..i just wanted to give you the side of a true double adjustable shock that the manuafactures will not tell you...I personally have single adjustable shocks and will not touch the SO-CALLED double adjusteble shock for the reason i am stating in this thread..its a waste in my opinion. here are a few brand names and a little literature from one of the sites..PLEASE DO YOUR OWN RESEARCH BEFORE YOU GO PAYING FOR A DOUBLE ADJUSTABLE SHOCK..."Get what you pay for" AND BE YOUR OWN JUDGE !!!!!!.......
( THE ABOVE IS MY OPINION ONLY. IT IS NOT INTENDED FOR NOTHING MORE THAN A PERSONAL OPINION !!! )
#1- OHLINS #2 BILLSTEIN #3 PENSKE....
below is some info from the OHLINS site on the introduction of this shock.
The TTX damper is the culmination of three decades of Ă–hlinsâ€™ successful participation in world championship events winning more than 100 World Championships. Many years of work together with some of the worldâ€™s most successful racing teams together with advanced dynamic analysis methods developed at Ă–hlins Racing headquarter in Sweden has given Ă–hlins the unique knowledge needed to design the TTX damper.
The Ă–hlins TTX damper, originally developed for formula racing, is designed to handle the demanding damping characteristics needed for all types of tracks, from street courses to super speedways
The TTX damper is fully adjustable with maximised damper response together with qualities youâ€™ve never seen before when it comes to "settings".
Low and high speed compression and rebound damping are externally adjustable and fully independent. The adjustment range is huge with equal increments of force throughout the adjustment range. Even the shape of the damping curve can easily be changed. All adjusters affect the flow from the main piston, not the piston rod displacement volume.
Some classes may need the TTX 40 with 3 or even 2 adjusters. For this puropse there is a needle housing that uses the existing parts in the 2-way adjuster and transforms it to be a 1-way adjuster suitable on either compression or rebound or both. Part number for this needle housing is 05953-03. Preload changes is made by adding shims on one or boths sides of the coil spring. Shims that should be used in the 1-way adjuster are: 00610-16, 00615-16,00625-16 and 00630-16.
The compression damping forces of the TTX damper are not, as in a conventional damper, caused by a pressure drop on the rebound side, but by increased pressure on the compression side. This reduces the risk of cavitation and makes any reservoir valve or high gas pressure unnecessary. So, no balancing of reservoir damping to main piston damping is needed to avoid cavitation and improve damping response. Maximum response and minimum risk of cavitation will always occur. With no reservoir valve, the internal pressure of the damper unit will be kept to a minimum. The low amount of hysteresis results in excellent short stroke/high force performance. Also, a very low gas pressure can be used without any loss of damping performance.
Along with the damper comes a unique Valving Reference Program (available for download free of charge at http://www.ohlins.com/Automotive/Pro...rmulaSportscar). This computer model of the damper will allow you to find damping curves without a dynamometer. It will reduce building time tremendously and allow exact damper adjustments in pit lane. The TTX product will revolutionise the work for mechanics and engineers in the racing business.
This manual text is based on TTX dampers starting with Ă–hlins part number TTX NE0. These are through rod type dampers loaded with several new concepts. As always, all dampers are tested before they are delivered to the customer. In keeping with Ă–hlins long tradition of perfection, quality is outstanding and long life is to be expected.
Welcome to the World of Ă–hlins.
After the Ă–hlins TT44 was introduced to the market in 1996, it very quickly became one of the most popular dampers in formula racing. For some period, more than 95% of the cars in The Champ Car World Series were using TT44 dampers.
There are several reasons why the TT44 became so popular. One reason is that it came with some new features not available on other dampers. One of them is the powerful low speed adjusters, totally independent and with the compression adjuster restricting the oil flow from the main piston, not only from the piston rod displacement. Another is the compression high speed adjuster, giving new possibilities to reshape the compression curve.
When designing the new TTX, the goal was to come up with a damper which would be just as big a step forward as the TT44 had been. Highest priority should be not only to design a damper with excellent performance, but also a damper easier to work on and use than any other product available.
During the development several patent applications were made.
Six of the most important design criteria for the TTX are listed below.
1. No reservoir valve
The damper design should be with no reservoir valve. In dampers where reservoir valves have to be used to avoid cavitation, one more parameter has to be optimised â€“ the right amount of reservoir damping.
The hysteresis will be minimised, as no reservoir valve has to be used. All damping comes from the pressure drop over the main piston. Damping forces from a reservoir valve always causes more delay in the damping force build up. See chapter Hysteresis for more information.
Using reservoir valves always increases the internal pressure. The friction from the piston rod seal/seals can be kept low because of the low internal pressures.
2. Main piston flow
Another criterion was to have all the adjusters regulate the flow from the main piston. This will give the maximum pressure area and because of this, the maximum oil volume to regulate.
The larger the pressure area is, the lower the internal pressure will be for a given damping force. The lower the internal pressure, the less flex there will be. The flex is caused by expansion/compression of the damper body and compression/expansion of the oil. The result is excellent short stroke/high force performance.
With a large volume of oil passing through the valves , it becomes easier to control the restriction of the oil. In other words, the matching of dampers will be improved.
3. Full adjustability
On the TT44/TT40, it was never possible to use a high speed rebound adjuster in combination with a high speed compression adjuster. On the TTX, we wanted to be able to combine those two while keeping them completely independent from each other, as with the low speed compression and rebound adjusters.
Poppet valves preloaded by coil springs were picked to become the high speed valves, as they can be made very compact in size and precise in opening pressure. This type of valve very often gives an abrupt opening characteristic, resulting in a sharp "knee" in the damping curve. To make the "knee" more rounded and to be able to change its shape, some shims are added to the face of the poppet valves. By changing these shims, the shape of the "knee" can be affected.
4. Simple valve changing
Even if the adjustment range of the external adjusters is huge, sometimes there might still be a need to change the valving of the dampers. In other words, change one or several of the following parts: poppet valve/valve seat, coil springs and nose shims. As this very often is done at the track and has to be done quickly, this job has to be simplified as much as possible. Compared to reshimming a conventional damper, any of the changes in the TTX will be a lot quicker. The result exceeded our demands.
Also it should be possible to fill the damper without a vacuum-filling machine, as this otherwise would be a limiting factor.
5. Through rod damper
A through rod damper has some technical benefits. One is packaging, which is a main issue on formula cars. The reservoir volume can be very small, as there is no piston rod displacement. Here no external reservoir is needed. Also there is no gas force pushing the piston rod out of the damper body. (The word "nose pressure" is sometimes used for this force.) Here the nose pressure is zero. This has several advantages. The nose pressure doesnâ€™t vary due to temperature changes and you donâ€™t have to fight the gas force when installing the damper on the car or in the dynamometer.
Designing a through rod damper gives the possibility to separate the rod bushings and keeps the distance between them constant. If coilover springs are used, the amount of friction will be tremendously reduced.
As the piston area for compression and rebound are identical, the damping forces will be the same if the same valving is used and the adjusters are set the same. To some degree, this simplifies the use of the damper.
For all the above reasons, race teams have been interested in through rod dampers. Also, when introducing the TTX, we wanted it to be something very different from the other products out on the market.
6. External clocking
Another strong side of the TT44/TT40 was the possibility to clock the reservoir bracket at any angle. This function we wanted to keep on the TTX damper, to ensure an optimum installation on any car. Just as on the TT44/TT40, the clocking of the adjusters on the TTX in relation to the top eye should be possible to change without opening the damper.