Sorry to hear about your troubles with the HKS's. I had the same problem when I used the Tein-supplied bump stops... then I put the stock (untrimmed) bumpstops back on and they were perfect.Magic said:Actually, I have a ton of input on the HKS coilovers. I have them in my car. I have also driven several supras with the Tiens and I have also driven supras equipped with standard Eibach springs.
The construction quality of the HKS coilovers is superior to any I have seen. They are built to take a punding and have an extra valve that you can hook up a remote resivoir to in case you need to increase the shock volume to prevent over heating of the oil in extreme racing situations. The resivoir is overkill and not needed for the street or light track duty so it is only an extra option from HKS japan.
There are three versions of the Hyper dampers that were released in the US. The first and second versions use a progressive rate race spring. The spring rates used are a little less than the Tiens. You can email me for the exact spring rates used in the first and second release of the coilovers. The ride is pretty soft and the dampening has a very wide range of adjustability from very soft to pretty hard for the track. The second version only differs becuase it has an updated shock that has the same specifications except it is 20 way adjustable. Version one is 10 way adjustable.
The third and newest version that was released in the US had enough changes that HKS actually changed the part number. It uses a 30 way adjustable shock and they switched to a stiffer liniear race spring using spring rates that are almost exactly the same as the tiens. The tiens have a helper spring to soften up the ride a little and keep the spring from moving around. It is not required and HKS does not use it.
I have the second generation coilovers mentioned above and am extremely happy with them except one problem....
The front tires bottom out on the top of the inner fender lining in the front. This only happens if I hit a medium sized sharp bump. Just driving down a flat street this does not happen. In my opinion the bump stop used is just too short. This was done by HKS to allow for more travel. More travel is usually a good thing.
This is a problem on the supra because right were it hits the fender lining on the other side toyota decided to put a wiring harness of some kind. Eventually using coilovers with too much travel you will wear through the lining and start to wear through the harness. The harness can not be relocated easily.
In addition with the HKS coilovers you can NOT change the bump stops without dissassembling the ENTIRE shock. That means you would have to rebuild the shock just to replace a simple bump stop. In my opinion that is a very stupid design.
On the other hand, with the Tiens you can simply slip any bump stop over the shock tube that you want simply by taking it off the car.
When replacing the bump stop you have to be careful not to limit travel too much. So I would use a trimmed down version of the stock bump stop.
Because of this i would simply go with the Tiens and spare yourself A LOT of HEADACHE.
My coilovers are actually at HKS right now. At this point they have not found anything wrong with them and have not come up with any other solution to this problem. They said they have never heard of this problem. That is funny because I have heard of it happening with HKS and other coilovers on multiple occasions. There is a person who lives near me that is really unhappy with his HKS coilovers because of this.
I personally drive my car very hard if something is not working correctly I will find it, especially with suspension.
When I get them back I am going to try and come up with a solution that I can live with.
I have a couple of ideas. Otherwise I will just probably sell them and get the Tiens.
Please feel free to email me if you have any questions.
Other than that they work great!!!