A line lock is a device that will allow the user to lock only the front wheels. This is used by people who drag race to stop the car from rolling forward when doing a burn out. It also allows the rear wheels to spin freely since the rear brakes are not engaged.
Most people just power break applying the gas, spinning the tires, and holding the breaks at the same time. This causes the rear brakes to 'glaze' wich will reduce thier performance and life.
A line lock allows you to do the burn out without the negative side effects of powerbreaking.
I have seen a line lock installed on XLER8's black Supra. You can contact him on this board and he should be able to show you some pics of his install and maybe tell you how it was hooked up. I think his car is a 94 or 95.
My car is a 97 and the ABS system is set up quite differently. I have a hurst linelock sitting in my garage waiting to be hooked up. I have yet to find someone who knows how to install the line lock on the ABS setup found on my 97. It can definitely be done on earlier supras.
I have heard from some that they think you have to hook it up after the ABS system. This would most likely force you to use two of them. I am still trying to figure out how to do it with just one line lock. One thing is that I may be able to hook it up before the ABS and then pull the fuse before I use it at the track. Not sure. Anyone who has some ideas on this please email me.
I suggest buying the Hurst brand line lock since it is well built, rebuildable, and looks the trickest.
Pete