Suspension

There is not that much to show of the build at the moment as we are waiting for a few things from other sources and the engine is being rebuilt. It will all be coming together this week, so should be a lot going on by the end of the week. Will we make the event on the 13th? Well we are not so sure anymore, time is ticking.

We put some adjustable platforms in the rear by simply added threaded tube to the top of the diff where the standard platforms where. This is a much simpler and more cost effective way to add adjustability instead of making coil-overs. We have always had problems finding springs that will fit the rear. On gravel we use standard springs that have been compressed to get the ride height down. On tarmac we have been using King Springs KFFL-11 which are a low front spring from an Escort but they fit perfectly and give a good ride height but they have always been slightly to soft. So what are the options, well not many because you cant search for standard springs by size and then if you do find one you have no idea what the spring rate is. So the only option was to go to a race spring, all 65mm and come in all sorts of sizes and spring rates. So that should have made finding springs easy right? Well it would seem not.

We put the springs we had into a suspension dyno to find out what the actual spring rates are. The result are a surprising low, a standard spring is a linear 65lb/in (I know we live in a metric world, but somethings remain in the past) the KFFL-11 is slightly progressive and about 100lb/in and a 175lb spring is not surprisingly 175lb/in. Now based on the KFFL-11 ride height we calculated we would need a 7 inch tall spring and a spring rate of just over 100lb/in. Trying to find those took up half a day only to find no one makes springs that soft until they get to about 10 inches tall. Tein are close with a 8 inch with 112lb, but King Springs, Eibach, H & R etc, not even close. We have found that offroaders and ATV’s use something that could work, but more research will need to be done.

We have also been playing with the brakes. In order to keep things simple (a bit ironic considering the work that is going into the engine) we have always used overpowered rear brakes and controlled them with a proportioning valve. Last year we put 300ZX brakes on the rear, but the pedal has never been quite right and is a bit inconsistent. So we have decide to try it with the brake booster removed. It will be like standing on a brick, but hopefully a consistent brick. We also remade the brake lines as the original one are in the way in the engine bay.