metroracerjim Posted May 12, 2010 Author Report Share Posted May 12, 2010 Some work and research to do then, is there a race grade of hydrolastic fluid because i think it's getting mighty hot. I've not heard of anything. I've never measured the temperature of the spheres after racing, I've never heard anyone mention it. I'll have to have a feel next time I'm out. One of the drawbacks of the suspension is the variability with the ambient temperature. Summer to winter it can drop about 10mm. It would be nice if there was something thicker, as it would increase the damping at the rear (I can't fit rear external dampers in my class). The mixture is basically the same as anti freeze. People have tried using oil, but it rots the rubber diaphragms. Jim. Quote Link to comment Share on other sites More sharing options...
Tony Posted May 12, 2010 Report Share Posted May 12, 2010 Well there you go.... I can see a problem there and i've never even seen the series until you joined the forum. As the fluid heats the.... 1: COG changes 2: The roll centres change 3: The Geometry changes 4: The bump/ rebound values change If you want an advantage with consistency during the race the hydroelastic pressure needs to be controlled. Is it possible to fill the spheres with gas, like nitrogen? Quote Link to comment Share on other sites More sharing options...
metroracerjim Posted May 13, 2010 Author Report Share Posted May 13, 2010 Well there you go.... I can see a problem there and i've never even seen the series until you joined the forum. As the fluid heats the....1: COG changes 2: The roll centres change 3: The Geometry changes 4: The bump/ rebound values change If you want an advantage with consistency during the race the hydroelastic pressure needs to be controlled. Is it possible to fill the spheres with gas, like nitrogen? The sphere's have an chamber at the top filled with Nitrogen, then there are two chambers below filled with fluid. As the suspension compresses the fluid is forced from the bottom chamber into the top chamber. There are valves to control the flow of fluid, and hence the damping. As the fluid enters the second chamber it compresses the Nitrogen, which is acting as the spring. Nitrogen is used for it's greater temperature stability. The rules state the sphere's can't be modified, as it's easy to mess up and hurt yourself, or make something that fails in short order. It is possible to drill through the top and burst the air spring (300PSI!). By welding or braizing a schraeder valve on top you can control the pressure in the spring and stiffen the suspension. Just need to be careful not overheat the rubber diaphragms. To make it really stiff you need a low pressure, as this makes the spring volume much smaller, but again you might have to add some fluid in there to prevent the diaphragm being overstretched. Coilovers would be much simpler. Jim. Jim. Quote Link to comment Share on other sites More sharing options...
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