chin@ucbvax.ARPA (04/20/85)
From: chin (David Chin) Now that people understand the basic difference between superchargers and turbochargers, maybe the knowledgable can enlighten us about springs. In particular, what are the pros and cons of constant rate springs (where F = kx and k is a constant) versus progressive rate springs (where k is not a constant and instead increases with x)? Also what are the tradeoffs involved in higher/lower rate springs (re: potholes and ride) and how does this translate for progressive rate springs? Since my car has excessive nose dive upon hard stopping, I assume the correct solution is higher rate springs. So how does one go about determining how much stiffer? Finally how do springs rates interact with shocks? If you are not tired out after answering all the above questions, you might also throw in some tidbits on shocks like which brands people prefer (e.g. Koni, KYB, Bilstein, etc.), the pros/cons of gas versus hydraulic shocks, etc. Thanks for the advice, David Chin chin@BERKELEY ucbvax!chin
hkr4627@acf4.UUCP (Hedley K. J. Rainnie) (04/22/85)
I don't know if you want to listen to me since my car has the ride of a roller skate. It's a 71 Corvette. When I upgraded its handling, I went to Chevy. I traded up to the F-41 handling package: 500lb/in spring rate front coils, anti-roll bars front and rear. I basically ordered parts which were originally options from the factory. I don't know much about variable spring rates, but when your suspension travels as little as this one does, I doubt it matters. Potholes and the like are pretty rotten going with this setup, but it NEVER bottoms out, something that my wimpier, older setup did a lot. So, you would probably do well to investigate high performance versions of your car. As far as shocks, Konis all around. And they are amazing. (signed) Speed Racer
vuser@druxt.UUCP (GerardenC) (04/22/85)
>From drutx!ihnp4!ucbvax!chin Wed Dec 31 17:00:00 1969 >Newsgroups: net.auto >Subject: springs? >Message-ID: <6386@ucbvax.ARPA> >Date: Sat, 20-Apr-85 03:52:22 MST >Organization: University of California at Berkeley >From: chin (David Chin) >Now that people understand the basic difference between superchargers and >turbochargers, maybe the knowledgable can enlighten us about springs. In >particular, what are the pros and cons of constant rate springs (where >F = kx and k is a constant) versus progressive rate springs (where k is not >a constant and instead increases with x)? Also what are the tradeoffs >involved in higher/lower rate springs (re: potholes and ride) and how does >this translate for progressive rate springs? Since my car has excessive >nose dive upon hard stopping, I assume the correct solution is higher rate >springs. So how does one go about determining how much stiffer? Finally >how do springs rates interact with shocks? The problem of nose dive is not always caused by spring rate or poor shocks. Both dive and squat can be caused by improper suspension design. the center of gravity in relation to your suspension pickup points will determine the attitude of the car during hard acceleration or braking. Check a race car engineering book for exact explanations. >If you are not tired out after answering all the above questions, you might >also throw in some tidbits on shocks like which brands people prefer >(e.g. Koni, KYB, Bilstein, etc.), the pros/cons of gas versus hydraulic >shocks, etc. I prefer Koni shocks (adjustable) as they do work as claimed and are affordable. I currently have spax ( a British shock) and they do a good job , but they seem to leak. I of course dont mind this since the car is british (no explaination is necessary) > Thanks for the advice, > David Chin > chin@BERKELEY > ucbvax!chin chuck gerarden druxt!vuser
tron@fluke.UUCP (Peter Barbee) (04/22/85)
>particular, what are the pros and cons of constant rate springs (where >F = kx and k is a constant) versus progressive rate springs (where k is not >a constant and instead increases with x)? With a progressive rate spring the incremental displacement decreases assuming a constant incremental force. The advantage is you can load the car with more weight (all other factors being equal). Progressive rate springs may improve handling also, the car should lean less in the extremes. The best part is that in most instances you don't realize you have stiffer springs. The tradeoff is that progressive rate springs cost more and will not necessarily behave predictably as they wear. Assuming the same length spring (linear vs. progressive) the progressive will flex more within a shorter section thus stressing (and wearing) that section of the spring faster than with a linear spring. I might ask the question, why note include the benefits of the stiffer rate spring over the entire range? >Also what are the tradeoffs >involved in higher/lower rate springs (re: potholes and ride) and how does >this translate for progressive rate springs? Higher rate springs impart a rougher ride (all other factors being equal), for progressive rate springs you would need to know what the displacement if to know how stiff they are, and therefore have a means of comparison. >Since my car has excessive >nose dive upon hard stopping, I assume the correct solution is higher rate >springs. I don't agree with your assumption. Stiffer springs will reduce nosedive but a more elegant solution would be to regulate brake line pressure front to back. >Finally how do springs rates interact with shocks? Shocks slow down the velocity of springs. A damper is a device where force is proportional to velocity ( F=bv ), generally the force and velocity vectors are opposite in direction. Thus the shock slows down and evens out the effects of the springs. Peter B