Blackfrogg 1 Report post Posted January 5, 2016 Anyone certed true coilovers in the rear of their e30? Cert man wants some FEA or practical testing done to show its safe/how much reinforcing the strut tower needs. If anyone has done this before would you be able to help me out? Would be great if someone has test results already that I can use and save myself some $$$. Thanks Quote Share this post Link to post Share on other sites
hybrid 1039 Report post Posted January 9, 2016 The stock rear shock towers aren't engineered to handle both shock and spring load. You will need to reinforce the tower and brace it properly so it doesn't mushroom and stress crack after a period of time. A few of the older members on here have done it and can better explain it. I stuck with semi trailing arm and spring setup however put some ground control reinforcement plates and rear strut tower cross brace in because of my harder shocks, mine isnt full rear coil over however. Quote Share this post Link to post Share on other sites
MLM 57 Report post Posted January 9, 2016 FEA is going to be a complex and difficult thing to do right. I suspect the cert guy has suggested it only because he is aware of it as a tool for stress analysis and probably doesn't understand the complexity of doing it right. Most mortals don't have the $$ or computing power to offer a real answer For a FEA to be done properly you will need to know the material thickness, type/grade, local existing connection strength ie spot welds? bonded? again what strength, single skin mullti skin let alone the accurate CAD to support this. You will need to know string rate for loading, assuming no solid loading is applied ie bumpstops and design this all to avoid fatigue etc. This will give you an indication of what's required. unless you did further testing to validate any assumptions. This work is long and complex to do right. For example your new design may be 4x stronger, but stronger than what? is the original strength known? Is the new design strong enough? Sorry im off on a tangent here but deal with this daily at work. One would hope the cert guy can be shown existing examples of structures which work in this configuration, and apply engineering judgement. Build it blatantly strong along side some known functioning examples will prove every bit as much and more than a FEA exercise. Hopefully some members can share their examples of what works. Quote Share this post Link to post Share on other sites
