I'd been pursuing 3D printed aluminum, but was juuust shy of making the loads close with the safety factor I wanted. Then I remembered that even 3D printed materials can be heat treated for better properties. Once I punched those properties in to my analysis, the loads closed with some margin. So we're back in the game, after receiving the printed parts I'll just need to do a multi-hour ~450C oven heat treat followed by a quench, then a handful of hours at 100-150C for accelerated aging. The e39/porsche style steel inserts still need to be very strong, 4340 for those.
So back to the dilemma. I've been hemming and hawing about putting a second strut mount up above the first one ever since I saw the amount of camber loss that happens from strut bending (the primary source of camber loss, as it appears). I decided to take some inspiration from the M4 GTS, but figured I could do better by using 3D printing. The F80 M4 GTS knuckle:
This knuckle uses a second strut clamp and some ribs to connect directly back to the wheel bearing. So how can we do better? Well, because we're going to be 3D printing these, we can leave internal voids in places that would never be able to be machined and we can box this entire section out. This should significantly stiffen/support the strut which will provide less hard corner camber loss and also better damper motion (because it's not actively being bent nearly as much). BUT it adds 1lb to each corner, which means I'll effectively come in at the same weight as the stock e46 M3 knuckle, whereas before I was dropping a pound. So what do you all think I should do here, lightweight or stiff?
edit: Here are the heat shield options as well. One simple, one ducted. And as you can see, the gusset acts as the heat shield to protect the strut from radiation:


Leave a comment: