Black & Tan 332iT

[maupineda]

Hi Bryson, sorry if I missed it but, besides the material weight benefit, why did you choose e60 design?

[Bry5on]

I'm sadly out of town this weekend, but decided to check for clearance in the printer here at home. The knuckle is rather conveniently sized..


This model is 2kg (4.4lb) in aluminum and has a minimum safety factor of 4 under a 2G braking case and 1.6G cornering case.

[Bry5on]

Is this an optimal model generated by CG? The geometric complexity in areas like the tie rod mount look really difficult. Looks like you could keep 10% more material and simplify the shape, no? Cool nonetheless.

Yeah you’re right - can definitely make it simpler at very little weight penalty. I’ll run a few more simulations and computer generated designs then probably CAD a human-made version to compare stiffness and strength properties. I’ve been basically just adjusting the keep-outs and letting the model chug. There’s a new run waiting for me to get home and inspect. You can see how the BMW design sub-optimizes deflection for ease of manufacturing, they definitely left some performance on the table in those castings.

This computer generated knuckle may even be small enough to print in my home plastic 3D printer as a mockup, which would be pretty cool, and a handy validation for metal 3D printing.

Before I finalize this, I’ve still got to design a mount for a heat shield and a basic duct for brake cooling. I *think* I can make that from a single brake formed piece of aluminum at this point, but we’ll see.

[YoitsTmac]

Is this an optimal model generated by CG? The geometric complexity in areas like the tie rod mount look really difficult. Looks like you could keep 10% more material and simplify the shape, no? Cool nonetheless.

[Bry5on]

Okay a little practice and I'm getting better. Once you start adding all the keepout spaces for bolts, wrenches, ratchets, AND sensor and install direction, control arms, tie rods... you can see how BMW arrived at the e60 'bowl' shape design. I'm a few simulations in now and they're all coming in around 2-3kg with 4-7x safety factors in printed/machined aluminum and 5-15x safety factors in Ti. I used some pretty hefty loads, like 2G in braking and 1.6G cornering to build the model. I'm sure there's lots of mass optimization to be had here, but since I'm really trying to optimize for stiffness without invalidating strength, Ti probably won't be much of a benefit at all over Al, practically speaking. I'll keep you all posted.


Example aluminum solves

[Bry5on]

Okay, I couldn't help myself. I'm going to try the built in generative design tool in Fusion. Looks like the e60 hub will package within the e46 available space..

[Bry5on]

Made some progress modeling bank 2:


Interesting to note that as George Hill pointed out - the US bank 2 header crosses over to the *passenger* side of the car, where the euro bank 2 header stays on the *driver* side of the car. Odd!

Edit, some details:
Tube is 40mm OD, 1.5mm wall (37mm ID) and all bends in bank 2 are 40mm radius
Runner length is somewhere around 320mm when you include the length of the exhaust port
A post-step size of a 5/8" OD, .065" wall should work well with the stock pipes
I just purchased an exhaust textbook so that I don't royally screw this up.

[Bry5on]

Thanks to a fellow member here (thank you!), today I got a good scan of a front suspension knuckle for a future project. Figured I'd make it available here for anyone who wants to use it for design purposes: https://s.digital3dcloud.com/space/f...lang=en&loop=1

[Bry5on]

Progress. What's next.....

[Bry5on]

Another couple hours, trying a different technique that's easier to model but basically has to be 3D printed instead of mandrel bent. I'll probably end up doing both techniques in the end, the easier to model for mockup and the easier to manufacture for final version. Bank 2 on the left in the photo is equal length, again just practice. You can see I'm working to get the hang of keeping fastener and tool clearance for installation.

[davidinnyc]

It's all those throttle blip downshifts with the smooth tune

I need this soon!


Sent from my iPhone using Tapatalk

[Bry5on]

It’s all those throttle blip downshifts with the smooth tune

[0-60motorsports]

...or Bryson sends it harder than anyone else on the boards!

lol maybe

[davidinnyc]

The plastic probably got brittle by age and heat.

...or Bryson sends it harder than anyone else on the boards!

[Bry5on]

First couple hours in Fusion 360 logged. Rough but it's a start.