...anyone done this?

My 7en will be a 100% track-toy never driven on the streets... so noise and vibrations are no problem (i will drive with ear plugs anyway...)... the chassis is completely re-welded and will become a roll cage... the sub-frames are also re-welded... (so that the **** doesn't fall apart the first track-day )

I have the material (7075 T6... seems a "little" bit overkill, but hey, its for free ), the tools (milling machine, turning machine, measurement tools etc.) and the time and motivation...

just looking for some input of someone who has done this before... pictures, hints, tips, problems etc.

thanks in advance

 

You will be better off obtaining or making bushing inserts with spherical bearings that actually allor the suspension pieces to move and are easily replace/repairable. Solid aluminum bushings pretty much went out in the 80's. Delrin bushings are also worth looking into, but again, you would need to make them or have them made. Polyurethane bushings (like the ones I use) are pretty good these days but you still have the issues they have always suffered, which is stiction, binding, etc, making setup a pain.

All of the rear joints could be done with inserts and spherical bearings. for the front you would need to do some pretty insteresting modifications or just have control arms fabbed up.

 

You can buy full sets of delrin bushings these days.

AWR has an example of a front control arm with bearings. http://store.awrracing.com/products/...ront-Left.html

 

i run alum motor, tranny, diff mounts and i DD and autocross my seven in the summer. the vibrations really arn't that bad at all kinda get used to it but i would deff look in to sphehrical bearings for the rest of the sus if ya have the money, i didnt so i run Polyurethane bushings

 

Try super now . they have nice bushings

 

@Dwalker

of course i will use spherical bearings where they are needed... but, for example, i don't need a spherical bearing in the rear subframe chassis mounting points, DTSS points, Trany Pickup etc.

the front control arms are tricky... i've just looked at the rear pickup point and got inspired by the super-now bushings... have to look at the front points tomorow...

I've had poly-bushings in my BMW E36 325i @2.8l and in my BMW E36 V8 swap... I think its time to move on one step

Delrin is nice, but i think i have about 800kg 7075T6 laying around

@farberio

thanks for the hint with the front control arms... didn't know this product by awr yet

@lonewolf

thx, i know all the stuff from supernow! but, i don't wanna spend this much money if i can make my own

 

hah yeah. the car in my driveway right now has all super now suspension parts. pretty good stuff. Just takes a while to get them shipped. If i could make em on my own i would but i dont have my shop anymore. The super now front control arm spherical bearing was kinda a bitch to do but looked nice n clean when it was installed.

 

The aluminum is not self lubricating, so it doesn't suit itself well to sliding items like the suspension bushings. Even if you were to add grease channels and a zerk fitting, you would have to constantly worry about the aluminum getting worn away and loosening in the arms. There's a risk of them getting hot while doing a lot of sliding (suspension cycling on track) and could get hot, causing them to jam up or at least get a ton of stiction.

Delrin and spherical bearings are used for a reason. Nobody yet makes aluminum suspension bushing replacements for a reason.

Use that stuff for all the other bushings though!

EDIT: upon reading, it seems you didn't mention suspension bushings specifically.

 

Aluminum front control arms + aluminum bushings.... I think you will wear out the control arms themselves, especially the front control arm, rear bushing, it will turn expensive. Aluminum will be fine for things such as rear diff/subframe bushing, engine mounts, trans mounts, but not moving parts. I have delrin all around, noisy but happy with them and don't ever have to worry about lubricating them (the front control arm bushings moan sometimes, but a bearing type mount is best used here like AWR's). I only have spherical for the rear control arm and those will be getting replaced by delrin since I hate the noise and worry about them wearing out. Engine and trans are aluminum.

From a design standpoint, the subframe, engine, trans, and diff bushings will be easy to make on a lathe.