E86 Front Triangulation Braces Retrofit

[heinzboehmer]

Alright I'm calling this project (including documentation!) 99.9% done. Just have two small TODOs to get through before I can call it 100%:

1. Weigh the modified cabin air filter housing/firewall plug + a stock cabin air filter housing and add to documentation.
2. Sand and paint the strut tower brackets.

Documentation and files in the drive are up to date. Most changes revolve around the cabin air filter housing/firewall plug, as those weren't fully finished last time around.

Feel free to read through and provide feedback!

Couple pics of the newly finished parts:

[bigjae46]

Hopefully I get this all made and installed before the end of the decade...

First CF strut tower plate attempt. Went better than expected!





To my credit it looks like a strut tower brace. The spot where the triangle brace bolts to...I wasn't thinking and the threaded insert was too deep so that prevented complete closure of the mold. Then I use unchopped carbon tows and it was totally monstrous to work with. There were some details to the part that made it hard to get the carbon into place. The underside of the part is missing some details.

This part seems to be plenty strong and sturdy enough. I'm thinking I need to build up with regular cloth and then top it off with some chopped carbon.

Hope to get the firewall mount bonded in this weekend.

[bigjae46]

Word is that Slon tested this part on his chassis rig and it made near as no difference. If it does make a difference I’d bet it would be on cars with big front sway bars. Like lowered cars with destroyed front suspension geometry

That wouldn't surprise me. The upper half is riveted to a steel bracket which is riveted to the lower half. If anything, I think it would sense to tie into the lower part or the frame rail or make the entire frontend clip much beefier.

[___LUNK]

How about tying to the engine block and making it a stressed member of the chassis F1 style

[Bry5on]

Word is that Slon tested this part on his chassis rig and it made near as no difference. If it does make a difference I’d bet it would be on cars with big front sway bars. Like lowered cars with destroyed front suspension geometry

[bigjae46]

I've seen a core support from a convertible e46 and it didn't look like the flimsy stamped metal piece like the coupe / sedan, it was much more rigid. Maybe that's an option?

Weird..same part part for M3 convertibles and the M3 sedan and non-M except for convertibles...

RealOEM.com - Part Search

Here is the convertible part #. Looks like it is plastic with some stiffening ribs on the underside which the metal part does not have. And it only costs $900!

RealOEM.com - Part Search

[Will]

Not sure it will do much since the core support is quite flimsy.

I've seen a core support from a convertible e46 and it didn't look like the flimsy stamped metal piece like the coupe / sedan, it was much more rigid. Maybe that's an option?

[heinzboehmer]

Not sure it will do much since the core support is quite flimsy.

Would for sure need to further triangulate from the core support down to the chassis rails. Basically emulate what BMW does in their newer cars with those fangs/nose hairs you can see through the kidneys.

Hard to say how much it would be worth it though. Would be interesting to grab one of those newer cars and measure chassis rigidity with and without that bracing installed.

[bigjae46]

Next up: triangulation to the core support? Food for thought...

Not sure it will do much since the core support is quite flimsy.

[heinzboehmer]

Is there space in the E46 engine bay to weld an additional bracket onto the strut tower like the Z4 had originally?

That was my initial idea and unfortunately it requires even more work. The corner bin firewall divider things, the strut tower brackets, the engine harness box and the jump start point all get in the way:




I did, however, notice that they fit pretty great if you put them pointing forward:



Next up: triangulation to the core support? Food for thought...

[___LUNK]

Is there space in the E46 engine bay to weld an additional bracket onto the strut tower like the Z4 had originally?

[Bry5on]

I hope the sentiment of my post didn’t come off as a knock on the work done either haha.

I do like the idea of a carbon version akin to the OE M-performance or the strut bar although this would be counterproductive cost wise. Going to talk to a couple friends in aerospace mfg to see if they can CAD this idea further and give insight onto manufacturing prices. Something similar to the Dinan E90 m3 triangulation bars would be awesome.

You have now come full circle to the Slon design

[heinzboehmer]

Totally agree that a fully machined part is the way to go. Lighter, simpler, easier to install, all the good things.

I was pretty burnt out on the CAD work by the time I got to those parts, so decided to go the simple route with the sheet metal parts. Getting the design to look like the stock parts sounds like it requires a decent chunk of work. If someone else designs this, please share! Would love to move to that solution.

And yes, definitely need to paint mine black. They stick out a lot and I don't like it. Will get to that soon.

[ParliamentLights]

Not knocking the current design. I just think there is probably a simpler single piece way to do it. It may require deviation from the Z4 rods though. Not really sure til I dig into it a little more.

I hope the sentiment of my post didn’t come off as a knock on the work done either haha.

I do like the idea of a carbon version akin to the OE M-performance or the strut bar although this would be counterproductive cost wise. Going to talk to a couple friends in aerospace mfg to see if they can CAD this idea further and give insight onto manufacturing prices. Something similar to the Dinan E90 m3 triangulation bars would be awesome.

[bigjae46]

Not knocking the current design. I just think there is probably a simpler single piece way to do it. It may require deviation from the Z4 rods though. Not really sure til I dig into it a little more.

I didn't take it as a knock on the design. I'd like to see someone analyze a carbon part and engineer the layup to improve the strength. Especially how to secure the bars to the part.

I am using some knurled threaded inserts. The carbon/epoxy is compressed against the inserts so I think it should hold up to being torqued, twisted, and stressed. Would be nice to have some idea on whether this will actually work before live testing it.

threaded inserts | McMaster-Carr