E86 Front Triangulation Braces Retrofit

[YoitsTmac]

Amazing project and effort! Can't fully say how much I appreciate this. Hopefully more people will get to use this diy for their cars and change the car for better.

I have a question. What is the reason to use or start with OEM aluminum strut brace? Are not there better and way stiffer 3piece alternatives like DMG or so? Since you can also remove the middle section of the brace for easier serviceability.
I understand that in an event of crash stiffer braces may damage the car more. But was it so big priority or you think there is not much of a stiffness available to be gained?

I actually asked my coworkers boyfriend about this, who's a lead chassis designer at a world-renown automotive manufacturer. Wish I still had his big blurb, but basically, the gain by merely tying it in is so substantial, that as long as your tube stiffness is reasonable, the gains switching materials is so marginal it wouldn't be recognizable. He then said I could do it in chromium, but we didn't talk about temperature. There is tension fatigue, but the bar itself is so cheap it hardly comes into consideration.

[heinzboehmer]

Still have some finishing work to do. Now on to figuring out the strut mounts and mounting the bars. The challenge here is serviceability. I would like the two new braces to mount under the OEM bar so it is less to remove if I need to remove the intake manifold.

I am also going to do the strut tower mounts in long strand forged carbon. I am leaning towards making them thinner like Heinz’s process to fit the 3rd lug so I can make a plate which goes between the cross bar and the strut plates. Then bolt the triangle braces to the plate…like Heinz’s design.

Or maybe I mount the two braces under the strut tower plate and run a bolt through…

Hell yeah! I'm excited to see the design you come up with.

Amazing project and effort! Can’t fully say how much I appreciate this. Hopefully more people will get to use this diy for their cars and change the car for better.

I have a question. What is the reason to use or start with OEM aluminum strut brace? Are not there better and way stiffer 3piece alternatives like DMG or so? Since you can also remove the middle section of the brace for easier serviceability.
I understand that in an event of crash stiffer braces may damage the car more. But was it so big priority or you think there is not much of a stiffness available to be gained?

Yeah, like you said, I went this route mostly for crash safety.

Designs like the DMG bar are useful because they help reduce strut tower fore/aft deflection (relative to the other strut tower) with the torsionally stiffer bar. However, tying the strut towers directly into the firewall (which is essentially immovable in comparison) constrains the fore/aft deflection, so I don't think there's much to be gained from a stiffer middle bar.

Also, both the E46 and E86 braces are notched and designed to fail before anything else in a crash. Since they don't fail during normal use, there is likely little to be gained by upping the stiffness of each individual part.

I actually asked my coworkers boyfriend about this, who's a lead chassis designer at a world-renown automotive manufacturer. Wish I still had his big blurb, but basically, the gain by merely tying it in is so substantial, that as long as your tube stiffness is reasonable, the gains switching materials is so marginal it wouldn't be recognizable. He then said I could do it in chromium, but we didn't talk about temperature. There is tension fatigue, but the bar itself is so cheap it hardly comes into consideration.

Glad to hear that coming from someone with the appropriate credentials!

Also, temp data coming soon:

[heinzboehmer]

Some updates on the remaining bits of this project in my journal, in case anyone wants to follow along with the development: https://nam3forum.com/forums/forum/m...477#post324477

Track day coming up, so should have some solid temp data next week for you guys. Preliminary data is promising.

Also, printing up the first full scale prototype of the modified cabin air filter housing as we speak. Hoping that the design for that doesn't need too many iterations.

[heinzboehmer]

Track day thermocouple results are in!

The max temp the windshield mount saw was 65.5 C, but at steady state, it hovers right around 40 C.

This means that the part will see essentially no temp degradation at that location. Rest assured that the 7075-T6 version will not spontaneously fail on you

For anyone curious, here's a more detailed analysis of the data: https://nam3forum.com/forums/forum/m...636#post327636

[CrisSilberGrau]

If there's a list for parts order for this project to bring the cost down per piece, let me know please.

[bigjae46]

Does anyone have the outer diameter of the E86 braces?

[heinzboehmer]

Does anyone have the outer diameter of the E86 braces?

25mm

[bigjae46]

25mm

Fack! I store my car at the track, 40 min away and I forgot to measure how long.

Could you hook a brother up with the length too? Damn I'm a pain in the ass! 🤣🤣🤣

[heinzboehmer]

Fack! I store my car at the track, 40 min away and I forgot to measure how long.

Could you hook a brother up with the length too? Damn I'm a pain in the ass! 🤣🤣🤣

Lol all good.

My design puts the brace mounting studs 555 +- 10 mm apart.

I don't really know how long a stock E86 brace is, as the ones on my car have been shortened a but. Guessing stock is closer to 600 mm.