[SD Convert]

I'm looking at doing this upgrade to replace the aftermarket strut tower brace on my 430i. This is to get better engine access (the dealer charges me 1/2 hour to remove and reinstall it if they determine it's in the way).

It appears that the Carbon Fiber brace has fitment issues on 4-cylinder engines, so I'm not doing that at this time. Even without this, I expect the additional fender attachment points will give me more structural rigidity than I currently have.

The corner braces to the A-Pillar are currently running a total of about $450, not including the custom frame attachment. I think I'll leave this out for now as well. If there's a problem, I'll look into it.

Since I've got a convertible, the bottom bracing is already in place.

I'm wondering about the windshield panel covers. If I'm not using the CF brace, do I still need to replace them?

I'm also looking at getting a step washer created to go on the top of the strut shaft to keep it centered in the guide support bearing. I think I know a place that would be willing to make this from 17-4PH stainless at a "reasonable" price (they have in the past, but who knows what they'd charge today). I'll be replacing my struts as part of this upgrade, so I'll have all the parts available before hand for fitting.

Finally, does anyone know if I can keep the factory strut brace (51-61-7-378-711) for some additional structure?

Thanks in advance.

[SD Convert]

If anyone is interested in the A-pillar bracket that the struts in Stage-4 connect to, here's some additional information:

F30 bracket
Left 41008063227
Right 41008063228

F32 bracket
Left 41008063221
Right 41008063222

According to RealOEM, these brackets are used on the F80 and F82 from 2012 to 2018/2019. The panel they're attached to is the same for F30 & F80 and F32 & F82. These should work for those cars.

Just to be complete, zipphreak lists parts 41217284399 (left) and 41217284400 (right) for the M2 Coupe.

These brackets would need to be welded on or attached with a structural epoxy. In both cases, some repaint would be needed.

[SD Convert]

Originally Posted by SD Convert

I'm wondering about the windshield panel covers. If I'm not using the CF brace, do I still need to replace them?

This mod replaces a grommet in the fender with a nutsert. The F33 (and I assume the rest of the F3x bodies) use a positioning pin inserted into that grommet to position the windshield panel covers. To get the windshield panel covers to fit (not properly, but fit at all), the positioning pin that goes into the grommet needs to be removed. After removing that pin and cleaning up around it, they fit, but I think the windshield panel covers listed in the OP would fit better.

Originally Posted by SD Convert

I'm also looking at getting a step washer created to go on the top of the strut shaft to keep it centered in the guide support bearing. I think I know a place that would be willing to make this from 17-4PH stainless at a "reasonable" price (they have in the past, but who knows what they'd charge today).

The place I had in mind (Totally Stainless - great place for stainless fasteners) doesn't do this anymore. I found a local machine shop that came highly recommended. They created the step washers (see attached PDF). These go on top of the strut shaft. They center the shaft in the guide support bearings and spread the load a bit. If I had to do this again, I'd make the main thickness 2mm instead of 4mm. There would be no difference in cost but there would be a few more threads above the strut nut.

If anyone is interested, I have a few spare step washers that I'd be willing to let go.

Originally Posted by SD Convert

does anyone know if I can keep the factory strut brace (51-61-7-378-711) for some additional structure?

The holes that it bolts to on the guide support bearing are gone (I knew that when I started this) and there are no other mounting holes that will work, even if I bend the support.

[E90lova]

I always knew this chassis was crap. All these braces required to make the chassis feel like any current chassis from other German manufacturers today. An Audi A6 C7 feels way stiffer than my F30, also the B8.5 Q5 I had and the A4.

[TurboWeasel]

Originally Posted by SD Convert

If anyone is interested in the A-pillar bracket that the struts in Stage-4 connect to, here's some additional information:

F30 bracket
Left 41008063227
Right 41008063228

F32 bracket
Left 41008063221
Right 41008063222

According to RealOEM, these brackets are used on the F80 and F82 from 2012 to 2018/2019. The panel they're attached to is the same for F30 & F80 and F32 & F82. These should work for those cars.

Just to be complete, zipphreak lists parts 41217284399 (left) and 41217284400 (right) for the M2 Coupe.

These brackets would need to be welded on or attached with a structural epoxy. In both cases, some repaint would be needed.

For the benefit of others considering this mod, the parts above are obsolete, for the F3x at least.

Well, technically they're on back order, but from past experience with BMWs and other German cars, back ordered generally means they won't commission another batch unless there's sufficient demand.

Interestingly, the M2 doesn't use the A shaped struts that attach to the A pillar in the pictures I've seen, so I'm not sure if dropping them from an F3x would be detrimental or not? Just the aluminium brace on mine seems to contribute a noticeable improvement. Nothing dramatic, but owners would notice it. Average Joes wouldn't.

Someone mentioned rivnutting that area but I don't think that is a good idea. For starters the hood has to come off in able to get a drill squared up, and secondly, the panel isn't man enough for it, hence the bracket BMW fashioned for that job. The tension strut mount also wouldn't sit flush onto the rivnut as the angles are all wrong.

I also get the knocking Lancelot mentioned sans the A pillar tension struts, although I don't really understand why that would be the case? As a guess, it could be the brace pressing onto the ABS pump bracket as there is no clearance for it in F3x cars. It could also be the M3 top mounts as the rubber buffer is much stiffer than the F3x's top mounts.

So I've parked that bit of the project for now. It was an interesting thing to do fitting the brace and M3 top mounts from a hobbyist point of view, to satisfy a curiosity, but knowing what I know now, it's not something I would bother with again as the improvements nowhere near justify the cost and hassle - on the F3x platform at least.

[Antwanr942]

I see the brackets 41217284399 (left) and 41217284400 (right) are present on all F22/F87 (including the M235IR) however I don't understand how the extension rods actually attach to it. There is a "mounting point" but its just a hole in the metal, no thread or anything like that. Unless a nut is to be used. Perhaps I'm misunderstanding how this bracket works. Looking to do this retrofit to my 240i but I want to have the extension rods for the sake of completeness.

View post on imgur.com

[TurboWeasel]

Yeah I'm the same, I want at least the upper half to be complete and then I can add the lower U brace at a later date if I want to.

I'm not sure what that F22/F87 bracket is for but it doesn't look man enough for an M10 bolt/nut.

So I had some time off work and revisited the A pillar tension rods. In the end I had to just fashion some brackets, which was tricky as I don't have a garage or access to 3D scanning or printing.

Rather than taking the hood and fenders off to get spot welding tools in there, I chose to use structural adhesive instead. 3M DP420.

In hindsight I would have chosen a faster curing one as it's quite runny and gets everywhere, but as it's all covered over anyway, the look of it doesn't bother me.

The glue is ridiculously strong but if it does detach from the A pillar, I'll have to bite the bullet and take it to a body shop for spot welding. I did lever on the tension bar as hard as I could and the whole car moved, so I think it will hold.

I don't know what the purpose of the tension rods is to be honest, but BMW went to the trouble and expense of R&D'ing them, so they must serve a purpose.

By far the hardest part was getting the angles right for the tension rod to sit flush on the bracket. It's all very awkward angles and very tight access but I got there in the end.









So the knocking I was getting was actually to do with the dampers not playing nicely with the F80 top mounts. Initially I tried M12 to M14 adapter sleeves but they didn't work out.





So I did it the OE way and made up these little ring sleeves instead and press fitted them to the dampers. I then just got some M12 to M14 threaded adapters to take the F80's top nut.





It's a lot work for seemingly minimal gain but the upper brace with the tension rods does make a noticeable difference. It was worth it as an experiment, especially as all the brace parts were dirt cheap from ebay, but I'm not sure I would do it again

[TurboWeasel]

After 200 miles of hard driving, the structural adhesive is holding up just fine. Zero signs of movement or cracking. It definitely is a viable alternative to spot/plug welding.....meaning it can all be done in situ without removal of the fenders and hood.

If you can be bothered to make up some brackets, I recommend going for it.

The best way I can describe how the car feels now is like a factory fresh rigid shell vs a 10 year old one that's suffered a decade of jacking up, pot holes and other torsional fatiguing. And that's just from the upper half. The U brace is supposed to stiffen it up even more.

[Not A M4]

Originally Posted by Steve_Jr

Hello. There are 4 stages if you want to install M4 carbon strut brace on F32 4 series.

Stage 1 M4 Support bearing reinforcement ring
Stage 2 M4 Alloy center strut brace + M4 support bearing
Stage 3 M4 Carbon (CFRP) strut front end
Stage 4 M4 Extension suspension cross brace + Diagonal strut

My 2014 428i (N26) already has Ohlins R&T MP00 suspension and M4 genuine 437M wheel + PSS 235 / 265 tire. Currently Stage 3 completed .. Enjoy !!



Here we go : Both Beinforcement ring and Guide support bearing need to be matched with production year of yours. from 2015 it's changed from M10 3 hole to M8 5 hole.


Stage 1 M4 Reinforcement ring for Guide support bearing

~ 2014 : used M10 x 3 hole
Reinforcement ring, left : 31302285700
Reinforcement ring, Right : 31302285701
Hex screw M10 6 EA : 07119904141

2015 ~ : used M8 x 5 hole
Reinforcement ring, left : 31302361991
Reinforcement ring, Right : 31302361992
Hex screw M8 10 EA : 31307855400


Stage 2 M4 Alloy center strut brace + M4 support bearing

~ 2014 : used M10 x 3 hole
Guide Support bearing 2EA : 3130284702
Alloy Strut brace (left steering) 1EA : 31122284855

2015 ~ : used M8 x 5 hole
Guide Support bearing 2EA : 31307853702
Alloy Strut brace (left steering) 1EA : 31127855855

Torx bolt M10 (alloy SB - top) 56Nm 2EA : 31106854219
Torx bolt M8 (alloy SB - mount) 28Nm 6EA : 31106859809
Fillister head screw M10 (alloy SB - edge) 34Nm 2EA : 07147162464
Blind rivet nut, flat headed 2EA : 51718065070
Cover, windsheild panel, Left : 51718059699
Cover, windsheild panel, Right : 64318059697
Engine hood sealing, Left : 51768058561
Engine hood sealing, Right : 51768058562
Expanding rivet 6EA : 51118174185


Stage 3 M4 Carbon (CFRP) strut front end

CFRP strut front end 1EA : 51618061631
Cross link (only Coupe & Sedan) 1EA : 51647294928
Hex bolt M8 (CFRP - front) 28Nm 2EA : 22326760945
Hex bolt M8 (CFRP inside) 28Nm 6EA : 11287839136


Stage 4 M4 Extension suspension cross brace + Diagonal strut

Extension Strut Tower, Left : 31122284857
Extension Strut Tower, Right : 31122284858
Link, Left : 31122284859
Link, Right : 31122284860
Torx bolt M8 2EA : 07147248303

Bottom reinforcement option only for sedan, coupe (Convertible already installed)

Stiffening plate 1EA : 51617299690
Torx bolt M10 2EA : 07147313416
Diagonal Strut 1EA : 51647294929
Adapter plate 1EA : 51647311426
Tort bolt M10 2EA : 07146959643
Hex bolt M8 4EA : 07147321202

No.1 BMW tuning forum www.bimmerwerks.co.kr

Do you know if these plates added any camber? and or if the M4 GTS plates add any camber?