Slon Workshop E46 M3 Carbon Front Triangulating Reinforcement Kit

[jet_dogg]

Bryson's pics and impressions from his thread were lookin kind of tasty with the black on a black chassis because the eyes don't focus on the contraption.

I've got some dough burning a hole in my pocket so I may have to pull the trigger one of these days.

[Casa de Mesa]

I've got some dough burning a hole in my pocket so I may have to pull the trigger one of these days.

DO IT, BRUH!!!!!

[blazenXLT]

Looks great. Maybe I missed it, but does the entire assembly need to be removed to get the valve cover off?

[jet_dogg]

DO IT, BRUH!!!!!

When I get bored it's trouble I tell ya!

I've bought worse things for more.

PS. Don't enable me broseph.

[Casa de Mesa]

PS. Don't enable me broseph.

I'm just looking out for you. I mean... we already have confirmation it looks incredible on black (or close to it) cars.

[jet_dogg]

I'm just looking out for you. I mean... we already have confirmation it looks incredible on black (or close to it) cars.

I prefer the look of the dmg but nobody said I can't have both. I don't like the idea of epoxy much like the strengthening wall but I'd never remove them in all likelihood so there's that.

I also like having backups 😂

[Obioban]

Looks great. Maybe I missed it, but does the entire assembly need to be removed to get the valve cover off?

The extra labor for valve cover will be the entire strut tower brace (instead of just the center portion) and the adapter bracket. Will probably add 3-5 min to jobs that need that.

[Obioban]

DIY!

I know the car is dirty. I’m currently building a house, and the driveway isn’t paved yet. Keeping the car clean is just a non starter at the moment.

This was actually a pretty easy project, if slightly scary because you only get once chance to bond the part correctly. The entire project took ~3 hours of labor, taking my time, but with a 24 hour block in the middle where I let the epoxy set. There’s a lot of doing/undoing/redoing, but once the part is installed you won’t have to deal with that again.

I’m going to steal some pictures from the SLON Workshop instructions and use some of my own.

The project basically has 5 phases:
1. Disassembly
2. Prep work
3. Test fit
4. Epoxy, partially assemble, tighten
…
(wait epoxy cure time)
…
5. Disassemble and reassemble with all the non bracing parts (firewall plug, cabin air filter housing) installed

The project should be completed with the weight of the car on its wheels (not jacked up). The flatter the surface you can do it on, the better, though that’s less critical than having it on it’s wheels— that’ll let the suspension level the load as much as possible, so you’re not bracing the chassis in a tweaked position.

1. Disassembly

Remove all the stock parts- stock strut tower brace, stock cabin air filter housing, stock firewall plug, wiper arms, and the lower windshield cowl (just pull straight up to remove this, it’s push pins). The only part that was a bit tricky here was removing the wiper arm, perhaps because they’ve never been removed from my car in 19 years. Prying is NOT the option to go for here, because the surface below is the glass of your windshield. What I found worked perfectly was a valve spring compressor I bought a while back to rebuild my lawnmower engine— IIRC the tool was $10 at Advance Auto Parts.



2. Test fit

I would not skip a test fit! Couple of reasons to do it:
a) if your chassis is tweaked, better to know this won’t fit BEFORE you epoxy pieces in
b) Next time you do this, it’ll be under the time pressure of setting epoxy. Good to have a practice run under your belt.

There are 5 M8 bolts that come with the kit, of 3 different types.



Bolt 3 attaches the the mount bracket to the car while the epoxy sets. Take Bolt 3 and use it to temporarily loosely (so that it can still move) affix the mounting bracket (plate that gets epoxied in) behind the center wind shield cowl hole:



Install the strut tower brace (reusing the stock strut tower brace hardware, and install the adapter bracket between them. Bolt 2 (2X) in the picture above goes between the strut tower brace and the adapter bracket. Bolt 1 (2X) in the picture above goes between the mount bracket and adapter bracket.



Tighten all hardware to 25 nm, check fitment. Assuming everything fits properly and you feel comfortable with how everything bolts together, it’s time to move on to….


3. Prep work

Take the adapter bracket and strut tower brace out.

Close the vents on the HVAC system to prevent debris from falling in. With gentle but steady pressure you can close the fresh air doors on the heater case to keep debris/sanding dust out of the HVAC system while working in the area.

Use a marker to trace the edges of the mount plate on the metal. Remove the M8 Bolt and mount bracket. Put down some sort of drop towel or paper so that paint/metal dust don’t get into your climate control system area. Use 180-220 grit sandpaper to sand within the area you marked. You don’t have to get down to bare metal, but you do have to get through the paint and into the primer.



The kit includes a plastic wedge— you can use this to sand the areas that are difficult to get into with your fingers:



Don’t half ass this step— it’s what will give your plate a good bond.


CSL Airbox only step 3B:
If you have a CSL airbox, you will need to replace the check valve on top with the one SLON includes with the kit.
If you have a stock airbox, ignore this step and set the check valve aside for when you inevitably get a CSL airbox.




4. Epoxy time

First off, practice inserting the mount bracket in such a way that you won’t wipe off the epoxy as you insert it. I found that if you hold the bracket at ~45º to the firewall, and insert it right at the bolt location, you can do so without any contact.

Next, lightly grease the threads of bolt 3. It will be removed after the epoxy sets, and that’s not going to be easy if it’s structurally adhered. But, you don’t want to use so much that it overflows out of the threads, either.

Finally, change your greasy gloves and prep the parts. Use a degreaser to throughly clean the area you sanded as well as the bonding surface of the mounting bracket.

Look over everything, make sure you know where everything you used for the test fitting is. Squirt a little epoxy out of the mixing nozzle, in case the initial bit isn’t mixed. Then, apply your structural adhesive to the mounting bracket mating surfaces:



More from Bry5on, as he is far more experienced with this kind of bonding than me:

For degreaser, I used acetone followed by IPA on the metal, always wiping in one direction with clean towels! For carbon, I did a very light abrade then a wipe with IPA.

I’d also recommend wetting out the surface of the bracket and where it mounts with a thin coat of epoxy. This will help guarantee a good adhesive bond. Then run your fingers around the squeeze out to create a nice fillet. You’ll have a bit messy of an install since access is tight, but this should ensure you get a good bond. I took pics of this, you can see it’s a little messy.

Pics

With that, the race is on.

a) use your practiced gesture to insert the mount without smearing the epoxy off. Fasten lightly using the (now greased) bolt 3. The goal here is to get this snug enough that it can hold its position, but loose enough you can still move it around a bit as you install the other parts. Use the included plastic wedge under the rear of the mount to ensure good contact between the rear of the mount and metal:





b) install the strut tower brace. As much as possible, center it left/right between the towers. Don’t tighten yet.
c) install the adapter bracket between the mount and strut tower brace
d) make everything snug, not tight (so parts can move as other parts are fully tightened down)
e) tighten in the following order:
1) strut tower brace bolts (6X)— 24 Nm
2) strut tower brace to adapter bracket (2X) - 40 Nm
3) adapter bracket to mount (2x) - 40 Nm
4) mount to firewall— 30 Nm
The goal here is to not create any tolerance stack ups here that’ll bite you down the road— so use the ability to slightly tweak where the mount is adhered to the firewall to make sure you have good fitment in the future.

——————————————————
With that complete, let your heart rate settle. Instead of wanting the epoxy to cure more slowly, now it can’t happen soon enough. Let the adhesive cure.
——————————————————

5. Assembly isn’t opposite of disassembly.

Take everything out again, other than the epoxied in bracket. But, do remove and discard the 8mm greased bolt that held it the mount in place as the epoxy cured. Don’t forget to remove the plastic wedge you jammed under the mounting bracket!

Parts have to go together in a very specific order. Failure to do so will result in you doing it twice.
a) install the (cork/CF) firewall plug. Note that the squares on the mount brackets key into the squares on the firewall plug. Align the keyed squares first, then use fasteners (either stock or the ones included with the kit) and included circular spacers to secure the firewall plug in place, holding that keyed location. Reinstall the hardware that attaches the side pod plastic trim to the firewall plug. Reinstall windshield cowl.
N.B.: use the included circular spacers between the firewall plug and firewall at the hardware wall location.
If you don’t use the spacers, the firewall plug will likely crack. If you don’t align/key the firewall plug square to the mount bracket, you’ll have changed your clearances and it won’t go back together.





b) reinstall, for the last time, the strut tower brace. Don’t fully tighten.
c) run the 2 wires (that get attached to the cabin air filter housing) over the strut tower brace
d) install adapter bracket, loosely. Fully tighten strut tower brace to strut towers (25 nm). Fully tighten adapter bracket to mount bracket (40 nm). Fully tighten adapter bracket to strut tower brace (40 nm).
e) remove bolts that attach adapter bracket to mount bracket
f) transfer gaskets/drains from stock cabin air filter housing to new, SLON version. install cabin air filter housing. The two center fasteners are the fasteners that attach the adapter bracket to the mount. Insert the two included square spacers through the cabin air filter housing, keying them into the mount bracket. Install the two bolts that attach the adapter bracket to mount bracket for the last time, and tighten to 40 nm.



g) insert cabin air filter
h) transfer pins from stock cabin air filter cover to SLON CF version. Install
i) run the engine wires through the SLON wire guide and clip the cover into place.
j) reinstall wiper blades


Complete.

[George Hill]

Remove all the stock parts stock strut tower brace, stock cabin air filter housing, stock firewall plug, wiper arms, and the lower windshield cowl (just pull straight up to remove this, it’s push pins). The only part that was a bit tricky here was removing the wiper arm, perhaps because they’ve never been removed from my car in 19 years. Prying is NOT the option to go for here, because the surface below is the glass of your windshield. What I found worked perfectly was a valve spring compressor I bought a while back to rebuild my lawnmower engine— I think the tool was $10 at Advance Auto Parts.

You can get the arms off by hand and without the tool but I have seen people break windshields, but their are lots of options for "Wiper Arm Removal Tool." But really I'm impressed that your windshield cowl trim is original, didn't think they made it more than 4-5yrs. ha

The kit includes a plastic wedge— you can use this to sand the areas that are difficult to get into with your fingers:

With gentle but steady pressure you can close the fresh air doors on the heater case to keep debris/sanding dust out of the HVAC system while working in the area.


Looks great and seems like a very simple process to get installed.

[Casa de Mesa]

You can get the arms off by hand and without the tool but I have seen people break windshields, but their are lots of options for "Wiper Arm Removal Tool."

I was able to get one of mine off without the tool, but struggled with the 2nd and nearly popped the windshield. For the $10 in the cost of the tool, I highly recommend anyone who hasn't done this before just get the tool.

With gentle but steady pressure you can close the fresh air doors on the heater case to keep debris/sanding dust out of the HVAC system while working in the area.

Great tip, wish I had known that when I was working in this area. I taped mine up but would have rather just closed it!

[Obioban]

You can get the arms off by hand and without the tool but I have seen people break windshields, but their are lots of options for "Wiper Arm Removal Tool." But really I'm impressed that your windshield cowl trim is original, didn't think they made it more than 4-5yrs. ha



With gentle but steady pressure you can close the fresh air doors on the heater case to keep debris/sanding dust out of the HVAC system while working in the area.


Looks great and seems like a very simple process to get installed.

No Texas sun + garaged, I guess?

I did have to replace the cowl on my e39 at one point.

Good tip on the heater case-- will add that to the instructions.

[Bry5on]

Nice write up! Step 5d should also include installing the cabin filter housing as it goes in before the bracket to mount fasteners. In your version with the two holes in the cabin filter housing, you can tighten the bracket to brace last which is super nice.

For degreaser, I used acetone followed by IPA on the metal, always wiping in one direction with clean towels! For carbon, I did a very light abrade then a wipe with IPA.

I’d also recommend wetting out the surface of the bracket and where it mounts with a thin coat of epoxy. This will help guarantee a good adhesive bond. Then run your fingers around the squeeze out to create a nice fillet. You’ll have a bit messy of an install since access is tight, but this should ensure you get a good bond. I took pics of this, you can see it’s a little messy.

Some photos during install of you’d like to include them, I’ve got photos for most of your notes:

[Obioban]

Nice write up! Step 5d should also include installing the cabin filter housing as it goes in before the bracket to mount fasteners. In your version with the two holes in the cabin filter housing, you can tighten the bracket to brace last which is super nice.

For degreaser, I used acetone followed by IPA on the metal, always wiping in one direction with clean towels! For carbon, I did a very light abrade then a wipe with IPA.

I’d also recommend wetting out the surface of the bracket and where it mounts with a thin coat of epoxy. This will help guarantee a good adhesive bond. Then run your fingers around the squeeze out to create a nice fillet. You’ll have a bit messy of an install since access is tight, but this should ensure you get a good bond. I took pics of this, you can see it’s a little messy.

Some photos during install of you’d like to include them, I’ve got photos for most of your notes:

Incorporated some of your pictures, where mine were lacking!

I made the instructions have the adapter bracket get bolted (and then bolts removed) before firewall plug to ensure that was properly aligned before going after the firewall plug alignment-- trying to limit it to one thing being aligned at a time.

Will add your epoxy application notes and a link to your pics.

Thanks!

[Casa de Mesa]

You should add this to the official DIY thread!

[Obioban]

You should add this to the official DIY thread!

Good call, will do.