GB for SLON Workshop CF Rear bulkhead, which can (optionally) be a back seat delete

[Obioban]

Group buy link: https://docs.google.com/forms/d/e/1F...Jxrsg/viewform



So, some chassis stiffness context. The e46 sedan was offered with or without fold through seats. If you didn't get fold through seats, there was a metal bulkhead in the same location as this panel. Chassis stiffnesses were as follows::
E46 Sedan (w/o folding seats) 18000 nm/deg
E46 Sedan (w folding seats) 13000 nm/deg

So, at least for the e46 sedan, the car was 38% stiffer without fold through seats.

Also of note:
E46 M3: 18500 nm/deg
E46 M3 CSL: 18750 nm/deg

There only cause of the difference in chassis stiffness between the M3 and CSL is the CF roof on the CSL. So, a tiny bit of bonus for this being CF.


Slonik, who has an excellent reputation in the e9X M3 community, is making a rear bulkhead for the e46 M3. This can be run with the back seats installed, if you have back seat passengers, or as a back seat delete.

Some pictures installed in the e46 M3:





Forum moderator SYT Shadow posted a DIY guide to installing this (in an e90 M3, but the process would be identical) here:
https://nam3forum.com/forums/forum/e...orcement-panel


Group buy link here: https://docs.google.com/forms/d/e/1F...Jxrsg/viewform

The group buy is for e9X and e46 panels. It is currently at 14 participants. Pricing is as follows:
5-9 pcs: $1,700
10-19 pcs: $1,550
20 + pcs: $1,450

Group buy closes friday, price includes shipping.

And, because I know I'd ask, these are made in Russia (also known as not China).

I'm on the list. Let's get to 20!

Edit: I’m not the organizer of this gb, just a participant. This was organized over on M3post— it just also applies to us, since there’s an e46 part included in the gb.

[SYT_Shadow]

This is the closest you'll see to OEM quality. It is a beautiful piece!

Some more info:
E46 Sedan (w/o folding seats) 18000
E46 Sedan (w folding seats) 13000
E46 Touring (w folding seats) 14000
E46 Coupe (w folding seats) 12500
E46 Cabrio 10500
What do we need to see here? Comparing two sedans' torsional rigidity – the difference between two chassis is limited to the steel wall behind the rear seats! 38% increase of torsional rigidity with only one chassis element difference!
Another interesting fact is that e46 coupes and even e46 m3s don’t have chassis options without folding seats (with the factory wall). Same for the next generation e9x chassis – bmw didn’t offer “w/o folding seats” option at all, so all versions have a hole instead of a wall.

[heinzboehmer]

What's the deadline for this? I'm seriously considering one, but need to decide if I'm ready to give up the extra trunk space you get with the seats down.

[Obioban]

To anyone wondering, can you feel a 38-39% chassis stiffness increase? The answer is 100% absolutely yes. I simultaneously owned 2 e39s, with and without fold through seats, and could easily tell which was which from behind the wheel.

[Drlph25]

Very cool piece, excited for this. I'm on the list for 2(e46/e92)..will be replacing my home made rear seat delete panel!

[Obioban]

39% increase in chassis stiffness for $1400 has to be one of the best performance/$ increases available for the car!

[Tonggi]

What's the deadline for this? I'm seriously considering one, but need to decide if I'm ready to give up the extra trunk space you get with the seats down.

Also curious with this. I would like to get one. (maybe 2 if i buy the toy) I will add my nametot the list

[SYT_Shadow]

Updates

This price includes shipping

The GB closes this Friday

[Icecream]

39% increase in chassis stiffness for $1400 has to be one of the best performance/$ increases available for the car!

If it actually gives nearly 40% additional stiffness, this would be the best modification hands down. Too bad getting actual data on this would be difficult. Excited to hear what more people think after installing!

[r4dr]

If it actually gives nearly 40% additional stiffness, this would be the best modification hands down. Too bad getting actual data on this would be difficult. Excited to hear what more people think after installing!

There's an install thread in the E9X forums on here for the equivalent product. Looks like a nice piece.

[Epsilon]

Would installing a tie bar or x-brace in the rear provided similar rigidity?

[Good]

A few questions: Does this piece not require the rear folding seats? How is this mounted? And lastly is it possible to get without the huge M logo in the center?\

Edit: I see this is to be glued into place

[Obioban]

Would installing a tie bar or x-brace in the rear provided similar rigidity?

Unlikely

A few questions: Does not require the rear folding seats? How is this mounted? And lastly is it possible to get without the huge M logo in the center?\

Edit: I see this is to be glued into place

Yeah, if you want the chassis stiffness benefit, you need to glue it into place (I'll be using the same glue as used on the CF roof). You could screw/rivet it in if you didn't care about the extra stiffness and wanted to weight save the back seat, but for sure you won't get anything like the stiffness increase (if any).

I doubt the M logo is removable, as CF parts are molded-- not easy to change a mold.

Not sure what you were asking when you said, "Does not require the rear folding seats?", but you can remove the back seats if desired. Or not, if you don't.

... or get crafty and adhere the seats directly, negating the need for the metal back panel on them or the fold through release mechanism. I don't know how feasible that will be, but I'm absolutely going to look into it.

[Good]

Unlikely



Yeah, if you want the chassis stiffness benefit, you need to glue it into place (I'll be using the same glue as used on the CF roof). You could screw/rivet it in if you didn't care about the extra stiffness and wanted to weight save the back seat, but for sure you won't get anything like the stiffness increase (if any).

I doubt the M logo is removable, as CF parts are molded-- not easy to change a mold.

Not sure what you were asking when you said, "Does not require the rear folding seats?", but you can remove the back seats if desired. Or not, if you don't.

... or get crafty and adhere the seats directly, negating the need for the metal back panel on them or the fold through release mechanism. I don't know how feasible that will be, but I'm absolutely going to look into it.

I see. I try not to run those rear foldable seats and currently have a street faction rear seat delete that I am returning for the aluminum fixed back version, however this does have me interested.

[Obioban]

I see. I try not to run those rear foldable seats and currently have a street faction rear seat delete that I am returning for the aluminum fixed back version, however this does have me interested.

No pressure, but 2 days to decide :P
(well, for GB pricing anyway)