[Steve_Jr]

Here is the final stage : installing diagonal strut and stiffening plate. These parts were used for reinforcement of 4 series convertible body stiffness. When you can see 4 series convertible, there are 1 more V shape strut in front of intercooler intake. This V shape strut bridged to bottom torsion strut by stiffening plate. Total cost is $150.

It's not difficult work but just removing your front bumper and screw it. After installing this parts, drove a little ... It's like a E90 3 series body feeling. If you ever feel the car is not unstable, even when you drive strait on common express way, this work definitely can help the situation. So, All of previous struts seems to be properly worked with these parts. It's the last puzzle piece for E90 body feeling !!

[dotjonnL]

Wonder if this will work on the sedan and xDrives...

Does the bottom of our cars come with the aluminum diagonal pieces behind the new brace? And does the plastic belly pan cover all this? I haven't had the chance to peak under my car yet.

[Lancelot]

Thanks Steve_Jr!

Will try to do this next week as we have a slot in the workshop to install the LSD and rear stiffening plate, if we can get the parts by then.

We skipped the two pairs of strengthening rods (extension struts tower + links), not being convinced of the benefit if these can't be screwed on to he body.

[Lancelot]

http://www.realoem.com/bmw/enUS/show...diagId=51_8381

These are parts 18 "Structural reinforcement panel" (F33 only), 16 "Torsion bar, front" (F32 F33 only)
So for Sedans you need a pair of "Torsion bar, front" 18 too, coupés only need the reinforcement panel.

http://www.realoem.com/bmw/enUS/show...diagId=51_8380
black V is part 16 "Diagonal brace, lower" here (ref 51647294929) + 17 "adapter plate" that are specific to convertibles.

[dotjonnL]

Hmm I tried looking for it on the F33 435iX and it doesn't show up but for the non-xDrive it does.

I'm gonna assume the reinforcement plate will not work with xDrive models?

Did some more digging, the part is available for the F23 M240iX, do you guys think it'll work on F3x?

[Lancelot]

Hard to say, but if compatible with M240iX you've got a good chance it works on your 435iX too; a visual inspection is necessary though to confirm.

[Steve_Jr]

Hey Lancelot

I found bracket strut bridged into A-pillar ... It must be welded .. Any idea ?

Parts no.6 below page :

http://www.etkbmw.com/bmw/KO/search/...CE/41/41_2251/

Originally Posted by Lancelot

Hard to say, but if compatible with M240iX you've got a good chance it works on your 435iX too; a visual inspection is necessary though to confirm.

[Lancelot]

Yea i think you're right; but is it worth it? Difficult to know.

[Steve_Jr]

Today I ordered parts no.6 : A pillar bracket .. Let see ...

http://www.etkbmw.com/bmw/KO/search/...CE/41/41_2251/

Originally Posted by Lancelot

Yea i think you're right; but is it worth it? Difficult to know.

[Dr Thrillride]

Originally Posted by Steve_Jr

Hey Lancelot

I found bracket strut bridged into A-pillar ... It must be welded .. Any idea ?

Parts no.6 below page :

http://www.etkbmw.com/bmw/KO/search/...CE/41/41_2251/

Steve, how do you know it must be welded? It may just serve as a fitted bracket to secure the rod with a nut...let's hope so...if it's just spot welded on, which it can only be unless loose, then no biggie not to weld it. The issue will be access to the underside of that area. I'm going to take that grit panel off and look in there

[Lancelot]

If it's not welded it would be good news; and it's not bolted, we have no corresponding holes in the area afaik.

But if neither welded nor bolted, where would be the strengthening effect?

[Dr Thrillride]

Originally Posted by Lancelot

If it's not welded it would be good news; and it's not bolted, we have no corresponding holes in the area afaik.

But if neither welded nor bolted, where would be the strengthening effect?

Sitting it as is, is absolutely useless. I guess we wait to see what Steve says when he receives the part.

[Steve_Jr]

Bcz there's a plenty of gap between the edge of strut and A-pillar. Now only rubber bushing bridged these two, so even no bolting this part on A-pillar, it looks effective to be strengthen up.

Originally Posted by Lancelot

If it's not welded it would be good news; and it's not bolted, we have no corresponding holes in the area afaik.

But if neither welded nor bolted, where would be the strengthening effect?

[Steve_Jr]

Let's see the part first when it arrived ^^

Originally Posted by Dr Thrillride

Steve, how do you know it must be welded? It may just serve as a fitted bracket to secure the rod with a nut...let's hope so...if it's just spot welded on, which it can only be unless loose, then no biggie not to weld it. The issue will be access to the underside of that area. I'm going to take that grit panel off and look in there

[Lancelot]

Originally Posted by Steve_Jr

Let's see the part first when it arrived ^^

Thanks for leading the way on this excellent upgrade.

Together with this other thread on the rear axle we have superb solutions
http://f30.bimmerpost.com/forums/sho....php?t=1080995

[Steve_Jr]

You know what .. I already tried to install this kind of stuff ... with genuine M4 parts only $20. But now this were removed.

In a case of 4 series coupe which has V style tension strut (33316797444) Additional stuff seems useless or even weaken its stiffness. Bcz

1. without this stuff (CPM or Genuine M4's one) , tension strength can be effectively, directly diffused through : each bridge -> core of V tension strut -> body itself

2. with this stuff (CPM or Genuine M4's one) , tension strength can be indirectly diffused through : each bridge -> core of V tension strut -> CPM or Genuine M4's one -> body.

this means CPM or Genuine M4's one affected opposite direction. It worked like buffer or cushion ...

Originally Posted by Lancelot

Thanks for leading the way on this excellent upgrade.

Together with this other thread on the rear axle we have superb solutions
http://f30.bimmerpost.com/forums/sho....php?t=1080995

[Lancelot]

Just fitted the f80 underbody brace, f30 sedan doesn't have the V struts - to be added next time.

[Dr Thrillride]

Originally Posted by Steve_Jr

Bcz there's a plenty of gap between the edge of strut and A-pillar. Now only rubber bushing bridged these two, so even no bolting this part on A-pillar, it looks effective to be strengthen up.

How can it be effective to 'strengthen up' if it is not bolted to the frame? Sorry, it's just not clear

[Steve_Jr]

Originally Posted by Dr Thrillride

How can it be effective to 'strengthen up' if it is not bolted to the frame? Sorry, it's just not clear

In a case of a rubber bushing (current) replaced by a steel bracket, strength usually diffuse from strut to frame, it can be effective to strengthen up.

[cesare87]

Long shot but does anyone know if it would be possible to fit just the alloy brace without changing the suspension guide supports? Even if a little bit of modification is needed on the alloy strut itself.

Anyone?

[Lancelot]

Originally Posted by cesare87

Long shot but does anyone know if it would be possible to fit just the alloy brace without changing the suspension guide supports? Even if a little bit of modification is needed on the alloy strut itself.

Anyone?

As you can see from Steve's photos at the beginning, the F80 bearings have additional holes to bolt the alloy strut brace; so you would need to drill bolt threads in your F3x bearing.

But please, don't - this bearing bears 25% of your car weight on its own, weakening it is looking for trouble. Dangerous trouble.

[Dr Thrillride]

Originally Posted by Steve_Jr

In a case of a rubber bushing (current) replaced by a steel bracket, strength usually diffuse from strut to frame, it can be effective to strengthen up.

Not a chance of any strengthening with that configuration Steve, but at least the rods are in place while something else Is figured out.