SLON-WORKSHOP Torsional Rigidity Platform. E46 M3 new experience & tests. Tech info

[Slonik]

So factory M3 has 18,500 nm/°
With $1,400 carbon fiber panel glued in along with solid aluminum bushings you measured 18,660 nm/°.
Got it. 😉

You are damn right - factory new M3 chassis had 18500 Nm/deg on papers.
And typically used e46 M3 chassis (about 100k miles), which had shown with all factory stiffening parts 14200Nm/deg on our stand before upgrades, had shown 18660Nm/deg with installed bushings and carbon wall.

But anyway, I respect Your pretending ability.

[old///MFanatic]

You are damn right - factory new M3 chassis had 18500 Nm/deg on papers.
And typically used e46 M3 chassis (about 100k miles), which had shown with all factory stiffening parts 14200Nm/deg on our stand before upgrades, had shown 18660Nm/deg with installed bushings and carbon wall.
But anyway, I respect Your pretending ability.

So 14,600 vs 18,660 (both using solid bushings) for that panel on an unassembled chassis.
I see now that’s ~28%.
Wasn’t this promoted at 39%?
*post edit

[heinzboehmer]

(18660 - 14600) / 14600 = 0.278

[old///MFanatic]

(18660 - 14600) / 14600 = 0.278

Ugh, that’s what I get for being lazy at 1AM at night asking Siri to give me a percentage calculator website.
https://www.omnicalculator.com/math/...age-difference

*will edit and fix post

[EthanolTurbo]

Does anyone know if Vincebar etc increases chassis stiffness?

[Slonik]

So 14,600 vs 18,660 (both using solid bushings) is 24.41% for that panel on a fatigued chassis.
Where you getting 28%?
24.41% vs a promoted 39% is off by a difference of 46% right?

Man, now i really don't understand what are you talking about.

We have promised 25%, that was my expectations:
https://www.instagram.com/p/CEL9u5jo...dium=copy_link

And, after those, i'd say that was even little bit pessimistic.

Where you get 24.41% i don't know, and what the rocket since in your way to calculate percentage increase.

I was studied in school that if i have 14600Nm/deg and we take it as 100%, so 18660Nm/deg 28% more. I hope i don't need to say, how to round figures and how i get 28% from 27.8%?

Ouch, by the way, you need to be better in googling- is that calc you have used?

https://www.omnicalculator.com/math/percentage-increase

it gives correct 27.8%

[Slonik]

Does anyone know if Vincebar etc increases chassis stiffness?

Chassis stiffness - i think yes.
Torsional rigidity - i think about 0.

Torsional rigidity works little bit different. I can make another post later, with some figures and try to explain how it works and why one things (even very rigid), make no difference, and other simple things could give you a HUGE difference.

[bigjae46]

Question...can you bond the panel to a painted surface or does it need to be bare metal?

[Slonik]

Question...can you bond the panel to a painted surface or does it need to be bare metal?

okay , glueing preparation FAQ
bonding quality = how much grip on your glued surface. so, you need to sand it good enough (as i said previously, we are recommending 240-320 grit).

during our work we are always worrying about corrosion in the future, so our guys always trying not to go till bare metal. from our experience glueing works excellent if you sand it to the factory primer (gray color under your paint layer) /sand deep enough factory paint layer, about a half for example - i know that without some good experience hard enough to understand how much is it, so easier marker - factory gray primer.
in that case you can get bonding force enough, to get carbon fiber destruction between layers before glue separates from the chassis.

attention! - if you made respraying previously, you can not trust to its grip, and again, you need to sand it till the factory primer.
and back to our situation - some people could have changed rear floor already. so in that case you also need to go to the factory primer. if, this surface on the bottom side was cleaned till bare metal during those work previously, so you have no factory primer, i'd recommend not to trust aftermarket respraying and go to the bare metal.
you can make test fitment of the wall and use marker to mark hidden zone, which will covered with the glue. then you can clean this surface only, so epoxy glue will cover it totally and you will get excellent rust protection.

we have made a lot of different tests (and a LOT more real world works) with glueing carbon vs metal, so i wrote this text with an experience from our practice.
long time before first wall was glued (it was 3 years ago), we've glued many rear side panels and carbon roofs .

[bigjae46]

okay , glueing preparation FAQ
bonding quality = how much grip on your glued surface. so, you need to sand it good enough (as i said previously, we are recommending 240-320 grit).

during our work we are always worrying about corrosion in the future, so our guys always trying not to go till bare metal. from our experience glueing works excellent if you sand it to the factory primer (gray color under your paint layer) /sand deep enough factory paint layer, about a half for example - i know that without some good experience hard enough to understand how much is it, so easier marker - factory gray primer.
in that case you can get bonding force enough, to get carbon fiber destruction between layers before glue separates from the chassis.

attention! - if you made respraying previously, you can not trust to its grip, and again, you need to sand it till the factory primer.
and back to our situation - some people could have changed rear floor already. so in that case you also need to go to the factory primer. if, this surface on the bottom side was cleaned till bare metal during those work previously, so you have no factory primer, i'd recommend not to trust aftermarket respraying and go to the bare metal.
you can make test fitment of the wall and use marker to mark hidden zone, which will covered with the glue. then you can clean this surface only, so epoxy glue will cover it totally and you will get excellent rust protection.

we have made a lot of different tests (and a LOT more real world works) with glueing carbon vs metal, so i wrote this text with an experience from our practice.
long time before first wall was glued (it was 3 years ago), we've glued many rear side panels and carbon roofs .

Thanks for the info.

Is galvanic corrosion an issue with steel?

Or…would corrosion be prevented if the adhesive is applied uniformly so that no carbon comes into contact with the steel.


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[Slonik]

Thanks for the info.

Is galvanic corrosion an issue with steel?

Or…would corrosion be prevented if the adhesive is applied uniformly so that no carbon comes into contact with the steel.


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theoretically more issues with aluminum, but even on that it works good enough with an epoxy based glue. so glueing to the steel surface wouldn't be an issue.
we have some factory bmw motorsport parts on hands, where they use bare aluminum with carbon. they are not even worried about it.

but anyway, we prefer not to forget about this effects during work and not to make clean contacts between carbon fiber and metal.

[bigjae46]

theoretically more issues with aluminum, but even on that it works good enough with an epoxy based glue. so glueing to the steel surface wouldn't be an issue.
we have some factory bmw motorsport parts on hands, where they use bare aluminum with carbon. they are not even worried about it.

but anyway, we prefer not to forget about this effects during work and not to make clean contacts between carbon fiber and metal.

Got it. I’d guess the galvanic corrosion issue is more of an aviation issue. How long is a Motorsport part going to last?


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[Slonik]

Got it. I’d guess the galvanic corrosion issue is more of an aviation issue. How long is a Motorsport part going to last?


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yeah, also have same thoughts. but anyway, looking on the price of this parts, i would like to get not only top engineered, but also more "long lasting" products

[old///MFanatic]

Man, now i really don't understand what are you talking about.
We have promised 25%, that was my expectations:
https://www.instagram.com/p/CEL9u5jo...dium=copy_link
And, after those, i'd say that was even little bit pessimistic.
Ouch, by the way, you need to be better in googling- is that calc you have used?

Yes I should have just found a pencil & paper then used calculator at 1AM. Big fail on my part not catching the incorrect settings for that online percentage website. Corrections made. Completely understand that confusion on my part.
As for the GB “promoted” 39% it was throughout thread starting as early as post #2, #4, #6, etc. That’s where I got it from. With never a correction made by you that I know of in thread.

https://nam3forum.com/forums/forum/main-forum/e46-2001-2006/group-buys-aa/82417-group-buy-for-slonik-cf-rear-bulkhead-which-can-optionally-be-a-back-seat-delete?p=82436#post82436

https://nam3forum.com/forums/forum/main-forum/e46-2001-2006/group-buys-aa/82417-group-buy-for-slonik-cf-rear-bulkhead-which-can-optionally-be-a-back-seat-delete?p=82421#post82421

https://nam3forum.com/forums/forum/main-forum/e46-2001-2006/group-buys-aa/82417-group-buy-for-slonik-cf-rear-bulkhead-which-can-optionally-be-a-back-seat-delete?p=82428#post82428

[Obioban]

Yes I should have just found a pencil & paper then used calculator at 1AM. Big fail on my part not catching the incorrect settings for that online percentage website. Corrections made. Completely understand that confusion on my part.
As for the GB “promoted” 39% it was throughout thread starting as early as post #2, #4, #6, etc. That’s where I got it from. With never a correction made by you that I know of in thread.
https://nam3forum.com/forums/forum/m...2436#post82436
https://nam3forum.com/forums/forum/m...2421#post82421
https://nam3forum.com/forums/forum/m...2428#post82428

I had never spoken to Slonik before I made the thread linking to the M3post GB. The numbers in that thread were from me-- not him. The only thing I've seen him post was an estimate of 25%. 28% surpassed his number. Further, you are being a bit selective if your post choosing. As in, in this post, I suggested that perhaps the plate added 5000nm/deg regardless of the starting point (which ended up being pretty close to the reality).
(for those that don't want to go read the thread, the most relevant data point were the e46 sedan, with and without fold through seats, at 13000 nm/deg and 18000 nm/deg respectively. That meant that the stock, metal rear wall was either good for 39% improvement or 5000 nm/deg. Now that we have measurements, it would seem that it's good for ~5000nm/deg. Before it was on the chassis twister, that was a question)

Not sure why you're trying to pick a fight here. There's tons of chassis stiffeners that are completely untested (e.g. Mason bar, every strut tower brace, etc). This is a new and innovative product that is making a massive difference in chassis stiffness for a reasonable price, likely with more new, similarly innovative products to come. To validate the products, he bought a freaking chassis twister! Nobody does this kind of R&D in aftermarket parts! That's great not only for new part development, but for knowing what actually matters vs doesn't.

Shooting all of us in the foot trying to derail this.