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

[heinzboehmer]

To validate the products, he bought a freaking chassis twister!

It looks like they built their own, which is even cooler

[Slonik]

It looks like they built their own, which is even cooler

before building it, i've searched for any info in web. all what i've found - two examples from students projects. one with "formula student" (its a small race car, closer to the carting), and another one, where they made some measument system and had tested hatchback.

any garage tryings - i wouldn't count, cause accuracy in that case like "20k Nm better than 10k Nm".

so, we've drawn our own platform, rigid enough for compfortable work without fixing to the floor (to get some mobility), and then i've choosed and purchase measurement items.

and yeah, all this stuff we designed and made ourself in our workshop.
platform - it was a LOT of square tubes at the begin, and than many weeks of welding.
all this bars, aluminum adapters etc, all of that were made here in-house.

[usdmej]

thank you Slonik for joining the forum! it's always nice to see vendors communicate directly with consumers

is there any possibility of creating the bulkhead with cutouts to allow items like skis to pass through the trunk?
some of us here wouldn't mind losing some stiffness to keep some functionality

[Slonik]

thank you Slonik for joining the forum! it's always nice to see vendors communicate directly with consumers

is there any possibility of creating the bulkhead with cutouts to allow items like skis to pass through the trunk?
some of us here wouldn't mind losing some stiffness to keep some functionality

Depends on demand. till this moment, you are the first, who ask about this ski cut out
main issue to make comparable level wall, and have that center cutout, we need to make additional stiffness around it many times more.

i'd say it will cost a lot more due to this "simple" cutout.
all of that applicable, if we speak honestly only.
however, if we mount this wall like some "nice view thing", and about none from performance side - that's simple, and "lets make it"

but, really. my automotive religion doesn't allow me to make this bullshit ahahaha

[ridebikes]

Very cool product, and 100% agree that it's great to see new, top flight vendors building for our cars 👍

My question is how this product might interact with an X-brace style bar (like the type made by Mason, CMP, etc.) that connect the shock towers? I'm not an expert but it seems conceptually similar (though it's strengthening a different part of the car, of course). Would there be benefit to running both? Anything to keep in mind?

Thank you!

[terra]

Depends on demand. till this moment, you are the first, who ask about this ski cut out
main issue to make comparable level wall, and have that center cutout, we need to make additional stiffness around it many times more.

i'd say it will cost a lot more due to this "simple" cutout.
all of that applicable, if we speak honestly only.
however, if we mount this wall like some "nice view thing", and about none from performance side - that's simple, and "lets make it"

but, really. my automotive religion doesn't allow me to make this bullshit ahahaha

A few of us had asked about a cutout in the group buy thread, but that might have gotten missed. I do have this wall sitting in my garage, but if something could be made compatible with the ski pass through, I’d be very interested in that.

[Tbonem3]

but, really. my automotive religion doesn't allow me to make this bullshit ahahaha

[oceansize]

Sounds like Khabib Nurmagomedov (MMA and possible GOAT from Dagestan), #1 bullshit... LoL.

[jet_dogg]

Lmao such a great quote.

[tnord]

Okay i'll go forward.

Some useful specs for the begin:
BMW E46 Sedan (w/o folding seats) - 18,000 Nm/deg
BMW E46 Sedan (w/folding seats) - 13,000 Nm/deg
BMW E46 Wagon (w/folding seats) - 14,000 Nm/deg
BMW E46 Coupe (w/folding seats) - 12,500 Nm/deg
E46 M3: 18,500 nm/deg
E46 M3 CSL: 18.750 nm/deg


But anyway, this figure was far away, from i expected to see. Okay, i've made some discount, cause its very close to E46 coupe (non M) chassis, so maybe all other screwed stuff will make this difference.
Aaaand we've continued to fit different oem parts, like doors (about nothing by the way), front end panel + bumper support brace (+400nm), rear backs of the seats (nope ), and even under dash brace (also nope )
Anyway, during fitment all this parts, step by step, sometime in 200nm, sometime in 300-400nm, we have gone to 14200 Nm/deg. That was final stock torsional rigidity. That's... sad i think

On another side, what i want to expect from old used chassis with long story etc.
So, that's about 23 percent of losses from factory figures (on paper?).

I asked the question here, or to somebody else, about getting the chassis seam welded at one point. Whoever I asked questioned if it was really that much of a benefit. Would this be evidence of spot welding loosening or giving up over time? Or what would this weakening be from?

[Epoustouflant]

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.

The numbers you posted were from my original M3post thread - which were numbers Slon had given and were provided in his original technical documentation.

See attached.

[bigjae46]

If I remember correctly from when Paffy was building his roll cafe on the old M3Forum. He tied in the rear subframe mounts into the cage. He took a video of how much the front mounting points were moving and it was A LOT! Not sure if he had cut the rear deck out at that point.

That drove my decision to tie all 4 subframe mounts together and then tie them into the roll cage in 4 places.

I’m fairly confident that these panels will add a lot of stiffness.

Question…I know that my car is far stiffer since I put the cage in. I can lift both tires on one side with just a couple of pumps with the floor jack. Before the cage, I had to use my heavy duty jack and lift it pretty high to get both wheels off the ground. Would this be a quick way to provide that the panel adds stiffness?


Sent from my iPhone using Tapatalk

[old///MFanatic]

I asked the question here, or to somebody else, about getting the chassis seam welded at one point. Whoever I asked questioned if it was really that much of a benefit. Would this be evidence of spot welding loosening or giving up over time? Or what would this weakening be from?

Well I think we can agree it’s very early in testing on one shell to surmise our E46 M3 are experiencing as great as 24% loss in structural rigidity. Losses are common though! BMW ///M states using an additional 102 (or 120?) welds on the M3 over non-M coupe to improve chassis. As for additional seam welds, yes that’s a common practice in prepping a race frame. While working for Gurney’s race team long ago we’d see gains when tested on our in house R&D structural rigidity rig.
I would go and put my M3 on rig for base numbers but don’t know anyone there anymore. The facility does more aerospace now. My buddy who was our CF composites guy might.

[Slonik]

Very cool product, and 100% agree that it's great to see new, top flight vendors building for our cars 👍

My question is how this product might interact with an X-brace style bar (like the type made by Mason, CMP, etc.) that connect the shock towers? I'm not an expert but it seems conceptually similar (though it's strengthening a different part of the car, of course). Would there be benefit to running both? Anything to keep in mind?

Thank you!

Like you noticed correct, we are strengthening different parts of the chassis - they are close enough, but still different.

i'd prefer to separate different advantages and goals.
it doesn't mean, that each product gives you only the one goal, but, surely, each product have own strengths - what it gives mainly.
of course, some of the products will gives you some other benefits besides of main, but with the less effect.


in what exactly those x-braces unequivocally will work better (and i think its the main target) - our E46 cracking overloaded floor strengthening. they are stiffening rear mounting points of the subframe.
is it the best way to strength them? it's effective enough, but i don't think that this is the best (i can explain my thoughts, if you want. but it's a large topic ).
does those style x-brace make difference in the torsional rigidity? i think also yes, but this benefit goes more like additional, and i would guess, that it will gives about 5% (maximum 10%, if you use solid bushings on the subframe).

same time, our wall do about nothing with the rear mounting points of the subframe.

[IamFODI]

Is it possible that something about the rig is producing a lower number than what BMW’s rig would show? Kind of like different dynos producing different numbers for the same engine?