[F87source]

Originally Posted by M Fifty

Good picture. This is what I meant when I said that the unsupported length of the BMW CF brace was clearly not a problem given that in front end impacts it was the bracket that failed first. So it's pretty good in compression as well as tension.

You still don't understand the difference between rigidity and tensile strength. The brace clearly has massive tensile strength to the point where the bracket fails first, however that doesn't address anything about rigidity or the ability to transfer it.


The longer the lever arm the more susceptible it is to flex, hence why a long piece of wood will bow in the middle vs. a shorter piece of wood which will not bow. Bolting down the brace in multiple places shortens the lever arm reducing any mechanical advantage reducing flex and increasing its ability to transfer forces to the brace making it more rigid. This is basic physics....

Originally Posted by M Fifty

Yep those are where the BMW Aluminium brace attaches to - and the CF part bolts to it. My point was that the Turner Braces don't. HTH?

The turner brace does bolt to the strut tower, take a look at the bracket where the stock brace bolts to. It's welded to the tower...

Originally Posted by M Fifty

Also bollocks.

Your favoured product needs to mount in exactly the same way as the M4 brace for this to be even remotely true, plus when was the last time you flew on a steel aircraft? To match the stiffness, the steel item will end up heavier.

Maybe if you clarify what you mean by wheelhouse? The M2 isn't a ship, so doesn't have a rudder...

1) You don't understand the direction of movement of the strut tower do you? When the tower moves towards each other or away from each other the best bracing position is between the towers, that offers the best way to transfer forces. The m4 aluminium brace is angled and cambered so all the force are now acting on an angle to the brace in a direction where there is less material reinforcing it making it weaker - this being the joint.

A stronger material doesn't necessarily brace better than a weaker material if it takes the forces in the wrong direction. The stock aluminium m4 brace has to take forces for every direction, and its design isn't strong in every direction. If the strut towers are moving up or down all the forces go to the joint which isn't reinforced well.


You also need to remember a tubular item is stronger in design because it can take forces in all directions, whereas a flat piece is stronger in the axis of its thickness. So in some directions the m4 brace is strong in some directions it is weak, a tubular piece is stronger in more directions.


2)

a) Youngs modulus, which is taken into account by cross sectional area (so size) per unit area steel is far more rigid than aluminium: https://www.thefabricator.com/thefab...0of%20aluminum.


b) Yes you get a weight penalty but the rigidity is 3x higher, so depending on aluminium grade the strength to weight ratio vs. a steel grade may not make up for it.


Also density is a contributing factor. Aluminium has a lower density than steel, so a same size object is lighter but not stronger. For example an m8 aluminium bolt is the same size as a grade 12.9 steel bolt, it is lighter than the steel bolt but it is many factors weaker. When braces are made size is taken into account too, so for the same size piece steel is stronger despite a weight penalty.

Why do you think critical components are not all aluminium? Roll cages, crank shafts, rods, etc. Because to make aluminium as strong it has to be too big. Even steel wheel bolts are better than titanium wheel bolts, because for the same size titanium isn't strong enough.


Planes are aluminium because the strength to weight ratio is strong enough to satisfy the fuslage requirements. But take a look the landing gear isn't aluminium. Ships aren't aluminium, because it would take really thick sheets of aluminium to meet the strength requirements.


Weight isn't the only question, design matters too.


So in summary a similar size item steel is going to be heavier but it'll be stronger. The only way aluminum gets stronger is if it's the same weight but that means it'll have to be much bigger than the steel part. In terms of weight vs. strength of aluminum vs. steel it is so dependent on grade of either material and design. So its hard to say how much weight you'd be saving with aluminum to get a similar strength.

In a space sensitive area the weight trade off for a tubular steel part like the afe part would be worth it over aluminum because it'll be so much stronger.


Either way the stock part is the stock part, a pretty damn good design but I believe an aftermarket strut tower brace will easily outperform it. Especially the afe brace, that thing is a beast.



c) I explain explicitly what the wheel house is in my review.

Originally Posted by M Fifty

I'm aiming for where the goalposts appear to be in your posts?

You bring on new unrelated topics each time I answer.

Originally Posted by M Fifty

It certainly doesn't - as you say. Whether the aftermarket products highlighted here are more effective than the M235i Racing items reused on the F8X M3/M4 and M2C (as asserted by the OP) - rather than merely being cheaper - is my issue with the OP.

I also have doubts about the cost effectiveness of the aftermarket products highlighted here compared to the BMW items as they are bolted in locations that appear to offer less bang for the buck and major on the cosmetic aspects. If they attached to the strut towers using the mounting points for the strut tops and then tied in the mounting points for the corner braces, that would be a compelling alternative offering.

HTH

The corner braces are more for wheel house bracing, not solely strut tower. The carbon m4 brace doesn't even attach to the wheel house region so how can it even come close to providing more rigidity for this area. Add in a strut brace made specifically for the movement of the strut towers (in a material far superior than aluminium such as carbon) then it will out perform the bmw solution.

Originally Posted by M Fifty

Looking through RealOEM (which does have a number of errors), the earliest F8X (M3/4) came with a CFRP front brace with the part number 51618061631 (weighing 2.295 kg). This is listed as being used from 03/03/2014, which is inconsistent with the launch date of the various models. It is however listed as superseding 41008417085 (weighing 1.862 kg) but that is only listed for the M235i Racing from 11/01/2013.

This suggests that the brace predates the M3/4, even though the dates don't match.

So, there are now two scenarios:
1. BMW developed a chassis bracing system for motorsport use which they subsequently adapted for use on road cars for marketing reasons.
2. BMW developed a chassis bracing system as a marketing device, and subsequently used it for motorsport applications (but tried to make it even lighter and subsequently replaced it with a stronger item).

In the former case they will have prioritised effectiveness (so a trade off between weight and stiffness) while minimising cost. Using it on road cars was primarily a marketing solution (as said road cars would be unable to exploit the benefit), but it wasn't cost prohibitive and did actually work.

In the latter case, the marketing solution would have prioritised bling while minimising cost. While wishing to maximise the marketing potential, it would only ever have been used for motorsport if it provided a benefit that couldn't be realised more cheaply using other means.

In both cases, had just beefing up the corner braces yielded significant benefit, we could reasonably expect to see something like the Turner items on the M235i Racing (or just thicker versions of the wriggly tin items rendered in steel or aluminium), as there would be a compelling cost/benefit and weight reduction benefit compared to what they did come up with for marketing or motorsport use.

Having fitted the BMW supplied uprated parts on three cars now (R53, E46, F87), the difference can be felt in the steering while turning when going over camber changes and rumble strips at both low and high speeds. So, they are doing something.

If you can't feel any difference when using products from other suppliers, that doesn't mean they aren't making an improvement to your car's handing, but away from a track day with data-logging - how would you know?

But, they are significantly cheaper than BMW's solution, and - in concert with additional strut bracing - might result in a difference you can feel rather than only measure with data-logging on track.

HTH.

Parts availability is always lagging behind chassis availability. The m3/m4 was in production long before the m235ir (and thus designed even earlier), so clearly the parts came from the m3/m4...


The corner braces were only released with the cabriolet models and were designed to meet a budget target. Why would bmw spend even more making molds and tooling when they could reuse the f8x bits.


BTW as I said before as a total package the m4 brace offers better performance. It is only when you add strut tower bracing the corner braces become better, as it more effectively braces the wheel house.

[F87source]

Originally Posted by M Fifty

Seems fair. It is more cost effective. The problem was the assertion that it was better, rather than cheaper.

In terms of wheel house bracing yes, absolutely better. Forces aren't transferred wirelessly, so clearly the more bolting the better forces can be transferred.

Longer arms of action means more leveragee thus more flex as well. more bolting reduces that.


As an overall package, alone the corner braces will not reinforce the strut towers enough to do so. Add in specialty items that act in more favorable directions of strut tower movement then it will absolutely out perform the stock aluminium brace:

1) You have the corner braces for wheel house bracing, plus a connection to the strut tower. This means the wheel house is reinforced and the strut tower is tensioned from the from against moving up and down or foward and back.

2) You have the stock strut brace again tensioning the strut from moving forward and back and holding it down.

--- The m4 brace only secures the strut tower from the back side so if the towers move up it will put alot of force along the weakest joint of the brace again the point of attachment which has little material to support it as it is only a flat section of aluminium joining it.

3) Then you have a dedicated strut tower brace to deal with all the movements left and right, and it is directly in the path of the forces leading to the most efficent force transfer.


I've consistently said that.

[F87source]

It also looks like 2 of the side bolts holding down the corner braces don't have bolt holes on the m2 and require riv nuts. Yeah that's going to reduce alot of the strength.

[F87source]

While removing the aluminium brace here this mechanic losens all the strut bolts and leave the middle firewall bolts. He then tugs on the side of the brace and you can see there is alot of flex allowing it to lift. So if the bolts to the side of the strut tower bolts are not present on the m2 upward flex is going to be a problem. Again, a long unsupported arm is going to flex regardless of material, nothing is infinitely rigid.

This is why I think having multiple points of bracing is better, you have a short arm attaching straight to the strut tower via the corner brace, then the firewall brace is another - despite being longer like the m4 aluminum brace, then you have the strut tower brace on top. 3 Independt strut tower bracing items, vs. a 1 piece item.

[ZM2]

Let’s see…the simple fact that I have to spend money, labor, and alignment for new camber plates to retrofit the M3/4 setup, vs being able to easily install the Turner braces in my driveway in less than an hour with lower total labor & costs…easy decision.

[F87source]

Originally Posted by ZM2

Let’s see…the simple fact that I have to spend money, labor, and alignment for new camber plates to retrofit the M3/4 setup, vs being able to easily install the Turner braces in my driveway in less than an hour with lower total labor & costs…easy decision.

That's always an expensive factor yes. The other thing I don't like about the m4 setup is you may have to cut the fenders, and you'd likely have to add riv nuts to the chassis for extra bolts.

[M Fifty]

Originally Posted by ZM2

Let’s see…the simple fact that I have to spend money, labor, and alignment for new camber plates to retrofit the M3/4 setup, vs being able to easily install the Turner braces in my driveway in less than an hour with lower total labor & costs…easy decision.

Good.

[M Fifty]

Originally Posted by F87source

That's always an expensive factor yes. The other thing I don't like about the m4 setup is you may have to cut the fenders, and you'd likely have to add riv nuts to the chassis for extra bolts.

No to cutting the fenders. The holes are already there for the rivnuts, and BMW will sell you them. Setting them can be done with either a specialist tool, or a suitable sized bolt, a couple of nuts and a few washers.

But yes - it's a project to fit, and has an extensive (and expensive) parts list - further details can be found in one of the threads that cover the ins and outs of doing it. Broadly, you have to want to do it (or be prepared to pay someone else). Having done it, it was fun, and I like the result.

HTH.

[M Fifty]

Originally Posted by F87source

While removing the aluminium brace here this mechanic losens all the strut bolts and leave the middle firewall bolts. He then tugs on the side of the brace and you can see there is alot of flex allowing it to lift. So if the bolts to the side of the strut tower bolts are not present on the m2 upward flex is going to be a problem. Again, a long unsupported arm is going to flex regardless of material, nothing is infinitely rigid.

This is why I think having multiple points of bracing is better, you have a short arm attaching straight to the strut tower via the corner brace, then the firewall brace is another - despite being longer like the m4 aluminum brace, then you have the strut tower brace on top. 3 Independt strut tower bracing items, vs. a 1 piece item.

Okay, so noting the video shows an S55 car rather than an N55 car retrofitted with the brace, he has removed the centre bolts before he starts pulling on the rest of the brace - perhaps if you could give a timestamp for the bit you're looking at?

A one peice brace between the strut towers and the firewall, with as many different mounting points as the one in the video has, is going to be stiffer for the weight in all directions than two of the braces you mention above. The corner braces aren't there to brace the strut towers, but to help tie the structures in front of the strut towers and the bolt on centre section together. The BMW Boomerang does that by tying the (now reinforced) strut towers directly to the bolt in centre section.

Not sure if this is helping your understanding or not, but I'll keep trying.

[F87source]

Originally Posted by M Fifty

No to cutting the fenders. The holes are already there for the rivnuts, and BMW will sell you them. Setting them can be done with either a specialist tool, or a suitable sized bolt, a couple of nuts and a few washers.

But yes - it's a project to fit, and has an extensive (and expensive) parts list - further details can be found in one of the threads that cover the ins and outs of doing it. Broadly, you have to want to do it (or be prepared to pay someone else). Having done it, it was fun, and I like the result.

HTH.

That's what I'm worried about, the riv nuts, and yes I'm very familiar with them as I use aluminum ones for my front lip. Stainless has good strength, some don't, some have a low spin strength.

Originally Posted by M Fifty

Okay, so noting the video shows an S55 car rather than an N55 car retrofitted with the brace, he has removed the centre bolts before he starts pulling on the rest of the brace - perhaps if you could give a timestamp for the bit you're looking at?

A one peice brace between the strut towers and the firewall, with as many different mounting points as the one in the video has, is going to be stiffer for the weight in all directions than two of the braces you mention above. The corner braces aren't there to brace the strut towers, but to help tie the structures in front of the strut towers and the bolt on centre section together. The BMW Boomerang does that by tying the (now reinforced) strut towers directly to the bolt in centre section.

Not sure if this is helping your understanding or not, but I'll keep trying.

If you tie one structure to another you're bracing it whether you like it or not. The corner braces absolutely braces the strut tower by securing it with a rigid object to the front frame (wheel house), if the strut tower tries to move it has to move the brace which is fixed. Obviously it's not as efficient as a multi point attached brace (or a strut tower brace where the forces again are in the direction of bracing) as the strut tower can try to rotate around the sole mounting point, but it'll be brace forward and back were the force is in the direction of bracing.



Watch the engineering explained video I linked, he talks about strut tower movements.

[M Fifty]

Originally Posted by F87source

In terms of wheel house bracing yes, absolutely better. Forces aren't transferred wirelessly, so clearly the more bolting the better forces can be transferred.

Longer arms of action means more leveragee thus more flex as well. more bolting reduces that.


As an overall package, alone the corner braces will not reinforce the strut towers enough to do so. Add in specialty items that act in more favorable directions of strut tower movement then it will absolutely out perform the stock aluminium brace:

1) You have the corner braces for wheel house bracing, plus a connection to the strut tower. This means the wheel house is reinforced and the strut tower is tensioned from the from against moving up and down or foward and back.

2) You have the stock strut brace again tensioning the strut from moving forward and back and holding it down.

--- The m4 brace only secures the strut tower from the back side so if the towers move up it will put alot of force along the weakest joint of the brace again the point of attachment which has little material to support it as it is only a flat section of aluminium joining it.

3) Then you have a dedicated strut tower brace to deal with all the movements left and right, and it is directly in the path of the forces leading to the most efficent force transfer.


I've consistently said that.

The corner braces don't brace the strut towers though? They brace what's in front of the strut towers. The boomerang does that too - but is much more rigidly mounted (multiple fixing points to a now significantly stiffer strut towers assembly).

Perhaps if you try to explain point 2?

[M Fifty]

Originally Posted by PackPride85

The effectiveness of the aftermarket is close enough when you take cost/effort into consideration that I'd rather spend less of both taking all of 30 seconds to bolt in a strut tower bar and new corner braces over mess around with fitting the m4 setup.

If it makes a difference - it's definitely something to do. But, while easy to implement, if it made a worthwhile difference ///Marketing would be selling it (based on previous behaviour. Yes?

[M Fifty]

Originally Posted by F87source

It also looks like 2 of the side bolts holding down the corner braces don't have bolt holes on the m2 and require riv nuts. Yeah that's going to reduce alot of the strength.

These use the same fixings as your favourite product though - yes? So, what point are you trying to make here?

[M Fifty]

Originally Posted by F87source

In terms of wheel house bracing yes, absolutely better. Forces aren't transferred wirelessly, so clearly the more bolting the better forces can be transferred.

Longer arms of action means more leveragee thus more flex as well. more bolting reduces that.


As an overall package, alone the corner braces will not reinforce the strut towers enough to do so. Add in specialty items that act in more favorable directions of strut tower movement then it will absolutely out perform the stock aluminium brace: Now, we are getting somewhere

1) You have the corner braces for wheel house bracing, plus a connection to the strut tower. This means the wheel house is reinforced and the strut tower is tensioned from the from against moving up and down or foward and back.Maybe try explaining that again?

2) You have the stock strut brace again tensioning the strut from moving forward and back and holding it down.Based on the angles and construction, the stock strut brace is designed to reduce the movement of the strut towers relative to each other and the firewall (in both tension and compression). Holding it down - not so much.

--- The m4 brace only secures the strut tower from the back side so if the towers move up it will put alot of force along the weakest joint of the brace again the point of attachment which has little material to support it as it is only a flat section of aluminium joining it.No. It does what the stock brace does but much, much better. It also has multiple points of attachment. So, please try to explain your statement?

3) Then you have a dedicated strut tower brace to deal with all the movements left and right, and it is directly in the path of the forces leading to the most efficent force transfer.Yup. The stock brace, and - to an even greater extent - the M4 brace.


I've consistently said that.

Can you point me to the specific text? I've just gone through the entire thread - again - and while you may have been thinking it, it may have got lost in some of your other points.

[M Fifty]

Originally Posted by F87source

That's what I'm worried about, the riv nuts, and yes I'm very familiar with them as I use aluminum ones for my front lip. Stainless has good strength, some don't, some have a low spin strength.






If you tie one structure to another you're bracing it whether you like it or not. The corner braces absolutely braces the strut tower by securing it with a rigid object to the front frame (wheel house), if the strut tower tries to move it has to move the brace which is fixed. Obviously it's not as efficient as a multi point attached brace (or a strut tower brace where the forces again are in the direction of bracing) as the strut tower can try to rotate around the sole mounting point, but it'll be brace forward and back were the force is in the direction of bracing.



Watch the engineering explained video I linked, he talks about strut tower movements.

Okay, as mentioned above, I've been through the entire thread where you describe the Turner braces and A. N. OTHER strut brace as more effective than the item BMW came up with. It's okay, everyone has their own opinion. But, while your proposed solution is really, really much easier and less expensive to retrofit than BMWs solution, due to the way that the original bracing system, and the one its possible to retrofit from BMW work, to say that it's better (rather than cheaper and easier to retrofit) is my problem with what you've posted.

But in the interests of trying to understand your points outside of the above, could you point me to the post where you link to the engineering video? TIA.

[F87source]

Originally Posted by M Fifty

Okay, as mentioned above, I've been through the entire thread where you describe the Turner braces and A. N. OTHER strut brace as more effective than the item BMW came up with. It's okay, everyone has their own opinion. But, while your proposed solution is really, really much easier and less expensive to retrofit than BMWs solution, due to the way that the original bracing system, and the one its possible to retrofit from BMW work, to say that it's better (rather than cheaper and easier to retrofit) is my problem with what you've posted.

But in the interests of trying to understand your points outside of the above, could you point me to the post where you link to the engineering video? TIA.

It's in my original review unless it didn't embed.


I already explained to you about how the forces are transferred and how the corner braces increase the rigidity the wheel house better than the m4 carbon brace can, because you have to attach in multiple points to transfer forces effectively. I also explained despite the m4 brace showing immense tensile strength in a collision where the mounts break first, this is not a sign of high rigidity because tensile strength and rigidity are not the same thing. Example a string has little to no rigidity but massive tensile strength. The same applies here, the brace could have bent alot during the crash but tensile strength, yield strength, and shear strength prevented it from breaking. The install videos proved it can easily flex, so having just 2 mounting points do not make it effective in bracing the wheel house.


I already explained that the corner braces alone will not be as effective in bracing the strut towers as the m4 solution simply due to the presence of the aluminium firewall strut brace. However, I also explained based on the geometry and material construction of the aluminium brace, adding in an aftermarket strut tower brace in conjunction with the corner braces will absolutely create a better bracing package.

Why is this the case? Because the geometry for bracing will be better, the dedicated strut tower brace will resist the forces of the strut towers moving left and right way better because it is in the direction of the brace itself meaning it will only have to deal with tension and compression, whereas the m4 brace with its different geometery and camber on the strut mounts will have to deal with shear forces, bending forces, and torsional forces all on points of the brace with little material.


Then the corner braces + the stock tubular braces + the strut tower braces can deal with forward and aft movement all together helping distribute the load. Whereas the aluminium brace has to do it all alone.


Overall this is a circular argument polluting my thread, I have said what I need to say and that's the end of it on my end.

[M Fifty]

It didn't embed - but there were some interesting looking animations.

[jello]

Hi Op! I wanted to inquire if these Turner CF Brace would fit using a Dinan Intake (https://www.dinancars.com/products/i...arts/D760-0038)

As you know, when the Dinan Intake is installed using the stock corner braces, one of the braces will need to be cut and modified so that it could fit.

I read through your entire post and maybe i missed it but does the turner brace and stock brace show the same height clearance from the stock intake? If so, then there's no way to use the Dinan Intake then.

Any help would be highly appreciated from you or anyone. I want to pull the trigger and buy these but i don't know if it will fit the Dinan Intake.

For reference, here's a picture of the installed Dinan Intake with the modified stock brace:

[F87source]

Originally Posted by jello

Hi Op! I wanted to inquire if these Turner CF Brace would fit using a Dinan Intake (https://www.dinancars.com/products/i...arts/D760-0038)

As you know, when the Dinan Intake is installed using the stock corner braces, one of the braces will need to be cut and modified so that it could fit.

I read through your entire post and maybe i missed it but does the turner brace and stock brace show the same height clearance from the stock intake? If so, then there's no way to use the Dinan Intake then.

Any help would be highly appreciated from you or anyone. I want to pull the trigger and by these but i don't know if it will fit the Dinan Intake.

For reference, here's a picture of the installed Dinan Intake with the modified stock brace:

I don't think it'll clear the dinan intake unfortunately.

[jello]

Originally Posted by F87source

I don't think it'll clear the dinan intake unfortunately.

Bummer! Thanks anyway OP!

[ZM2]

F87source Any driving impressions?

[F87source]

Originally Posted by ZM2

F87source Any driving impressions?

Hey!

Yup I have a bit of experience now, but I was going to wait till I had time off during the holidays to write it up - along with my radar detector + custom firmware (really cool little project here) review.


But what I can say is that I've tried permutations of strut brace +/- corner brace and I do notice an improved bit of steering feel during hard cornering, I really notice it when I go over curbs or speed bump (at an angle so one wheel contacts first - typical things to do in a low ride height car). It's hard to describe but the steering feels more direct, and there feels like there is less play in the system. In straight line driving I feel nothing, and in all cases there is no increase in nvh. I would also say that when you add the strut brace as well, then I would say that exentuates the tightness feeling a bit more, but it's hard to quantify by how much. But I can say that I think it does improve front end feel of the car, and with the price of a strut brace being really cheap I'd do both.