[AussieE46M3]

Afternoon Beamrup,

Just letting you know we've updated our install manual and uploaded the revised version on our webpage if you would like to review the changes.

http://cmpautoengineering.com/techni...me-solution-2/

[t3ddftw]

As someone considering purchasing Vince's bar, what would you say are the advantages to your solution over his, if any?

Btw, thank you for designing this product! It's great to see that this car is still being improved by the community, even 16 years after its initial introduction.

[Beamrup]

As someone considering purchasing Vince's bar, what would you say are the advantages to your solution over his, if any?

Btw, thank you for designing this product! It's great to see that this car is still being improved by the community, even 16 years after its initial introduction.

Based on my research and insight as an engineer, I can honestly say both products are excellent and very comparable.

I'll attempt to compare differences here:

CMP & VINCE BAR SIMILARITIES
-Both work by securely connecting a steel bar between the chassis legs. This allows the sub frame to directly transmit loads to the chassis legs rather than the thin sheet metal floor.
-Both are best used in conjunction with either Redish or TMS underside reinforcement plates.
-Both allow full use of the trunk.

VINCE BAR UNIQUE FEATURES/ADVANTAGES
-Can be riveted/epoxied or welded in place. I personally recommend the welded route as I'm a much more conservative builder.
-Is completely invisible once installed. There is no knowing it was even there.
-Easier to DIY.

CMP BAR UNIQUE FEATURES/ADVANTAGES
-The bar between the chassis legs has a much larger cross sectional area. Its a bigger, beefier bar.
-It is visible once installed, it does not hide completely like the Vince Bar.
-The larger exposed flat surface of the bar allows for easy welded upgrades in the future, such as a tie into the shock towers like the Mason Brace.

I Plan to connect my CMP bar to a modified Mason GTR brace in the future. So, for me, the CMP is the way to go.

Afternoon Beamrup,

Just letting you know we've updated our install manual and uploaded the revised version on our webpage if you would like to review the changes.

http://cmpautoengineering.com/techni...me-solution-2/

The changes are absolutely perfect and clarify things wonderfully! Nice work! I intend to place my order ASAP. I'll be sure to document the install by Lang Racing here.

[AussieE46M3]

Morning T3ddftw,

As someone considering purchasing Vince's bar, what would you say are the advantages to your solution over his, if any?

Btw, thank you for designing this product! It's great to see that this car is still being improved by the community, even 16 years after its initial introduction.

Thanks for the support. This kit was born from necessity. I personally had experienced major failure, followed by minor failure in the rear mount area prompting me to investigate and design a solution.

I’ve covered the differences in design previously on page 2, post #19 that you might be interested in. We are working on a technical section to cover the advantages on our webpage. It is yet to be published.

For the time being I can provide a simple explanation of the major key differences. In short, they are;

1. Significant increase in chassis rigidity across the width of the RACP.

2. Picks up loads and ties into the original joins between structural components.

1, Much like Beamrup said, the increase in rigidity is due to stronger members and a greater vertical cross section. The member is also linked directly to the chassis rails with a reinforcing plate between to distribute load over a larger area and provide localised strengthening. The result is not only a reinforced 'subframe' but an increase in feel and responsiveness.

To help visualise, the cross section of our kit resembles a universal beam with square openings top and bottom of a vertical rib when installed. Compared to a small square member directly atop the RACP.

The advantage of this is that the greater bending resistance of the members is further amplified by its distance from the combined centroid rather than just acting in parallel to one another. (I = Ic + A*d).

2, If you view the install manual available on our webpage you will see that our kit has strategic weld locations and sequence to directly link into the original welds for the female thread insert within the RACP as well as the spot welds running the length of the chassis legs.

The advantage of this is that it allows for a more direct load path and doesn’t introduce new stresses within the sheet metal of the RACP and chassis legs. The RACP top plate also acts as a repair plate for a known crack area on the top face of the RACP. The point loads are transferred to the RHS member by a vertical tube section that links directly to the threaded insert within the RACP. The tube also has an internal bolt to bring some of the applied load closer to the centroid and relieve some of the stress on the joining welds.

If a major joining weld for the kit were applied with a distance to the join which load is applied to the original RACP, the thin sheet metal between would have to transfer the stresses. This would introduce new stresses.

Let me know if that answers your questions. If you have any further questions please let me know. We have performed calculations on the changes in moment of area to support our claims that will be in the aforementioned technical section.

Regarding your statement Beamrup, If you would like, we could extend the tube section slightly for your kit in order for you to attach the GTR style brace?

The flat face or the RHS has a greater potentially to oscillate up and down than the vertical face that the tube is tied into. It was one of our design considerations to eliminate minute flex.

[Beamrup]

Regarding your statement Beamrup, If you would like, we could extend the tube section slightly for your kit in order for you to attach the GTR style brace?

The flat face or the RHS has a greater potentially to oscillate up and down than the vertical face that the tube is tied into. It was one of our design considerations to eliminate minute flex.

I'm not sure I completely follow what you're suggesting.

After installing the CMP bar, my plan is to install a Mason Engineering Rear Strut bar. Then, I'd do some custom fab to tie the CMP and strut bar together.

This pic should demonstrate what I'm trying to do:

[M3 dude]

not necessary. just get a gtr style rear bar and attach that.

the mason bar is reduntant after bracing the bottom. if you want to tie the rear shocks, just get a rr strut brace.

[AussieE46M3]

Hi Beamrup,

Adding a strut brace that ties down into our kit will allow for an ideal resultant force to that which the shocks apply, provided it cover the shock tops. This will prevent mushrooming of the rear shock towers and add further rigidity to those suspension points.

To explain what I meant I've attached an image taken of one of the genuine road going GTR's.



See how the tube section is the primary mount point for the 'W' configuration? We could extend the tube section in order for a similar construct to tie into our kit if you'd like?

We had considered developing a strut brace that would do so in future.

Given the kit already reinforces the subframe and a brace would only support the shock towers, relatively small and light weight tube section could be utilised.

For those with an interest in the M3 GTR, I've provided the link to where the image was found. Several good shots of both the street and race variants at many angles are there. The brace in the original race car can also be seen.

http://f30.bimmerpost.com/forums/sho....php?t=1159057

One thing worth noting is that given BMW themselves fitted a brace over the rear mounting points, leads to believe they were aware of the design flaw in late 2001.

[Beamrup]

See how the tube section is the primary mount point for the 'W' configuration? We could extend the tube section in order for a similar construct to tie into our kit if you'd like?

We had considered developing a strut brace that would do so in future.

Given the kit already reinforces the subframe and a brace would only support the shock towers, relatively small and light weight tube section could be utilised.

For those with an interest in the M3 GTR, I've provided the link to where the image was found. Several good shots of both the street and race variants at many angles are there. The brace in the original race car can also be seen.

http://f30.bimmerpost.com/forums/sho....php?t=1159057

One thing worth noting is that given BMW themselves fitted a brace over the rear mounting points, leads to believe they were aware of the design flaw in late 2001.

OMG. I WANT THAT! Yes, lets definitely extend the tubes so I can connect to the Mason Strut Bar. It sounds like the path you're recommending at this time is to fabricate and weld the "W" sections between the extended CMP tubing and the Mason Strut Bar. Correct?

[Obioban]

Originally Posted by AussieE46M3

One thing worth noting is that given BMW themselves fitted a brace over the rear mounting points, leads to believe they were aware of the design flaw in late 2001.

Or they were just stiffening up the chassis for homologation purposes (seeing as that was the point of the road going GTR in general).

[STAATS]

Originally Posted by Beamrup

OMG. I WANT THAT! Yes, lets definitely extend the tubes so I can connect to the Mason Strut Bar. It sounds like the path you're recommending at this time is to fabricate and weld the "W" sections between the extended CMP tubing and the Mason Strut Bar. Correct?

I don't really want to do my Australian brother out of a sale here but I think if you are going to get the Mason Engineering GTR Rear Strut setup then there is no huge push to get the CMP subframe support or the VinceBar for the rear as well (the Mason Engineering GTR bar does a very similar job it just sends the loads through the strut towers down into the chassis rail... it isn't the most elegant solution but as it is triangulated between both strut towers and you get the added bonus of additional torsional rigidity it makes it a pretty good option + no welding)... at that point if you did a bolt-through at the front (using Vince's method or any number or the other methods) and had reinforcement plates (strongly recommend Redish Motorsport over anything else) then you have dealt with the issue... well as best we know how at this point...

If you are going to go to the effort of a weld in system such as the CMP system and modification of a ready to bolt in solution like the Mason Engineering GTR bar then you might be better off scraping both ideas and getting the fabricator/welder you had planned to weld in your CMP kit / modify your GTR bar to instead custom fabricate you a Road GTR type bar (but take the time when you are there to add the additional insurance of a support between the chassis rail and the bottom subframe bolt point of the GTR bar (essentially emulating the CMP or VinceBar type solution)

I did at a time consider doing the VinceBar and Mason Engineering GTR bar in parallel but the cost to benefit just isn't there providing you have Redish Motorsport plates and add a solution for the front mounts (ie bolt throughs)... Yes the GTR bar adds additional stress to the strut towers but due to the triangulation it is spread across both of them...