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E46 M3 (2001-2006) Engine: S54 - Max Hp: 333 hp at 7,900 rpm / 262 lb/ft at 4,900 rpm
Total Produced: 45,000+ - Years Produced: 2001 to 2006.


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Old Sun, Jan-08-2017, 01:14:10 AM   #11
AussieE46M3
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Default Re: CMP Auto Engineering subframe kit

Hi TMSNYC,

I'm preparing an abbreviated version of our welding procedure manual to help those understand the required.

I am doing this during my free time so it will be in a few days time as I'm busy with work right now.
I will let you know when it's available for viewing on our webpage. Sorry for the inconvenience.
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Old Sun, Jan-08-2017, 01:40:45 AM   #12
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Default Re: CMP Auto Engineering subframe kit

Quote:
Originally Posted by AussieE46M3 View Post
Hi TMSNYC,

I am doing this during my free time so it will be in a few days time as I'm busy with work right now.
I will let you know when it's available for viewing on our webpage. Sorry for the inconvenience.
Understood, but this is a product that most likely requires significant alteration to the trunk floor. The illustrated install looks very clean but you're competing against products that have been pretty much "open kimono" about install process so to do an "apples to apples" comparison it would be very helpful to get the full install procedure. Even a PDF of what you send customers would be helpful.
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Old Sun, Jan-08-2017, 01:57:38 AM   #13
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Default Re: CMP Auto Engineering subframe kit

This looks very promising, especially as I was getting ready to pull the trigger on a Mason bar. Keen to see more details on the install.
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Old Sun, Jan-08-2017, 03:33:14 AM   #14
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Default Re: CMP Auto Engineering subframe kit

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Originally Posted by AussieE46M3 View Post
Good afternoon,

Some of you may have seen me posting on Facebook announcing the release of the CMP subframe kit?

it is a design I have been working in my free time for over a year now with consultation with other mechanical engineers. Due to all the interest I was receiving from E46 owners I decided to invest some extra time and turn it into a kit available to the public.

The kit is designed to massively reinforce the rear two of four subframe mounts to prevent any future failures as well as provide a substantial increase in chassis rigidity without being excessively intrusive on the boot cavity.



We have had a few sales already here in Australia so I thought I would take the time to post on the forums to see if the broader M3 community was interested. Based on feedback, the kit gives the back end a more direct and responsive sensation.

I myself am a mechanical engineer / E46 enthusiast who works in the steel industry for a company that makes residential & commercial steel foundations and thus have connections to laser cutters, machinists etc however, I am not associated with body shops or workshops.

The kit consists of 11 laser cut pieces from plate, RHS (rectangle hollow section) and tube + custom bolts and nuts as well as some basic hardware in order to extend the bolt holes without damaging the factory thread.

Attached is a photo of the kit loosely fitted after the sheet metal was removed.



This kit is DIY friendly and only requires the boot trim and a single piece of sheet metal to be removed and can be done on all four wheels. The finished installed kit below.



We have some information available on our webpage (linked below) in the technical section as to why we believe the rear axle carrier panel (better known as the subframe) fails and a brief analysis of the forces experienced and how such stresses are supported.

http://cmpautoengineering.com/technical/

As discussed in our "why we Developed our Kit", this kit was created due to post repair plate failures occurring.
At the time the underside repair was done, the manufactures of such plates did not recommend things like stitch welding the wheel arch join, boot floor to chassis rails or the tops of the front mounts.

All parts are designed using 3D CAD software for pre-determined fitment and precision laser cut and bent using a CNC brake press plate bender for consistency.
The holes cut in the plates align with factory welds for ideal joining and should offer unparalleled chassis rigidity and load distribution.

We currently have a 10% off sale on that ends shortly and if you would like to, please like our facebook page for more updates on this and future products.

https://www.facebook.com/cmpauto/

We would love some feedback on our analysis or if you have any questions we are open to discussing further. We are also available via Email or facebook messenger.



You say you consulted with engineers but what exactly does that mean? What verifiable analysis and testing have you done to support your claims that this solution actually does what it is supposed to do?
This looks like a good solution even with the welding and all and I am all for this if it works. But I personally don't want to shell out $600 without a better explanation for how this system does what it is supposed to do and more importantly how it is better than systems requiring no welding at a similar cost.
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Old Sun, Jan-08-2017, 04:48:24 PM   #15
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Default Re: CMP Auto Engineering subframe kit

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Originally Posted by icecream View Post
You say you consulted with engineers but what exactly does that mean? What verifiable analysis and testing have you done to support your claims that this solution actually does what it is supposed to do?
This looks like a good solution even with the welding and all and I am all for this if it works. But I personally don't want to shell out $600 without a better explanation for how this system does what it is supposed to do and more importantly how it is better than systems requiring no welding at a similar cost.

Most unibody cars usually have the subframes attached to the frame rails or close to them (audi, most newer bmw, etc). This long brace essentially connects the frame rails together with a large, thicker piece of metal instead of paper thin sheet metal which bmw thought would be a good idea to connect our subframes to. Instead of putting the stress on the paper thin floor, it will direct it to the frame rails. Unfortunately, what you're asking for from what I can tell is way out of anyones price range. None of us have the means/money to "verify" whether this works. The best way is R&D which is also probably the cheapest. As an engineer (though not mechanical), I think we can all agree that this is far more effective than simple plates and welding. I have used this basic design for years as well as many club racers have effectively done this same thing for more than a decade connecting mounting points/frame rails/roll cages. Rest assured, this is money well spent. Nice product!
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Old Sun, Jan-08-2017, 04:56:22 PM   #16
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Default Re: CMP Auto Engineering subframe kit

Your website explains your methodology and analysis very well. I'm interested in your product and hope to order by second quarter '17. Thanks.

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Old Mon, Jan-09-2017, 12:52:50 AM   #17
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Default Re: CMP Auto Engineering subframe kit

Hi TMSNYC,

I'll provide a link as soon as I get the chance. Currently at work.

Thanks for the positive support guys.

I'll have the chance to answer questions this afternoon.

Last edited by AussieE46M3; Mon, Jan-09-2017 at 12:56:43 AM.
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Old Mon, Jan-09-2017, 01:12:02 AM   #18
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Default Re: CMP Auto Engineering subframe kit

I am curious how this differs from the VinceBar solution? Not trying to stir the pot, but this looks (at least from the outside) to be essentially the same. Surely, you have encountered his threads and wealth of info during the design process? Can you shed light on this?
2 of Vince's many threads:
http://www.m3forum.net/m3forum/showthread.php?t=551862
http://www.m3forum.net/m3forum/showthread.php?t=529214
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Last edited by Dr M3an M3; Mon, Jan-09-2017 at 01:48:48 AM.
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Old Mon, Jan-09-2017, 11:58:15 PM   #19
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Default Re: CMP Auto Engineering subframe kit

Hi Guys,
Sorry for the lack of responses. I have family here form overseas at the moment who are currently occupying a lot of my time outside of work. Currently at work now so I’ll have to be brief.

I understand the some may not wish to cut their boot interior. Personally took me an hour to trim the lot and put it back in. used chalk, a Stanley knife, hole saw and a jig saw.
The design couldn’t offer the rigidity it does without the increase in vertical cross section or load distribution without the strategic welds it requires. We believed it to be a necessary compromise in boot space.

Regarding your question ‘icecream’, the consultation was with some of the other engineers I had studied with to gain a second opinion or to gain an alternative perspective. The design was based on engineering principles of second moment of inertia with consideration for load distribution.
Rough calculations were performed comparing the change in second moment of inertia at the fail prone areas to determine a rough proportionate increase in rigidity and to find the ideal material thickness of the RHS member. Of course, several things had to be neglected due to several unknown factors.
I had not gathered any deflection data prior to the kit being installed and thus having testing performed without a control would provide data without comparison. Perhaps in future a willing client will allow such test to be performed. Although, based on feedback, the increase in chassis rigidity is noticeable.

We will be posting a more in depth analysis of the kits performance on our webpage in the coming days.

Thanks for the support ‘TheWarHammer’, a lot of other engineers with E46’s hold similar opinion of the product.
The biggest design flaw we found was the fact the majority of load was distributed outward to the wheel arch and supported by very few spot welds. Once that area fails, subsequent failures occur elsewhere. Reinforcing plates are localised and don’t address such design flaws.

Hi Dr M3an.
Not stirring the pot at all. We appreciate these questions. Our design will be discussed in the analysis we will be posting on our webpage however, to summarise for now;

Our design introduces a new chassis member between the existing in a ‘H’ pattern to distribute the point loads directly to the chassis rails rather than through the wheel arch join.

By incorporating a vertical rib between the new RHS and RACP, we have allowed for a combined bending resistance rather than two members in parallel for a significant increase in rigidity across the entirety of the rear axle carrier panel between chassis rails.

We had allowed for the reinforcing plate atop the RACP to reduce elastic deflection within the top face of the RACP panel as the loads passing through the rib and tube could result in reciprocating flex as it is within the centre of a flat face. This plate also ties into all the welds holding the female thread insert.

The chassis legs plates were intended to offer a larger area to distribute load passing through the RHS member rather than just its perimeter and tie into the factory spot welds etc (from memory it was a requirement in the Australian design rules for modified vehicle chassis). Having removed the section of sheet metal exposing the RACP, we identified the gap between the chassis rail and RACP and decided to extend the plate downward to fill the gap linking the members directly to work with the RHS member and has a small leg that wraps around the vertical face of the RACP to catch the other weld supporting the female thread insert.

All components are laser cut/CNC bent for a precise and consistent fitment.

The similairity between out kit and the one ‘Vince’ offers is that we had both identified that the chassis rail is the ideal area to support the RACP rather than shock towers as it is the strongest member within the local area and achieves minimal compromise on the boot cavity.

I am aware of Vince’s work. It was suggested by other members of this forum that I review his analysis during the design process of this kit.
We reviewed every bit of information we could to contribute to achieving the ideal design. His was one many. Having reviewed his proposal, I had performed my own research on my own car to confirm the opinions and analysis of other across the net.

We had chosen to utilise the through bolt method to apply force directly atop the RACP reinforcing plate to relieve stress on some of the joining welds and bring a portion of the force applied closer to the centroid. The design is not dependent on the extended bolts to transfer forces and would function without. It was simply an additional design feature to further contribute to the function of the design.

I’m sorry my brief reply became a long one. I often get carried away talking about this topic.

Last edited by AussieE46M3; Tue, Jan-10-2017 at 12:41:23 AM.
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Old Tue, Jan-10-2017, 04:01:59 AM   #20
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Default Re: CMP Auto Engineering subframe kit

The mere fact that you should be able to supply to Australian E46 owners at a reasonable rate is reason enough for me to support this. Whilst my car appears to be clear of cracking it may not always be so. I'll be eagerly awaiting the installation instructions.
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Discussing CMP Auto Engineering subframe kit in the E46 M3 (2001-2006) Forum - Engine: S54 - Max Hp: 333 hp at 7,900 rpm / 262 lb/ft at 4,900 rpm
Total Produced: 45,000+ - Years Produced: 2001 to 2006. at BMW M3 Forum.com (E30 M3 | E36 M3 | E46 M3 | E92 M3 | F80/X)