Hi Guys, I thought it is finally time to make my first post on the new forum and what a better opportunity than to announce something new!
For those who aren’t familiar with me, my name is Cayn and I design and produce a range of products for several BMW generations under the company name CMP Auto Engineering. When I first started in 2017 the forum offered a lot of support so I thought it would be good to get back on here and be more involved once again.
I’ve been occupied with other generations of BMW lately and am currently part way through a resto-mod on my E92 M3 however, I have been working on a few things for the E46 chassis that I’m very excited to share with you.
I’ve been revisiting my original inventions being the topside reinforcements for the E46 Rear Axle Carrier Panel. With more years and experience under my belt and being well aware of the rising cost of manufacturing I’ve taken some concepts I’ve been contemplating for some years and have made them a reality.
I’m sure many of you here have already reinforced your cars given the wealth of information available here however, I hope that some of this still piques your interest.
I’ll do my best to keep things factual and interesting and if you have any questions, please feel free to ask away. I enjoy the discussion and want to offer any information I can to the BMW community.
Although it has been fun designing something so new for the chassis, there was reason for this decision to evolve the line-up of chassis reinforcements I offer with the previous being discontinued.
looking back on the original topside beam kit, the design approach was tunnel visioned without future planning. At the time I had no intention to add the additional front mount kit or brace. The beam was designed to be entirely sufficient for the rear two mounts with nothing extra. The result being that when the brace was added the combined structure was a lot more than necessary for those two subframe mounts resulting in something that was bulkier and heavier than it needed to be. This perception resonated with a lot of feedback from those wanting a more subtle and lighter solution.
Revisions were made to cut back weight or make the finished install more aesthetic however, it remained substantial. Picture below for reference
On the upside, the chassis became unbelievably rigid and capable of surviving just about any amount of abuse. With some customers pumping out 4 figure horsepower numbers I’m glad it was on the substantial side although, those people are an incredibly small few with the majority not needing that scale of structure.
Other things that were not considered at the time of concepting was compatibility and the sequential nature of the products. Many people wanted a way to reinforce their front two mounts and do something different for their rear mounts however, that wasn’t an option leaving little decision freedom.
Other things such as the reinforcements being sold in kit form and being more substantial made them more fabrication heavy to install adding cost and complexity for customers.
With these things as the major focus I wanted to design something completely revolutionary with a wholistic mindset from the beginning. That resulted in the following design objectives:
-lighter
-Cheaper
-More hidden/aesthetic
-Easier to Install
These objectives would also have compounding economic benefits such as being cheaper to buy, smaller/cheaper to ship and cheaper to install helping to minimise the overall investment to own and maintaining the platform.
In my opinion and hope/think many of you agree that the E46 M3 was in the golden era of driving pleasure compared to many cars now that are very focused on statistical performance. I felt it was both necessary and pleasure to rev the S54 all the way out to really move and felt very ‘chuckable’ and playful in the bends.
Lightness was the highest priority as the S54 isn’t a low-down torque motor. E46 M3’s (like most cars) really come alive with weight reduction which further compliments the playful handling characteristics. The desire was to not change any part of that, just improve upon it.
To start with, the design was separated into front and rear halves with their own respective weld in structure with a complimenting & optional bolt in brace for additional support and chassis rigidity.
The benefit being the front half kits are compatible with any rear kit someone may already have installed.
I can see this post is getting long, so I’ll cut to the chase and pump out the facts.
Please keep in mind the following images are of prototypes and small design revisions have been made to perfect the designs.
Rear Half:
Link to original post: https://www.instagram.com/p/CggDpJqppFb/?utm_source=ig_web_copy_link
The rear half uses a similar design approach as the previous by extending the frame rail directly to the top of the RACP to provide a direct link between the previously separate hollow section structures and adding a beam in between to increase vertical cross section and thus rigidity. The difference now is that the beam sits flush with the boot floor and consists of two pieces of folded sheet metal that clamshell together to form a hollow section that mimics the profile of the RACP. This replaces a portion of the spare wheel well sheet metal that is removed during install for an aesthetic and hidden finish.
The lower portion is stitch welded in with the upper portion also using plug welds at the most forward edge for an almost stock look. Between the two pieces of sheet metal there is a very short pieces of roll cage tube between aligned with the centre of the rear mounts. Centred within this tube against the top layer are female threads that provide a rigid and secure landing for the brace structure with a direct load path to the rear subframe mount.
While the weld in beam is completely hidden beneath the boot trim, the brace is a prefabricated and powder coated bolt-together structure that can be assembled and installed as the interior goes in with basic hand tools.
The bolted connection provide a range of adjustment capable of accounting for the install tolerances of the weld in support beneath as well as the dimensional differences between coupe & sedan chassis.
The brace itself uses a single piece of square hollow section spanning the towers for its superior bending stiffness over circular and to provide a flat mating face for the other components. The drop downs and tower mounts are made from folded & welded sheet metal to further reduce cost, complexity and weight.
Front Half:
Link to original post: https://www.instagram.com/p/ChG_40fheM5/?utm_source=ig_web_copy_link
The front half is where things got creative. Taking a similar approach to the previous front mount kit, the design introduces a rigid structure that spans the distance of the frame rails and links directly to the front two, rear subframe mounts however, this time is completely flush with the floor except for the wedges at each end.
This reinforcement welds to the top of the front two mounts with a fin between. Additional stitches are applied securing it to the back of the underside plates. The wedges at either end are three dimensional in order to provide a rigid connection to the frame rail and lap the factory rear bulkhead stitch weld that has reported cases of tearing.
The brace for the front half was designed with the desire to be as in line with the force vector as possible and not cantilevered and took inspiration from the fact that sedans boast greater torsional rigidity over their coupe counterparts mostly due to a sheet metal wall separating the cabin from the boot. Unlike the sheet metal wall, this brace is entirely bolt in using two existing holes in the bulkhead with two new holes needing to be drilled and bolts as close as possible to the front two, rear subframe mounts either side of the welded in fin.
The brace is made of a single piece aluminium that sits almost flush against the rear seats with no intrusion on the boot cavity (unless you need the rear seats folded down) yet offering a significant and noticeable increase in torsional rigidity.
To install the brace is simple as once again as no fab is required. Some interior pieces do need to be trimmed however, only in places not visible once re-assembled.
The brace is intended to be sold in raw aluminium, however, could be powder coated any colour of your choice for an aesthetic show piece when opening the boot.
Reflecting on the design objectives I can share the following results:
Lighter:
The previous reinforcements in their final revisions weighed the following:
Rear weld in beam = 6.6kg/14.5 pounds
Front weld in extension = 4.4kg/9.7 pounds
Rear brace = 6.2kg/13.6 pounds
Combine total = 17.2kg/37.84 pounds
The new kits came in at the following weight figures:
Rear Beam = 2.9kg/6.38 pounds = Reduction of 3.7kg/8.14 pounds (56%)
Front Beam = 1.7kg/3.74 pounds = Reduction of 2.7kg/5.94 pounds (61%)
Rear Brace = 4.23kg/9.3 pounds
Front Brace = 1.56kg/3.43 pounds
The combine new braces vs previous = 0.41kg/0.9 pounds in weight reduction (6.6%).
The reason the weld in supports witnessed such significant reductions in weight compared to the braces is due to the point I made earlier where the original weld in kits were not designed to have a bolt in brace acting in support. Thus, when designing these new solution and accounting for the full extent of additional structure they had the most room for refinement.
My personal recommendation for those without significant power adders or running true coil over rear suspension is both weld in supports with just the front brace bolted in. From my own experience installing and testing the prototypes, this combination provided the most significant increase in felt stiffness (and thus assumed torsional rigidity) while providing the most stock aesthetic with zero intrusion on boot space.
This combination is also the lightest with a total weight of 6.16kg or 13.5 pounds (64.2% lighter than previous combine total) and comes at an incredibly competitive price.
Cheaper:
This objective was a huge success. The revised construction methods accounted for within the design cut the cost downs significantly which is passed on within the sale price.
Although we’ve offered a reduced price recently to clear stock of the old generation of kits, they’re standard price is as follows:
Previous rear beam = $499 Aud or ~$339 USD
Previous front beam = $299 Aud or ~$203 USD
Previous Brace = $499 Aud or ~$339 USD
New rear Beam = $199 Aud or ~$135 USD (60% Less)
New front beam = $169 Aud or ~$115 USD (43.5% Less)
New rear brace = $349 Aud or ~$237 USD (may vary)
New front brace = $229 Aud or ~$155 USD (in raw aluminium)
Due to larger volume of sheet metal parts ordered, small saving were made on the production of the underside reinforcement plates I offer which has been passed on in the sale price having been reduced by 10% to $179 Aud ($121.5 USD) from $199 Aud.
Easier to Install:
While the new braces combine may equate to more than the previous, the old design was sold in kit form like a roll cage and required significant fab work to assemble & install. This often equated to as much if not more than the cost of the kit to begin with. The new design being a prefabricated part could be done by any competent DIY’er or by a workshop in a matter of moments.
The same objective to reduce fab applied to both weld in reinforcements during the design stages was successful with a noticeable reduction in install time required. Being very experienced with the kits and the install procedure, both kits were installed in a single day. This may vary depending on chosen fabricator however, overall offers further reduction in cost to E46 owners.
More Aesthetic/Hidden:
They say the beauty is in the eye of the beholder so perhaps not everyone will agree however, I personally think the revised reinforcements are very sexy.
The general consensus from feedback was that most owners wanted the weld in reinforcements hidden with the braces offering minimal obstruction which I feel has been achieved. Please let me know your thoughts 😊
That concludes the design objectives and the bulk of the information I wanted to share. If anyone is interested in any of these reinforcement solutions, they will come with comprehensive instructions. I also intend to do a video detailing the steps of installing each kit before the end of the year.
I appreciate anyone who took the time to read the above. It’s one of those things that become much longer than expected despite trying to keep it somewhat short and sweet.
For anyone interested stock is due to arrive September 21st with first dispatch commencing Monday the 26th.
We will be offering pre-orders on the site very soon at a 10% off compared to the above figures. This will exclude the rear brace as we cannot lock in the cost of powder coating at this point in time hence why it may vary.
If anyone has any questions regarding the above, please feel free to ask. I’m happy to chat.
For those who aren’t familiar with me, my name is Cayn and I design and produce a range of products for several BMW generations under the company name CMP Auto Engineering. When I first started in 2017 the forum offered a lot of support so I thought it would be good to get back on here and be more involved once again.
I’ve been occupied with other generations of BMW lately and am currently part way through a resto-mod on my E92 M3 however, I have been working on a few things for the E46 chassis that I’m very excited to share with you.
I’ve been revisiting my original inventions being the topside reinforcements for the E46 Rear Axle Carrier Panel. With more years and experience under my belt and being well aware of the rising cost of manufacturing I’ve taken some concepts I’ve been contemplating for some years and have made them a reality.
I’m sure many of you here have already reinforced your cars given the wealth of information available here however, I hope that some of this still piques your interest.
I’ll do my best to keep things factual and interesting and if you have any questions, please feel free to ask away. I enjoy the discussion and want to offer any information I can to the BMW community.
Although it has been fun designing something so new for the chassis, there was reason for this decision to evolve the line-up of chassis reinforcements I offer with the previous being discontinued.
looking back on the original topside beam kit, the design approach was tunnel visioned without future planning. At the time I had no intention to add the additional front mount kit or brace. The beam was designed to be entirely sufficient for the rear two mounts with nothing extra. The result being that when the brace was added the combined structure was a lot more than necessary for those two subframe mounts resulting in something that was bulkier and heavier than it needed to be. This perception resonated with a lot of feedback from those wanting a more subtle and lighter solution.
Revisions were made to cut back weight or make the finished install more aesthetic however, it remained substantial. Picture below for reference
On the upside, the chassis became unbelievably rigid and capable of surviving just about any amount of abuse. With some customers pumping out 4 figure horsepower numbers I’m glad it was on the substantial side although, those people are an incredibly small few with the majority not needing that scale of structure.
Other things that were not considered at the time of concepting was compatibility and the sequential nature of the products. Many people wanted a way to reinforce their front two mounts and do something different for their rear mounts however, that wasn’t an option leaving little decision freedom.
Other things such as the reinforcements being sold in kit form and being more substantial made them more fabrication heavy to install adding cost and complexity for customers.
With these things as the major focus I wanted to design something completely revolutionary with a wholistic mindset from the beginning. That resulted in the following design objectives:
-lighter
-Cheaper
-More hidden/aesthetic
-Easier to Install
These objectives would also have compounding economic benefits such as being cheaper to buy, smaller/cheaper to ship and cheaper to install helping to minimise the overall investment to own and maintaining the platform.
In my opinion and hope/think many of you agree that the E46 M3 was in the golden era of driving pleasure compared to many cars now that are very focused on statistical performance. I felt it was both necessary and pleasure to rev the S54 all the way out to really move and felt very ‘chuckable’ and playful in the bends.
Lightness was the highest priority as the S54 isn’t a low-down torque motor. E46 M3’s (like most cars) really come alive with weight reduction which further compliments the playful handling characteristics. The desire was to not change any part of that, just improve upon it.
To start with, the design was separated into front and rear halves with their own respective weld in structure with a complimenting & optional bolt in brace for additional support and chassis rigidity.
The benefit being the front half kits are compatible with any rear kit someone may already have installed.
I can see this post is getting long, so I’ll cut to the chase and pump out the facts.
Please keep in mind the following images are of prototypes and small design revisions have been made to perfect the designs.
Rear Half:
Link to original post: https://www.instagram.com/p/CggDpJqppFb/?utm_source=ig_web_copy_link
The rear half uses a similar design approach as the previous by extending the frame rail directly to the top of the RACP to provide a direct link between the previously separate hollow section structures and adding a beam in between to increase vertical cross section and thus rigidity. The difference now is that the beam sits flush with the boot floor and consists of two pieces of folded sheet metal that clamshell together to form a hollow section that mimics the profile of the RACP. This replaces a portion of the spare wheel well sheet metal that is removed during install for an aesthetic and hidden finish.
The lower portion is stitch welded in with the upper portion also using plug welds at the most forward edge for an almost stock look. Between the two pieces of sheet metal there is a very short pieces of roll cage tube between aligned with the centre of the rear mounts. Centred within this tube against the top layer are female threads that provide a rigid and secure landing for the brace structure with a direct load path to the rear subframe mount.
While the weld in beam is completely hidden beneath the boot trim, the brace is a prefabricated and powder coated bolt-together structure that can be assembled and installed as the interior goes in with basic hand tools.
The bolted connection provide a range of adjustment capable of accounting for the install tolerances of the weld in support beneath as well as the dimensional differences between coupe & sedan chassis.
The brace itself uses a single piece of square hollow section spanning the towers for its superior bending stiffness over circular and to provide a flat mating face for the other components. The drop downs and tower mounts are made from folded & welded sheet metal to further reduce cost, complexity and weight.
Front Half:
Link to original post: https://www.instagram.com/p/ChG_40fheM5/?utm_source=ig_web_copy_link
The front half is where things got creative. Taking a similar approach to the previous front mount kit, the design introduces a rigid structure that spans the distance of the frame rails and links directly to the front two, rear subframe mounts however, this time is completely flush with the floor except for the wedges at each end.
This reinforcement welds to the top of the front two mounts with a fin between. Additional stitches are applied securing it to the back of the underside plates. The wedges at either end are three dimensional in order to provide a rigid connection to the frame rail and lap the factory rear bulkhead stitch weld that has reported cases of tearing.
The brace for the front half was designed with the desire to be as in line with the force vector as possible and not cantilevered and took inspiration from the fact that sedans boast greater torsional rigidity over their coupe counterparts mostly due to a sheet metal wall separating the cabin from the boot. Unlike the sheet metal wall, this brace is entirely bolt in using two existing holes in the bulkhead with two new holes needing to be drilled and bolts as close as possible to the front two, rear subframe mounts either side of the welded in fin.
The brace is made of a single piece aluminium that sits almost flush against the rear seats with no intrusion on the boot cavity (unless you need the rear seats folded down) yet offering a significant and noticeable increase in torsional rigidity.
To install the brace is simple as once again as no fab is required. Some interior pieces do need to be trimmed however, only in places not visible once re-assembled.
The brace is intended to be sold in raw aluminium, however, could be powder coated any colour of your choice for an aesthetic show piece when opening the boot.
Reflecting on the design objectives I can share the following results:
Lighter:
The previous reinforcements in their final revisions weighed the following:
Rear weld in beam = 6.6kg/14.5 pounds
Front weld in extension = 4.4kg/9.7 pounds
Rear brace = 6.2kg/13.6 pounds
Combine total = 17.2kg/37.84 pounds
The new kits came in at the following weight figures:
Rear Beam = 2.9kg/6.38 pounds = Reduction of 3.7kg/8.14 pounds (56%)
Front Beam = 1.7kg/3.74 pounds = Reduction of 2.7kg/5.94 pounds (61%)
Rear Brace = 4.23kg/9.3 pounds
Front Brace = 1.56kg/3.43 pounds
The combine new braces vs previous = 0.41kg/0.9 pounds in weight reduction (6.6%).
The reason the weld in supports witnessed such significant reductions in weight compared to the braces is due to the point I made earlier where the original weld in kits were not designed to have a bolt in brace acting in support. Thus, when designing these new solution and accounting for the full extent of additional structure they had the most room for refinement.
My personal recommendation for those without significant power adders or running true coil over rear suspension is both weld in supports with just the front brace bolted in. From my own experience installing and testing the prototypes, this combination provided the most significant increase in felt stiffness (and thus assumed torsional rigidity) while providing the most stock aesthetic with zero intrusion on boot space.
This combination is also the lightest with a total weight of 6.16kg or 13.5 pounds (64.2% lighter than previous combine total) and comes at an incredibly competitive price.
Cheaper:
This objective was a huge success. The revised construction methods accounted for within the design cut the cost downs significantly which is passed on within the sale price.
Although we’ve offered a reduced price recently to clear stock of the old generation of kits, they’re standard price is as follows:
Previous rear beam = $499 Aud or ~$339 USD
Previous front beam = $299 Aud or ~$203 USD
Previous Brace = $499 Aud or ~$339 USD
New rear Beam = $199 Aud or ~$135 USD (60% Less)
New front beam = $169 Aud or ~$115 USD (43.5% Less)
New rear brace = $349 Aud or ~$237 USD (may vary)
New front brace = $229 Aud or ~$155 USD (in raw aluminium)
Due to larger volume of sheet metal parts ordered, small saving were made on the production of the underside reinforcement plates I offer which has been passed on in the sale price having been reduced by 10% to $179 Aud ($121.5 USD) from $199 Aud.
Easier to Install:
While the new braces combine may equate to more than the previous, the old design was sold in kit form like a roll cage and required significant fab work to assemble & install. This often equated to as much if not more than the cost of the kit to begin with. The new design being a prefabricated part could be done by any competent DIY’er or by a workshop in a matter of moments.
The same objective to reduce fab applied to both weld in reinforcements during the design stages was successful with a noticeable reduction in install time required. Being very experienced with the kits and the install procedure, both kits were installed in a single day. This may vary depending on chosen fabricator however, overall offers further reduction in cost to E46 owners.
More Aesthetic/Hidden:
They say the beauty is in the eye of the beholder so perhaps not everyone will agree however, I personally think the revised reinforcements are very sexy.
The general consensus from feedback was that most owners wanted the weld in reinforcements hidden with the braces offering minimal obstruction which I feel has been achieved. Please let me know your thoughts 😊
That concludes the design objectives and the bulk of the information I wanted to share. If anyone is interested in any of these reinforcement solutions, they will come with comprehensive instructions. I also intend to do a video detailing the steps of installing each kit before the end of the year.
I appreciate anyone who took the time to read the above. It’s one of those things that become much longer than expected despite trying to keep it somewhat short and sweet.
For anyone interested stock is due to arrive September 21st with first dispatch commencing Monday the 26th.
We will be offering pre-orders on the site very soon at a 10% off compared to the above figures. This will exclude the rear brace as we cannot lock in the cost of powder coating at this point in time hence why it may vary.
If anyone has any questions regarding the above, please feel free to ask. I’m happy to chat.
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