"In this Special Series about the Custom BMW Performance style CS seats, I document the process to match my Genuine BMW Performance driver seat with a replica passenger seat in collaboration with David at Recovered Workshop. 

In this entry, I document the first steps in re-creating the BMW Performance signature design with its foam patterns and we give you the tools to spot shops that skip on critical detail."
- Matt

It's about the little things. 

In the second entry to this Special Series, I compared the original BMW Performance seat to the Recaro CS. I touched on the various designs, upholstery and functionality differences between both with the seats fully assembled. 

Beyond the upholstery differences, the ribs are the signature design difference between both seats.

The foam.

The foam is arguably the biggest difference between both seats, and the most difficult to accurately recreate in aesthetics, and feel. BMW performance had a entirely new mold to create the foam. In our case, we chose to modify the Recaro CS original foam to recreate the original pattern.

It's what M owners are most willing to pay more for but they don't always get what're paying for. 

Spotting the differences.

Some upholstery shops that have created replicas do not bother with reworking the foam to the original specifications. As a result, the ribs' bulges have limited depth, sit lower and they cannot reuse the original stitching method of BMW's Performance seat. 

We understand why: this process requires time, and dexterity. You cannot speed up this process using laser cutting machines nor is creating a new mold economically feasible.

This means added cost that some shops determine their market isn't willing to pay for [...] or won't know any better. To the unknowing minds, they wouldn't be able to tell or feel the differences. 

Discovering and learning about upholstery differences is like learning about orange peel - once you know, you know. Having had the original BMW Performance side by side with a Recaro CS and cut into them, we know. 

David and Louis know, and have created similar patterns before.

The original stitching. 

On the original BMW Performance seats, you will not find any visible stitches on the ribs, and they will have a pronounced, accentuated depth between each rib.

Instead, they will simply stitch the rib lines over the original Recaro CS without any changes to the foam. They use a stitching method producing lesser quality aesthetics with higher probabilities of stitching coming apart over tine. 

The original BMW Performance has a more complex type of stitching that requires the added depth of the ribs and its velcro. 

Here's a crude comparison: the top ribs showcase the original method, whether the lowest rib shows what some shops do. The stitching is visible, and the bulge is less. 

The rib's shape and depth.

In order to achieve this, Recaro had a custom foam mold created for BMW. It adds height to the center section and creates cavities that create the pronounced relief between each rib. We measured each rib and created patrons with its curvatures. 

The foam's ribs sit higher than the standard Recaro CS.

The original BMW Performance foam has cavities cut out to enhance the bulging aesthetics of the ribs. We will need to cut into the foam, and glue in the velcros upon which the covers will rest. 

Part 1: Filling in the foam. 

The Recaro CS foams have cut outs that are not on the original BMW Performance design. Before we'll cut into the foam, we'll start to fill in the gaps. 

Can you spot the differences? We have a lot of work ahead of us. 

All the top cut outs will need to be filled in. 

Before getting to even filling in the foam, the Recaro CS foams need to be de-trimmed further by removing clips and velcros that will not be re-used. 

The prototype's foam process.

To fill in the gaps, we we will be first using recycled, bonded polyurethane foam. It is commonly used for commercial applications where durability are required such as motorcycle seats. 

Notes on foam processes.

Custom mixes of pourable flexible urethane foam are currently being tested to match the original BMW Performance foam density.

The goal is to reduce time of production, without cutting down on quality. If there is sufficient demand and we can dial in density of pour in flexible foams, we will explore machining a mold for the entire seat foams.

Recycled, bonded foam feels mushy with a similar firmness to the original CS foam. It's a good material - but it's a time intensive process.

Adhesives are first sprayed into the cavities. These need to dry and then become sticky - unlike most glues you might be used to in your daily life. 

This adhesive is a low VOC chemical - but still, air filtration masks are required.  

Foam was cut out to roughly match the shape of the gaps to fill in. 

It wouldn't match perfectly right off the bat, of course. It's part of the process. 

At the prototype stage, we're spending way too much time doing this. It's part of the investment into creating the custom seat program. 

These are areas of the production process that will eventually be streamlined. Here, it was all about a craftsman's skills, and his makeshift tools: yes, that's an electrical roast beef knife. 

Not bad, but not there yet. 

Dave pulled out sanding pads. My experience mostly resolves around paint, body & detailing. This was all hilariously similar to me. 

Matt: So, Dave - when do you stop? (and not mess up my already expensive Recaro CS's foam.)

David: Right here man. Follow the signs. 

Is it worth it?

After all these years, I continue to believe in transparency and sharing the information as I learn more about it. When sourcing and developing products, I optimize, most times, for 1:1 or enhanced re-creation. 

Now that you know, whether it is worth it will be up to you to determine. If you've spent thousands on a replica seat thinking you had a 1:1 replica, I empathize.

This will be a significant cost difference between our re-creations and others. 

Filling in the foam was a third of the work.

Creating shapes is a far more complex, and risky process. 

Up next: we create the rib's signature aesthetics from scratch.