Updating the S15’s Seat Delete

Six or so months of hibernation provides plenty of time for ideas to start forming and things to snowball a little bit. At the end of the ’21 season the S15 sported a simple closeout panel (seen below) and some lightly trimmed OEM side panels to frame the Miracle Cross Bar and I was very pleased with the overall look. Come spring ’22 however, it left the garage with some additional paneling, more bracing, and even some LEDs.

Having all winter to look at the S15 and ponder what exactly to tackle as part of the next round of updates had me continually coming back to the back half of the interior. I was indeed happy with what I had built, but couldn’t shake the urge to push myself and try taking it a bit further – and then it ended up going even further than originally intended anyway as these things often do (remember when I sent Speedy a few panels for a repaint and by the end of the same week they had the entire car for a colour change?).

In the end the car emerged this year with what you see above: a now fully sealed off interior, illuminated display case for a new rear strut bar, and easy access to the rear dampers so I could more easily change suspension settings without an hour of disassembly first (or risk of wearing out OEM clips and panels by constantly removing them).

A few days ago I published the video showcasing some of the work that went into this seat delete update, and as promised I now have the photos and more detailed breakdown of the entire procedure. For an overview you can click Play above and check out the video, and for the full details you can continue scrolling to what’s below.

We might as well start off with a final look at the 2021 setup before the back half of the interior was removed yet again, to begin the measuring and mocking up of the new pieces. The upholstered panel you see here was constructed from 1/2″ MDF as material prices were insane at the time and I had ample supply of this still kicking around from prior projects. It’s not as lightweight as it could be (uh oh, do I see the beginning of V3.0 being suggested here?) but is still easy to handle and does the job perfectly well. As noted in the video it was retained for this year’s setup although the back edge was trimmed slightly to account for the new backboard, and it was reupholstered with a new material to match as well.

I can honestly say the back half of this car’s interior has come out more often than the oil has been changed, and of course I’m not skimping on maintenance. As you can see, the trunk was stripped bare as well although I still didn’t (and still don’t) have a complete set of OEM panels for it – the few pieces that were present though all had to make way.

The first piece to go in as part of this update was a new Cusco rear strut bar. There are two main kinds of rear strut bars for S15s: those that run above the rear parcel shelf, and those that run below. With the Miracle Bars already in place (and not wanting to cut into the parcel shelf trim) a bar that ran above was ruled out, but one that ran below would never be visible – and this is where the first crazy idea originated. Looking at the options available I selected this Cusco piece specifically because the signature blue fit with the car’s colour scheme, but more importantly the middle bar itself matched the size and look of the Miracle pieces.

Disassembled, the installation started with the two end plates being secured before the bar could then be refit in between and tightened down.

With that in place it was then time to start working on the initial draft of the backboard. I picked up a number of sheets of 1/4″ hardboard, which would be more than strong enough but also be very lightweight. After a cardboard template I used a first piece of hardboard to test ideas and continually tweak the fitment before transferring all of the dimensions to a fresh panel and cutting out the proper copy.

That first draft was soon cut to size and bolted in place using the existing mounting points for the seat back retainers. I grabbed a few bungees to string between the Miracle Bar mounts which then allowed me to visualize what the panel would look like with them back in place, while keeping them safely tucked away. Fitting them is not only a nuisance, but they’re rather expensive so I take great care to not ever mark them.

With the first test looking good so far the backboard was then marked from behind, removed again, and cut to begin trying out the idea I had for displaying the Cusco bar. While there were many sketches done beforehand, nothing beats seeing something in the real world and as soon as I refit the panel I realized this first iteration of the cutout would not fly. I had merely sized the opening to keep the bar centered in it and cut a rectangle, but it didn’t look right so a revision was in order. The slot was too narrow and too…simple looking.

I then decided to forgo having the bar in the center of the coming window, and dropped the opening down as far as I could for it to line up with the bottom of the display case – more on that piece shortly. I also decided to add some interest to the cutout by having the bottom angle up to meet the sides, which made the biggest improvement. Having the bungees in place also allowed me to match the cutout’s angles to that of the bungees and therefore the cross bar.

At this point I also started looking further into the inclusion of access panels for the dampers. I had mentioned in the video that I was originally planning on having some damper extenders come through the backboard, but the angles turned out to be too sharp to the point where they would merely bind. With that off the table, I figured I could just take advantage of the room afforded by the sheetmetal in the car (note how it drops off, leaving a nice hand-sized hole under the parcel shelf trim) and make some removable covers. For this first copy of the backboard I merely cut off the top corner (matching the angle to the sheet metal behind) but changed my approach when it came to the final version so that the top of the panel would be seamless from side to side.

Pizza time. Seeing car parts strewn about, tools and a Workmate in the driveway, and food being delivered is the sign to my neighbours that a show is around the corner. Doug usually pops over around this time to see what I’m up to as well. Haha

With everything looking good at this point I grabbed a fresh piece of hardboard, marked out the final measurements, and got to cutting. Hilariously, while I do have a much larger Workmate as well (that would have been much better suited for this project) it was serving as a temporary stand for the TV in my garage that was waiting to be mounted so I made do with the mini version instead.

As I mentioned above I decided it would look much better (when looking through the back window) if the top of the backboard was seamless so I changed up the access panels and cut openings into the piece instead of just lopping off the top corners. This would also solve the question of how to secure them, as they could simply pressure-fit into these cutouts. In before socks and sandals comments.

Once fully cut, I also made a tracing of the final backboard to save away in our template collection; most of the various splitters, seat deletes, and other random pieces we’ve made over the years have templates filed away in case we ever need to make more copies in the future.

At last, the main component was ready to go! I made sure to test fit it one final time before upholstery just in case anything had to be adjusted, but it was set!

Back out of the car, it was fully wiped down before it and the new fabric were sprayed with adhesive and left to set for a few minutes. Once tacky, the covering began! I was working by myself this night so I did the backboard one third (or so) at a time – here you can see I’ve sprayed enough adhesive for the middle section of the panel to be upholstered next.

It wasn’t long before the fabric was all in place, wrapped around the edges, and trimmed. At last I could bolt this panel in place (almost for good at this point) and see what it looked like! Incidentally the fabric was a lucky find at a local Fabricland that, in person, is nearly spot-on for the OEM carpet and parcel shelf. I made sure to buy plenty. 

With the main piece of the puzzle set it was then time to make the final version of the “display case”, as we refer to it. You’ll have seen the first iteration of it in some of the above photos, with very rough cuts to check clearances around the rear strut bar and test ideas for just how it would assemble and mount in the car.

As with the backboard, I transferred final measurements to some fresh material and cut out panels that fit around the bar tightly. Since the display case was designed to slide in from the trunk with the bar already in place (allowing for quick and easy removal of it so I can clean the backside of the acrylic that ultimately was fitted to the backboard itself – as always order of operations and ease of use were important considerations in the design of everything) it could not fully seal around the strut bar, but the openings do not jump out at you as an onlooker. Regardless I made sure they were tidy and evenly spaced around the strut bar.

Here’s what the display case looked like at this stage, from the backside; the Hello Kitty duct tape that you’ve already seen in this post and others makes another appearance here. I still don’t remember where it came from but I still haven’t worked through all of it! Anyway, you’ll note that the “shelf” in the trunk of the S15 is not a flat surface, so I had to make up a couple of legs of varying heights to support the case and keep it level – one is shown here. With no bolt holes in the immediate area around the legs I ended up using industrial-strength Velcro to secure them (and hence the case itself) to the car and it is well more than strong enough to keep the entire structure fixed in place. Come the eventual trunk makeover (which I am presently designing) there should be a way to tie this case into some more panels but that’s all for another day…

With the basics of the case prepared it was fully glued and screwed together, ready to be upholstered. All screws were of course countersunk so that once covered in fabric there would be no bumps showing through.

Covered in the same fabric and slid back into place, I was overjoyed with how the display case was coming together especially with the subtle glow from the LEDs reflecting off of the strut bar. But when did those come into the picture, you’re wondering?

This here is the only piece of this entire seat delete assembly that I would consider temporary, and that would be the back wall for the display case. I imagine this will get replaced with a new copy once the trunk gets retrimmed but again, that’s for another day. This first iteration is a simple flat panel that Velcros to the display case (again, ease of disassembly and serviceability were important) and not only sealed off the case so the trunk wouldn’t be visible when looking from inside the car, but also provided a place to mount a small LED strip and its power supply.

With the case more or less ready to go, it was time to put in the window. Black Box Industrial was able to provide some acrylic sheets, one of which I secured to the backboard with more of the industrial-strength Velcro. The acrylic and hardboard – being so thin – would make screws a tricky mounting method not to mention it would be tough to reach them once the panel was bolted into the car (and if I had used hardware for this piece, I wouldn’t want it visible from the front). The Velcro once again was more than strong enough for this application and also left open the possibility for easily switching out the acrylic in the future if I ever wish to change its colour, or need to replace it should it get damaged for any reason.

Acrylic secured in place, and the backboard vacuumed in prep for final installation.

Now it was really coming together and I was getting quite excited at what I was seeing! The trunk’s light being positioned to also illuminate the display case was an unintentional feature but means I can quickly show off the bar to anyone curious without turning on all of the LEDs. On that, the entire lighting setup is contained on that removable back panel (the strip, its wiring, and its dedicated power bank are all secured to it) so it’s extremely easy to service and change out.

At this stage the assembly was nearly there, but there were still some details to address; the pre-existing lower panel still had to be trimmed down a hair (not to mention be reupholstered so it matched) and I wanted to make some trim panels to seal around the lower legs of the cross bar, but first up was to start on the damper access covers.

The assembly of these was fairly straight-forward. I had kept the cutouts from the upper corners of the backboard as they would work to secure these covers in place. The extra thickness of the fabric covering the panel nearly perfectly accounted for the kerf of the saw, so these leftover inserts snugly fit into the openings. I took some scraps of acrylic and cut them to match the general profile of the access holes while enlarging them to cover the seams, and with a small piece of styrene in the middle as a spacer (making up for the width of the fabric on the front face of the backboard so the inserts sat fully in the openings) the covers were glued together and left to dry.

Once cured they were prepped, primed, and then painted in black followed by some matte clear to kill the shine.

One thing I already knew however is that I didn’t want to leave them bare. There was no need for these to be labeled for my own usage (I know what they’re for and which way to spin the knobs based on how I want to adjust the coilovers) but this was an opportunity to add some detail since this entire back seat area serves as the interior’s focal point.

I ran through a small number of fonts before deciding on the one you see here, then cut a number of decals in varying colours and sizes so I could mock them up in real life and see which worked best. In the end I decided to introduce the idea of running different colours side to side for various details on the car, and used pink/Chalk decals for the driver’s side piece with blue/Chalk for the passenger. Ignore the dust here, I remember it being windy that day and anything left near the door got covered in crud immediately.

While the access panels were underway I also quickly made up the covers for around the cross bar’s legs. Various bits of cardboard were cut and assembled to make the shapes before they were transferred over to some hardboard.

Soon after the wooden copies were cut and ready to go, so they were upholstered and left to fully dry. More wind, so more crud blowing in the garage too. Once these were dry some small sections of Velcro were applied to the backsides (and the corresponding areas of the bottom half of the seat delete, once reupholstered) so that these too could be quickly and easily removed without tools, and be secured without visible hardware.

Speaking of, with all of the other pieces being underway or finished at this point the bottom half of the delete was left as the last component to address. With the old fabric removed and some test-fitting/measuring taken care of, a small amount of material was removed from the back edge to make up for the newly-introduced backboard and its upholstery, allowing this assembly to still sit snugly against the floorboard of the car once bolted in place.

You know the drill at this point: pulled out of the car, cleaned up, adhesive applied, and fabric secured in place.

And at last, with everything mounted back in the car (including a small section of upholstery over the exposed hump in the middle of it all) this was the finished product! I was extremely pleased with the setup and the feedback it received this year was absolutely amazing. For a fairly small amount of money all together I now have this amazing display in the back of the S15’s interior and all of the chassis bracing definitely makes itself known from a handling standpoint (not to mention visual).

I could have kept this whole project much simpler overall had I kept the backboard solid (or even gone without Miracle Bars entirely and just built two delete panels) but for the S15 I wanted something crazier. Mustard’s seat delete was intended to look OEM whereas this was intentionally meant to be a bit of a showpiece and get people talking – which it definitely does.

As noted in the post from earlier in the year revealing this entire assembly, the acrylic window into the illuminated display case takes influence from the crazy I.C.E. setups while instead showing off something “functional” rather than heavy audio equipment, but beyond that the entire assembly was approached with functionality, performance, and usability in mind. The bracing substantially tightens up the car, the delete panels then keep the road noise down as compared to running the car gutted as most do with Miracle Bars, and finally the damper access panels allow me to easily and quickly play with suspension settings as the adjustment knobs would otherwise be sealed away thanks to those delete panels.

Before closing though, I will also point out some details that I see as places to refine the back seat area just a touch further:

First up, as I had pointed out on camera, the only truly visible hardware needs a slight update; given I could not order in any fresh Downstar hardware in time for the debut at Driven this year the backboard has a blue washer under each bolt. A few of us are intending to organize a group buy for some Downstar hardware over winter and I will absolutely be grabbing some blue and pink pieces for the delete panels to continue with the theme of each side having its own accent colour. The bolts for the bottom panel are not visible when looking from the outside of the car but they too will be changed out as they’re just hardware store pieces still (though painted black to blend in).

The multi-colour LED strip will ideally be changed out for something much brighter so that I can also have the illumination (somewhat) visible at outdoor events, but the lighting setup will likely need to wait until the trunk updates are underway.

Lastly, I might redo the method of covering the small holes in the side panels which you may have noticed in some of the photos. The top holes are still covered with plastic plugs as shown in this post but I never found any suitable for the lower holes so they have circles of black vinyl over top instead, for now. I have a couple of ideas to explore, regarding those.

Those details and more though are to come a bit later on. As the S15 sits in the garage this winter and those gears in my head start turning again, it’s the trunk that I have my eye on this time around as mentioned. As Mario so eloquently put it, “you have this crazy interior and then the trunk looks like sh!t”. Challenge accepted, Mario – let’s see what I can come up with for that.


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