For many a grassroots bracket racer on a working man’s budget, performance is an unnecessary but desirable luxury; after all, everyone wants to go quicker and faster, whether it improves their chances of winning or not. It’s just part of the gearhead DNA.
After you’ve spent the money on the engine and the drivetrain, one of the most obvious undertakings of any entry-level racers’ checklist is reducing the overall weight of the car. This is particularly the case for the thousands of racers out there with all-steel body cars, who are pushing a sled of lead down the strip. Although there are other factors at work, performance is dictated by a weight-to-horsepower formula: the lighter it is, the quicker it will accelerate and in turn the quicker it will reach the finish line. But that same token, a lighter car will react at the launch better and also come to a halt with less effort.
One can pursue this in many ways, from aftermarket composite doors, lightweight composite front ends or deck lids, and even bolt-on chrome-moly front chassis clips. But only one weight reduction avenue will not only shed some pounds but also add to the safety of your race car, and that’s your windows.
Optic Armor Performance Windows has made quite a name for itself in drag racing circles since bursting onto the scene a few years ago, and for good reason. Optic Armor produces its windows from a polycarbonate, a highly durable thermoplastic polymer that’s easily thermoformed and shaped. While the material is impressively impact-resistant, it has a fairly low scratch-resistance in its raw form. Manufacturers like Optic Armor, however, add a hard coating during the manufacturing phase that shores that up, giving their windows exceptional resistance to scratches — so much so, that their windows will take a week of constant application of steel wool on a wiper in their trade show display booth and still look as good as new at the end.
The optical clarity of Optic Armor's windows is so good, you can hardly tell if the windows are up or down.
“Our stuff is the best of both worlds, between regular polycarbonate and glass. You get a really highly scratch-resistant, shatter-resistant, lightweight window. With glass, it’s heavy and it breaks, but it doesn’t scratch as easily, while regular polycarbonate is shatter-resistant and light, but it scratches really easily. But with our coating, it gives you the best of both worlds,” explains Optic Armor’s Jim Dunham.
Optic Armor keeps the secret sauce of their windows tightly guarded, but Dunham shares that their coating is flow-coated and then baked on to the windows. Optic Armor purchases the polycarbonate in raw sheets and completes the rest of the process in-house at their Missouri facility, cutting out the windows, thermoforming the shapes, and applying the coating to arrive at the final product.
And that final product, it’s super-strong.
Optic Armor has performed certified impact testing on their windows that have shown them to be 250 times stronger than a typical OEM glass window, but at the same time, they’re also very lightweight. How light? Well, we decided to put that to the test, by installing a set of their oversized windows on a common bracket car, to illustrate the differences on the scale.
The car, a 1972 Chevrolet Monte Carlo that runs in the 6.6-second range in the 1/8-mile, weighed in at 3,323 pounds before we began, with a full steel body and all of the original glass, minus the OEM roll-up mechanism in the quarter windows. We went with a 1/4-inch windshield (Part No. CHE681-4), a 3/16-inch rear window (Part No. CHE686-3), 3/16-inch door windows (Part Nos. CHE682-3 and CHE683-3), along with a pair of universal 3/16-inch quarter windows (UNI002-3).
To keep the car utilitarian on a hot day at the track, and potentially even street-driveable, we decided to install the door windows in a roll-up configuration, which added to the time and complexity of the project but was certainly worth the work in the end.
Our first order of business was to create a template of the original glass. This would provide us a template for cutting the polycarbonate, along with the measurements needed for fabricating our bracket to mount the window to the regulator.
If you’re going to tackle a project, you might as well tackle it head-on, and so we focused our attention first on the driver’s side and passenger door windows, which would involve the most extensive fabrication work of the entire undertaking. Because we wanted to retain full roll-up functionality, some custom work was going to be necessary to make it all work seamlessly.
After calculating the necessary measurements, we clamped our chromoly tubing to the OEM glass and tack-welded everything in place.
As you know, the factory glass is typically mounted directly to the window regulator, and the Monte Carlo is no different. Our Optic Armor window, however, was a little shorter in height than the factory glass, and so we set about measuring for and fabricating a bracket out of chromoly to extend the gap between the bottom edge of the window and the mounting point to the regulator. Because the window can be pivoted fore and aft and up and down on the regulator mount to get the right fit on the door, our bracket had to be close but not 100 percent precision.
We utilized the OEM glass to provide the template for the brackets on each side, which runs the length of the window, with nine bolts each holding it in place.
Once complete with our hardware, we turned our attention to the new windows. As you’ll see throughout this process, we took extra caution to protect the window though liberal use of painter’s tape. Optic Armor ships their windows with plastic wrap to protect them during handling and to prevent cracks when cutting, but you can never be too safe.
As with each of our windows, we utilized a thin sheet of cardboard to trace the shape of the original glass, which was then transferred onto the polycarbonate. By using blue painter’s tape, we had a nice canvas to trace the outline on to ensure a clean, perfect cut.
After tracing our template onto the window, we were ready to make the final cut.
Once the window was cut, we mocked up the bracket on the window and drilled out the mounting tab holes. After that, it was time to paint the bracket, install it onto the window along with all of the hardware, and shimmy it down into the doorframe. Because of the adjustability of the window on the regulator, we spent some time closing the door and re-adjusting to get the perfect fit against the A-pillar and the window seals. Once we got the quarter windows in, we again had to inspect both side to ensure the entire puzzle fit well together will no noticeable gaps.
After cutting the window out, we clamped our bracket in place and drilled each of the mounting holes. Because the window could be re-positioned on the regulator fore and aft, we didn't have to be spot-on-the-money with this, but we had to get it fairly close. Once the window is in the door, we can adjust as necessary.
Depending on the vehicle in question and the intended speed of the car, upper window latches may be necessary to keep the window from bowing out at the juncture of the A-pillar and the roof at speed, so that’s a point to keep in mind. In our initial on-track testing, we found the windows to pull away and present a small but noticeable gap downtrack, but some additional adjustment of the window positioning cured that.
(Left) An up-close look at the window and bracket as we installed it onto the window regulator.
Door window weight (pair): glass 28 lbs., polycarbonate w/hardware 12 lbs (-16 lbs) Total weight removed: -16 lbs
Our door glass weight, including the hardware.
We began the windshield work by tracing the OEM glass onto our cardboard template, which we’d later transfer onto the polycarbonate.
When going in the direction of aftermarket windows, one is presented with a pair of choices: they can either go the legitimate race car look and flush-mount, or they can stick with the stock look. In our case, we wanted to retain as much of the factory appearance as possible, and that included keeping the chrome window trim that gives the Monte Carlo such character.
A close-up of the mounting blocks we welded to the body flange. On the front windshield, these ranged in spacing from 4.5 to 6 inches. Optic Armor advises 4-inch spacing, but because we were doubling-up with weatherstripping, we could get away with slightly wider-spaced bolts and maintain integrity.
We already knew that, from the factory, the car utilized 5/16-inch thick weatherstripping, so we began with that as the basis for our measurements on the placement of the window within the flange.
After we cut our template out for the windshield, we laid wooden rods across the bend in the windshield to ensure proper fitment all the way across and top to bottom.
After cutting out the windshield with a jigsaw, we set it in place on the car and, beginning in the middle, pre-drilled each of the bolt holes through the blocks on the flange and installed temporary Cleco fasteners (left) to hold the window in place. Working from the center out ensures the window lies flat with no 'bunching' that might occur if you worked from the outside in to the center. Once finished, we took the window back out and fully drilled and tapped each hole.
It should be noted that the front and rear windows can be mounted using glued weatherstripping, bolts, or both. Optic Armor’s recommendations vary depending on the application, taking into account such factors as horsepower (which might play a role in potential tireshake) and top speed. We were advised that weatherstripping would likely be sufficient for our Monte Carlo, but just for extra peace of mind, we opted to double-up and both bolt and glue the windshield in.
Here, we're preparing the weatherstrip for installation. Each piece had to be measured out and cut fairly accurately to fit between the blocks.
Before final installation, we drilled out countersinks using an 82-degree countersink bit — 82 degrees is the standard angle for flathead screws.
To do this, we welded in a series of 5/8-inch tall steel blocks around the flange to serve as the platform for the window to rest on. Optic Armor advises to maintain 4-inch centers between bolts when mounting the window with that method, but because the bolts were in addition to the weatherstrip moreso than the sole anchoring mechanism, ours varied between 4 and 5.5-inches around the perimeter of the window.
We used 5/8-inch depth weatherstrip, cut and placed in between the mounting blocks. Once complete, we spread a thin strip of sealant across the gap on each block to keep water out.
After cutting the windshield, we set it in place on the car and began drilling for the mounting bolt holes one-by-one, starting at the center and working out to the edges. Doing this ensures that the window is laying completely flat and not “bunched” at any point. Optic Armor suggests maintaining a 1/4-inch gap between the windows edge and the bolt centers around the perimeter, to stave off stress cracks from too little material between the bolt and the edge.
After pre-drilling all of our bolt holes, we removed the windshield, tapped each of the holes, and then drilled our countersinks in the window itself. With this, we were ready for final installation.
Using the aforementioned 5/16-inch weatherstrip, we cut exacting length pieces to fit in between the blocks all the way around the window and laid those in place, and finished it off by spreading a layer of weather sealant across the blocks themselves to create a constant barrier all the way around the perimeter to keep the elements out. Once ready, we dropped the windshield in, installed all of the bolts, and then re-mounted our chrome trim via the factory clips in the flange.
The weights of the respective windshields. Because of the nature (and nasty mess) of well-aged weatherstripping, we weren't able to account for those in the weights, perhaps shifting our overall weight accuracy by a few ounces in one direction or the other.
The process for the rear window largely mimicked that of the windshield, with the primary difference coming down to the depth of the weatherstripping, the mounting blocks, and the need to create additional notches in the window edges for the mounting clips for the trim pieces.
The original rear glass in the car was 3/16-inches thick and used a 5/16-inch weatherstrip, but because we went with a slightly thinner 3/16-inch window from Optic Armor, we had to make up the difference in height by going to a 3/8-inch block and weatherstrip to get the window to the same position in relation to the body.
We pre-marked all of the mounting bolt locations around the perimeter of the rear window (and the windshield) on the painters tape on the body.
(Left) Optic Armor advises 1/4-inch spacing from the bolt centers to the edge of the glass to maintain strength and avoid cracking.
The final rear window weights.
The template for the quarter window is a near exacting copy of the original glass, although we did away with the lower holes used for the roll-up window function and went with a custom bracket design.
Unlike our door windows, we had no intention of retaining the roll-up window mechanism — which was good, because the wheel tubs had already rendered them unusable anyway. However, like the door windows, fabrication work was necessary to create a mounting bracket to securely bolt the window to the body in place of the window regulator that had existed previously. To do this, we had to figure out both the distance from the window to the mounting location, and the angle of the window.
The hard work of the quarter windows was in the measurement and fabrication of the mounting bracket. With that all complete, installation was nothing more than working the assembly into the body and installing the bolts.
The mounting location itself was the easy part — we simply mocked the window up in place and marked the distance inward to the inner fender panel, where the two bolt holes that would hold the window in place exist. On the opposite end of our bracket, however, we needed to mount a series of tabs to bolt to the window itself, and these needed to be welded on at a precise angle or otherwise the window would stick out from the body rather than laying flat against the roll of the body like it should. Admittedly, we kind of made an educated guess at this angle and nailed it — 85 degrees.
We replaced the two chunks of steel shown at bottom with the lightweight mounting bracket seen above, helping to shave off a couple of additional pounds.
Finishing out the quarter window process, we drilled and mounted the OEM trim and rubber seal, as well as a new inner plate for the seal, which is necessary since this car doesn’t have a B-pillar.
This inner body panel and the two original mounting holes serve as the anchor for our quarter windows. To build our bracket, we mocked the window in place and measured the distance from the bolt centers out to the window. Because this window isn’t semi-adjustable like the door windows, we had to have this accurate.
The final weights of the quarter window, including all of the hardware. As you can see, we took a good chunk of steel out of the car by removing the glass.
Finished weight: 3,265 lbs. (-58 lbs.) **The weight discrepancy between the window difference and the final car weight falls inside the +/- 5 lb. accuracy of our scales.
With the factory trim installed, the Optic Armor windows look the part as well as nicely as the OEM windows once did....only lighter and far more clear.
Out initial impressions of the windows are nothing but positive. First, they’re impressively strong and stiff, and we’d fully expect that even in an impact that caused the windows to break free, it would still be in one piece. There’s no flex and no give … on par with the glass we removed. The optical clarity, likewise, is substantially better than the factory glass — so good that in an environment void of sun glare, you’d have a hard time discerning if the windows were up or down. The weight, of course, speaks for itself. It’s not the most significant weight reduction investment you can make, but it’s part of the larger puzzle, and as we mentioned earlier, it’s the one avenue that you can shed weight and improve other key factors — strength, safety, optical clarity — as well.