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Barracuda Weight Reduction - Lighten Up!Our Bracket Racer Goes On A Diet From the September, 2007 issue of Mopar Muscle By Dave Young Photography by Dave Young
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After adding the weight of... After adding the weight of a rollcage, frame connectors, and other safety equipment to our project Barracuda, we needed to lighten it up. Follow along as we show you some economical ways to shave pounds from your street or bracket car by removing unnecessary accessories, installing polycarbonate windows, and replacing steel parts with fiberglass. It has long been known that a car's power-to-weight ratio is a good indicator of how a vehicle will perform at the track. As a standard rule of thumb in drag racing, a one-hundred-pound decrease in weight will shave approximately 1/10 of one second from a car's elapsed time in the quarter-mile. Since a tenth of a second is approximately equal to one car length, it makes sense to make your car as light as possible if performance is your goal. Because performance is definitely the goal of our Barracuda project car, and since we added the weight of a rollcage, frame connectors, and torque boxes, we'll show you how we lightened it back up by removing unnecessary equipment, replacing the glass windows with lightweight polycarbonate, and adding fiberglass body components.  The glass installed in most...  The glass installed in most cars of this era was thick and heavy. The rear window of our fastback model is particularly weighty, so it will be removed along with the rest of our car's glass.  One of the first steps to...  One of the first steps to reducing our vehicles weight was to remove all the items that won't be used in a race car. Items such as the fuel tank, heater box, side window regulators, and windshield wiper assemblies don't seem to weigh that much individually, but when added together, their weight is significant.  When we were finished gutting...  When we were finished gutting our car, this is what we had removed. Some items, such as the fuel tank, will be replaced by lightweight aftermarket parts. Others, like the heater box and rear seats, will be left out. Since we removed our glass... Since we removed our glass windows and window regulators, we only need the inner structure of the door to support the door release handle. The rest of the metal can be cut out to save weight. Again, the weight reduction is minimal, but when combined with everything else it does make a difference. Lightening a race car, or street car for that matter, always involves walking the line between safety, structural integrity, and weight. When building a car for the track like we are, a rollcage is mandated by both the NHRA sanctioning body and common sense. If we want to be safe and run on sanctioned tracks, we must install a legal rollcage in our car. Since we're installing a fairly powerful big-block in our A-body, we deemed it necessary to add frame connectors and torque boxes as well. With all this extra steel, we'd be hard pressed to get the weight of our Barracuda below its factory shipping weight, but we can fairly easily negate the weight we added by lightening the remainder of the car. A good place to start this lightening process is by removing any unneeded equipment from the vehicle. Since our Barracuda will only see time at the track, we won't need the luxuries of windshield wipers or a heater, so those items and their associated hardware will be removed. Additionally, we'll be removing the glass side windows, so the window regulators and a significant portion of the inner door metal can be cut away. Since we'll be using a lightweight fuel cell located in the trunk, the heavy factory fuel tank will also be discarded. If you really want to get carried away, lightening holes can be drilled in any nonstructural parts of the car. This process is labor intensive, and is really only justifiable when building a truly dedicated race car that needs to be as light as possible. Since our car is a bracket racer, we won't go to this extreme. Since it doesn't cost anything... Since it doesn't cost anything but time, we spent a while scraping the undercoating off our car. Again, weight reduction seems insignificant, but every ounce helps. Replacing some of the steel outer body panels with fiberglass parts is another way we'll shave pounds from our bracket racer. Remember though, some replacement fiberglass body parts are flimsy and poorly made. While these types of replacement panels will save weight, chances are they won't fit well, and they certainly won't last through the abuses of drag racing. Knowing that we needed to find good-quality fiberglass, we called our friends at AAR Quality Fiberglass and ordered a hood, trunk lid, and both bumpers for our Barracuda. The AAR parts are exceptionally well built, with reinforcing braces molded into the underside. The finish of the AAR parts is also outstanding. the parts come ready for final sanding and paint; there is no trimming or bodywork required. By ordering a pin-on hood and decklid, we'll be able to save additional weight by eliminating the hood, trunk hinges, and latching mechanisms. The final way we'll save weight from our car is to replace all the glass windows with lightweight polycarbonate material. The glass, especially the rear window of our fastback, is very heavy, which makes this one of the best techniques to save weight. Even if you've never fabricated and installed polycarbonate windows, you can do the job easily with tools you already have in your shop. The material is available from any home-improvement store and is easy to handle, cutting easily with a jigsaw. By using the factory glass as templates, you can replace all the glass in your race car in a weekend, shaving significant weight in the process.  After cutting and gutting...  After cutting and gutting our car to reduce weight, we added torque boxes, frame connectors, and a 12-point rollcage. While the added weight of these components isn't great for elapsed times, it is mandatory for the safety and longevity of our race car.  We replaced our trunk lid...  We replaced our trunk lid and both front and rear bumpers with AAR fiberglass components, as well. Again, the weight savings by changing these components alone is not dramatic, but in conjunction with our other modifications we reduced the weight of our vehicle by several hundred pounds.  Fiberglass body components,...  Fiberglass body components, such as the hood shown here, are a great way to shave a few pounds from your car. We love the products of AAR Quality Fiberglass in Cocoa, Florida. These pieces need no bodywork, just a quick scuffing with a Scotch-Brite pad, and they're ready for paint. Also, don't forget about the most important type of weight: reciprocating weight. A reduction in reciprocating weight can have an exponential effect, freeing horsepower to propel the car forward. Lightweight pistons, rods, and valvetrain components all help free up horsepower in the engine, and lightweight driveline components require less power to turn, thereby putting more power to the rear wheels. Speaking of wheels, lightweight rolling stock is a benefit to any race or street car. While we didn't weigh the items we removed from our car individually, we did weigh the car when it was completed and in race trim. On the scales, without a driver but otherwise ready to race, our Barracuda weighed 2,878 pounds. Knowing that a factory '67 Barracuda's shipping weight was approximately 2,900 pounds, we basically negated the 200 pounds of rollcage and 50 pounds of frame connectors and torque boxes, getting our car back down to its factory weight. While this doesn't sound like much, remember that every hundred pounds equals a tenth of a second, or about a car length, which could mean the difference between a win and a loss. Additionally, by reducing the weight of our car, the load on the engine and drivetrain is reduced, thereby lengthening the service life of our components.  By using pins to keep the...  By using pins to keep the hood and trunk in place, we eliminated the hood and trunk hinges, as well as the latches, for another incremental reduction in weight.  The first step to replacing...  The first step to replacing the windows with lightweight polycarbonate is to remove the original glass. Most original rubber gaskets are dry and brittle, so you'll need to cut them with a razor knife to get the windows out.  Using a gasket scraper, we...  Using a gasket scraper, we cleaned any remaining sealer and pieces of the rubber window gasket from the frame. We can now prime the window frames in preparation for our new lightweight windows.  While premade polycarbonate...  While premade polycarbonate windows are available for most popular Mopar race cars, we decided to save a few bucks by cutting ours out ourselves. Sheets of clear polycarbonate can be purchased from most home-improvement warehouses. Be sure to get a minimum of 11/48-inch-thick material as outlined by the NHRA rules.  To reproduce our Barracuda's...  To reproduce our Barracuda's side windows, we used the original glass units and traced around them on our polycarbonate sheet. A jigsaw is then used to cut them out.  For a nice border, cut approximately...  For a nice border, cut approximately 1 to 2 inches of the backing material from the back side of the window. This area will be painted on the inside, providing a border around the window and a more finished appearance.  The polycarbonate material...  The polycarbonate material will need to be scuffed with 400-grit Scotch-Brite, then can be painted with black spray paint. Be sure to do the inside surface, not the outside.  To fasten the lower edge of...  To fasten the lower edge of our new windows to the doors, we riveted a piece of aluminum L-channel to the top, inner surface of the door frame. The window will ride in the forward track and be screwed to the L-channel with countersunk screws.  After tracing the shape of...  After tracing the shape of the front and rear glass onto the polycarbonate sheet, be sure to add a minimum of 1 inch around the entire perimeter of these windows. Since the factory glass is held in with a rubber gasket, the glass is actually smaller than the opening. By adding an inch around the edge, our polycarbonate window will be slightly larger than the opening in the car and can be sanded along the edges for a perfect fit.  Once fitted, we'll use No....  Once fitted, we'll use No. ten countersunk screws to hold our front and rear windows in place. Keeping the protective paper on the polycarbonate during this step prevents damage to the new windows in case you get a little out of control with the drill.  To seal the new front and...  To seal the new front and rear windows, and to prevent the thinner polycarbonate from being too recessed into the window frame, we line the frame with self-adhesive weatherstripping. This can also be purchased at your local auto parts or home-improvement store.  To make room for our countersunk...  To make room for our countersunk machine screws, the holes are again drilled using a countersink bit. We're using countersunk screws because they look better and are more aerodynamic.  Using a drill stop, like the...  Using a drill stop, like the one shown here, will help prevent damage to the polycarbonate when drilling attaching holes.  With the windows installed...  With the windows installed and all the fasteners in place, the protective paper layer can be removed, revealing our new polycarbonate windows underneath.  Don't overlook the obvious...  Don't overlook the obvious when it comes to saving weight. By utilizing aluminum heads, water pump, and the water-pump housing, we shaved more than 50 pounds from the front of our already nose-heavy, big-block A-Body.  Lightweight wheels and tires...  Lightweight wheels and tires can dramatically improve performance as they constitute reciprocating, as well as static, weight. While our budget for this build didn't allow for extremely light wheels, such as the ones shown here, we did score a deal on a set of steel Cragars with aluminum centers that are a little lighter than factory wheels.  All told, our weight-reduction...  All told, our weight-reduction program lightened our car by several hundred pounds. While you may not want to go to the extremes that we did to lose weight, every pound counts. Stay tuned to future issues to find out if our efforts resulted in achieving our goal of 10-second timeslips.
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