There are many reasons to install a roll cage in a vehicle. The most obvious is for safety, the less obvious is the chassis strengthening that goes hand in hand with the installation of a proper race-legal cage. One point that needs to be addressed immediately: a roll cage in a street driven vehicle can do more harm than good. Although some might think the look of having a cage adds eye candy to his/her ride, most compact cars leave very little space for the cage tubes to coexist with the vehicle's occupants - making the occupants quite vulnerable without a helmet. The bottom line: if you choose to do a full race cage, do it in a full race car. I've smacked my head pretty hard against the roll cage at track events, and that's with a helmet on - I can't imagine the world of pain, and spilled brains, without one.
In this article we wanted to illustrate the fabrication and installation of a properly built roll cage. Since the employees at Turbo were fresh out of race cars in need of roll cages, we had to look elsewhere for a donor. In our search we found Steve Sawitz of Laguna Beach, California. Sawitz decided it was time to retire his '03 Subaru WRX from being his daily driver, and instead convert it into his weekend play toy/rally car. All good rally cars need a roll cage, of course, to prevent chassis flex during hard turns. A strengthened chassis allows the driver to get more feedback from the road - key when every millisecond counts on a timed course.
Up for the task of installing a proper roll cage was L-Con Race Car Fabrication and Engineering in Placentia, California. Weighing the pros and cons of different roll cages we settled upon the Gravel Crew cage kit that was designed with rally racing in mind. The kit includes a 1.5-inch-OD (outer diameter) with a .120-wall thickness DOM seamless tubing B-Pillar, 2 A-pillars, and a windshield bar. From the available options, we chose the following: a complete water-jetted floor plate kit with attachment points of no less than 14 places for the '02 to current unibody shell. The kit was designed to work for many race applications and features only four main points - leaving the decision to install additional tubes up to the customer and their racing organization's rules. This particular car was built to run in California Rally Series events. One of the main things that the owner stressed to L-Con was the importance of strengthening the vehicle - as he wants to jump, and jump big.
The project gets underway with the complete disassembly of the interior of the car, trunk, and a good portion of the engine compartment. After the car's interior has been gutted, the car is prepared and further stripped of paint, primer, and body sealant in all the places where tubes will eventually make contact. Now we're ready to begin the installation. We felt the next set of steps is best shown visually, so photos accompany each part of the process.
For the final step in the process, L-Con fabricated custom sheet metal plates; drilled and dimple died them for weight and strength; and then installed them everywhere the cage comes into contact with the shell. The plates are imperative to tie all major points of the cage to major points of the car's chassis. Without plates attaching the upper half of the cage to the chassis, the cage would flex as much as a scary 3/8 of an inch under hard driving.
The end result of installing a high quality roll cage is a whole new car - a car that will perform and last with some proper and effective suspension tuning. Look for this WRX flying down a dirt road or launching off in random industrial parks.
Tools RequiredSafety glasses, welding gloves, leather work gloves; available from local welding supplyMillermatic 350p Mig welder and a Syncrowave 350lx tig welder; available at www.millerweld.com1.5-inch DOM .120 WRX main hoop, A-pillar bars, upper window bar, and .125 mild steel floor plate kit; available at www.l-con.netCrud thug, 90 grinder -- our favorite; available at www.snap-on.com10 mm, 12 mm, 14 mm socketsScrewdriver setTamper proof 8 mm Torx driver1-2-inch collet and 1 box of blue roll lock, cut off wheels with cole, 3.5-inch flap wheels, 3-inch and 1.75-inch hole saw and chuck; available at industrial hardware storesMetal cutting chop sawElectric grinderTubing notcherDrill80 feet 1.5-inch .120 DOM, 40 feet 1.5-inch .095 DOM; available at local metal supply3 lbs 3/32 70s2, 2 lbs 3/32 silica bronze welding rod; available at welding shops20 lbs dry ice; available from local ice cream supply or welding supply store