Although it feels a little blasphemous to say, Hondas, just like every car, are not perfect. One major drawback to our little econo-box racers is their uni-body construction. In lieu of a more solid frame, they've got sheet metal panels and subframes holding everything together. This is good for your mom when she goes to buy a Civic for shuttling your kid sister to school, because it keeps the price tag affordable. This is bad, on the other hand, for you because unless those seams are welded, your unibody car will likely have significant chassis flex.
For the super noobs, don't mistake chassis flex for body roll. Body roll is how far your car leans in a turn. Chassis flex is usually not visible to the driver. It is the twisting of the body of the car itself. Why does it matter? Because chassis flex is an uncontrollable variable in your dampening system. The amount of give in your chassis has to be factored into your suspension setup to get real figures when calculating suspension characteristics. As a very crude example, if your front driver's side coil is a 500lb spring and your chassis flexes enough to take up 50lbs of that (by flexing .1 inch per 1 inch of coil compression), you've only really got 450lbs of spring to work with.
To make up for losses in the stock chassis, aftermarket manufacturers have been producing chassis reinforcements in the form of strut tower bars and other bracing for years. While these types of bracing originated as crude and poorly designed (remember the ovalized, bent, extruded aluminum pieces of crap we used to pay so much for?), the field of chassis bracing has evolved considerably.
A shining example of the new technology coming forth in the suspension world is the 5Zigen Pro Racer DC5 bracing kit. These steel bars are hand TIG welded and chrome plated and have brackets that are similarly welded and powdercoated black. With so many different components in the kit (front/rear tower, rear lower, rear mid section, c-pillar, and floor bar), there were enough boxes strewn about the office that we were thinking of getting a Christmas tree. With the D3 Designs front double-X brace already in place on not only this car, but the RSX Challenge car we built, we knew what to expect from tightening up the RSX chassis. The D3 brace alone annihilated understeer, the only regret being ground clearance. After installing the Pro Racer kit, Bob was nothing but positively effusive.
"It was like driving a smaller car. The RSX is a lot more collected through turns, a much more precise machine. She also seems less likely to break traction up front. As a whole, the kit delivers."
Here's how Bob's Saturday went installing the myriad of bracing.
Tooling AroundWhat to Keep Handy When Installing ProRacer DC5 Brace BarsAdjustable wrench13 and 17mm open-end wrenches 6 and 8mm hex keys 12 (deep), 14 (deep), and 19mm sockets, extensions, and a ratchet Slotted screwdriver Floor jack and jack stands Panel popper Utility knife or heavy scissors