The Science of Straight

Drag racing is one of most basic yet most exciting forms of motorsport.The concept is simple to understand and virtually anyone can getinvolved.

It doesn't matter if you're driving a stock street car, aslightly modified boulevard bruiser, or a purpose-built drag racemachine--there's a class for everyone. Fortunately, many Fordproducts--especially the late-model Mustang--lend themselves to the dragracing arena. And if you modify your machine to run quicker elapsedtimes with a greater trap speed, you'll quickly realize you must alsomodify the chassis and suspension to get the power to the ground.

There's a science to applying horsepower. To do it you'll needtraction--and lots of it. But you can't sacrifice control or stabilityin the process. You'll learn early on that the quickest way to thefinish line is a straight line. You'll also learn those who make wildruns are not the good drivers; they're the ones who end up with slowe.t.'s. Even worse, they sometimes end up in the wall. Maximizingperformance takes a basic understanding of chassis and suspension, andwith that knowledge you'll be on the fast track to low e.t.'s.

The Chassis
When it comes to building a quick, reliable, and safe Mustang,you should begin with the chassis. As it's the foundation, it must besturdy.

Late-model Mustangs utilize a unibody chassis (also called theframe). A unibody chassis is built from a thick, sheetmetal floorpanwith most of the body structure welded to the floor. This creates arigid platform to which you can mount the suspension components. Itdiffers from a full-frame chassis (which resembles a ladder) that usesframerails supported with cross bracing to which a body and suspensionare bolted.

There are many benefits to unibody construction, includinglighter weight and reduced construction costs. It also allows for thefloor of the vehicle to be lower. These factors make unibody cars greatfor racing, but there are some important modifications that should bedone to prepare a unibody car.

First and foremost, you must strengthenthe chassis. When it comes to Mustangs, the unibody structure was notoriginally designed to handle the torque loads of a racing engine orslick tires. Simply stated, when the power is increased or slick tiresare added, you increase the load on the suspension components, thepick-up (or attachment) points, and the actual unibody structure.

It istherefore critical to install bracing that will increase the overallrigidity of the unibody and the pick-up points. If this isn't done--anddone properly--the unibody will flex, the suspension pick-up points maymove, and the suspension can't work as designed. The car will beunpredictable and it may handle poorly.

Because of this, we also nowknow to add a set of frame connectors. These are neces-sary because theytie together the front and rear subframes of the vehicle, and theyrein-force the unibody chassis structure.

Next on the list for anyserious racer should be a rollbar or rollcage. This type of structurewill add crash protection for the driver and strength to the unibody. Itis important to have the structure tie in to critical points in the carthat will enhance the strength. Simply welding it to the floorpan is notas good as having it welded to the stronger bracing points, namely themain floorboard crossmember, the rocker panels, and the rear shocktowers. With the engine applying torque to the K-member and thesuspension prying on the floor in the back, it becomes increasinglyimportant to also add kicker bars connecting to the torque boxes wherethe suspension parts mount.