CHASSIS BUILD


Before construction begins on a race car like this, we study the rules,  establish the design parameters, and set goals for the build.  In this case we knew we had to strip the car to a bare tub.  The bare tub, after spending about 100 hours to strip, now weighs 680 pounds.  From previous experience building GS class cars we estimated that about 140 pounds would be added in cage construction.  To make weight the finished tub with cage and paint needed to weigh 600 pounds.

We spent about 80 hours cutting all unnecessary metal from the tub and cut about 450 holes in the tub to save weight.

The rules and safety dictate the cage contain certain elements that are primarily for driver safety.  The mandated tubing is bent and temporarily installed in the car.  We use string to help visualize the tube layout.

All tubing below the “belt line” is designed to stiffen the chassis.  All tubing is bent on our rotary draw bender after it is designed on the computer.  All the tubes are coped with a horizontal coping mill and all fits are “light tight” for TIG welding.

The Grand Am rules encourage quite a bit of tubing for driver safety.  Because we intended that all structural loads are carried below the belt line no silly filler panels are welded at the “A” or “B” pillars. Many holes are cut in the upper parts of the tub to save weight.

The finished tub is sent out to be powder coated.  We like light colors for the tub as it makes servicing the car much easier when completed.

The finished fully caged ready to assemble chassis weighs 604 pounds and is over four times as stiff as the stock chassis.  It has taken about 250 man hours to get to this point.