Thrid Gen Pontiac Firebird Suspension Upgrades - Tightening Up Loose Ends

It's not unusual to hear someone claiming his or her car has "go-kart-like" handling, or someone asking how to achieve this mythical benchmark. Given the go-karts most of us are familiar with don't even have suspension, why would you want this for your daily driver? The obvious answer is because go-karts are a blast, which is in part because they provide direct feedback between driver and machine. If you were to design a go-kart and consider the relationship between noise, vibration, and handling (NVH), there would be no thought given to reducing noise; little to no vibration, and all effort would be placed on handling. Automobile design is quite a bit more demanding in that noise and vibration are of greater concern as the average consumer would much rather give up feedback for comfort.

To reduce noise and vibration, GM provided our Formula with rubber bushings of varying durometer, or hardness, at all suspension interfaces. While the rubber does a fine job of isolation, the joint is not truly free to rotate as rubber is bonded to an internal steel crush sleeve resulting in increasing resistance as the suspension swings through its arc and may reach a point where the sleeve breaks free, resulting in a sudden change in apparent spring rate (in somewhat erratic fashion). In addition to the non-linear resistance at the joints, a rubber bushing allows subtle changes in geometry as it is winds up and deflects. This is not to say they don't work, but they do at the expense of the relationship between the driver and machine, essentially numbing the feedback that makes a go-kart so much fun. In addition to suspension upgrades, we have carefully chosen components that will provide the driver with a high level of feedback.

With the introduction of the 1LE-spec third-generation F-bodies designed for SCCA showroom stock racing, GM increased the durometer of just about every rubber suspension bushing in the platform-they wouldn't have done this if there wasn't a handling benefit. Every interface is important, from motor mounts to sway bar endlinks, when determining how a suspension will perform. While Project Snowball will log plenty of road miles, we are focusing on road course and autocross performance; as such our choice of suspension components will reflect this goal, trading civility for performance. BMR Fabrication's suspension components have increased strength and reduced weight, compared to stock, and eliminate the spongy rubber bushings. Meanwhile, Koni's adjustable struts and shocks will provide a serious upgrade to the Formula's WS6 suspension, all of which will prepare Snowball for upgrades in braking and power that would have seriously stressed the stamped steel suspension parts we have replaced.