Lola Indy and ChampCars use conventional unequal length a-arms and pushrod/rocker suspension front and rear. Both the front and rear dampers are mounted on the top for easy access. They work though rockers to control pushrod movement. The uprights are ventilated to allow cooling air from the brake ducts to travel through them and cool the bearings, rotors and calipers. The calipers are eight differential piston, four pad radial mount units by Brembo. Independent braking systems are used for front and rear with a user adjustable bias.
Lola has a unique swaybar arrangement that takes movements in the rockers and transfers them to a vertically mounted roll bar. In cockpit adjustability is provided by a mounting "blade" which is rotated to provide more or less torsional resistance.
Most of the show cars you find have the more aggressive street course wings installed. Almost all of them were last run at Fontana and therefore have super speedway gearboxes and suspension. The super speedway configuration requires positive camber on the left side of the car along with a stager in ride height. Normally, the suspension differences between road course and super speedway consist of rockers, left side pushrods, left front upper and lower a-arms, left rear camber block, and left front camber plate. A lot of teams choose to use the super speedway linear rockers for both speedway and road course running. Lastly, there are numerous options for attaching pickup points, especially in the rear, and for setting the position of the rod end in the pickup point. These options are used to change roll center along with other geometry and are well documented in the chassis manual.
Special care and attention must be paid to the suspension when running these cars. Professional teams crack test all suspension items at least once every two races! Vintage racing is significantly less demanding (slower drivers, no curbs) and thus our cars are done every off season or twelve hours of run time. Our FAA certified propeller shop does a great job of NDT (non-destructive testing) at a very affordable price. Most of the effort is in the disassembly and reassembly of the car. All the suspension bits are painted with black epoxy propeller paint when the cars are first restored. This paint survives on a propeller and thus does a great job on suspension a-arms and wheels. It is worth noting that I have found a good number of cracked uprights and a-arms on cars I have purchased from pro teams. Once the cars have been thoroughly rebuilt, I have yet to find a cracked component nor have I done anything more that clean, check and repack upright bearings.
Dampers are an especially interesting component. Through the end of the 04 season, I had yet to adjust a single damper. All of my tuning was directed at ride height and cambers. My initial thoughts on dampers were to sweep the extremes of all for adjustments on both the front and rear dampers during a test day to learn the affect of each individual change. I also wanted to get a feel for how dampers control springs and chassis movement and thus contacted a friend that has been in racing at all levels for many years. And thus my Alice in Wonderland journey has begun.
The first item on the list was a three hour session sweeping each adjustment on the Ohliens TT44 dampers used on the rear of the 99 Lola. The exercise was designed to teach me that (1) the adjustments are non-linear and (2) exceeding a certain adjustment range can bring about undesired effects. Simply sweeping the adjusters to their extremes on a test day would have been disastrous! One example would be to adjust the low speed compression from 11 clicks from full closed to 9 clicks from full closed to 7 clicks from full closed. You can see from the plot below, that adjustment is linear until you get to 9 beyond which the dampers compression and rebound stacks begin to misbehave. Specifically, hysteresis rears its ugly head and the zero velocity point no longer approaches zero pounds of damping. The change from 11 to 9 clicks (from full closed) has a reasonable affect. The next two click change to 7 does not. The only way to properly understand damper changes is to characterize each adjustors affect on the damping curve and understand the practical limits of adjustment for each function. None of these tasks are particularly hard; they just require patience and attention to detail.
