It has been said that there is nothing new in racing, and today's race cars are just refinements of old technology. Although that's not really true, it is possible that we may have left some old ideas in the barn that warrant reexamination.
Just such a reexamination has happened with a car that's running at the Orange Show Speedway in San Bernardino, California. A racer by the name of Roger Brown is winning the Sportsman track championship in a 25-year-old car with technology of the same age. A quick look at the car reveals some technical suspension aspects you don't see every day.
A Little HistoryA company known as Real Race Cars originally built the car in prototype form in 1975. West Coast Racer Bob Bouchard, who experimented with the rear suspension trying three-link and four-link setups, then owned the car. He used a Panhard bar and a Panhard bar with a roller. What he eventually ended up with was an upside-down wishbone configuration.
The front suspension was (and is) a copy of the Ford setup used by noted car builders Holman and Moody at the time. Originally built as a Sportsman class car, it had a straight-rail design with a complete tube chassis. It had a '69 Camaro body on it. Just after finishing the car, Bouchard passed away, but his car lived on.
The car changed hands and in the late '70s was set up for open competition racing. It changed hands again and became a road-race car, competing at the fabled Riverside, California course. Later, the car won a race at Willow Springs Motorsports Park's road-race course in Rosamond, California. Then it sat for 10 years until Brown's father bought it.
The Front SuspensionBecause the front suspension is copied off of the '65 Ford, it's a so-called "rear-steer" car. The lower strut runs forward and attaches to the frame using a Heim joint instead of stock rubber bushings. It uses the '65 Galaxie spindles with late-'60s screw-in upper and lower Chrysler ball joints. Most of the then-Grand National cars used the Chrysler ball joints because of their mass. Steering linkage is all Ford, and the drag link is beefed up with a couple of brackets added for strength. The idler arm came from Speedway Engineering, and the car has an early 16:1-ratio Corvette steering box.
The lower control arm is stock '65 Ford, and since it's rear-steer suspension, the steering setup is behind the crossmember. In its day, rear steer was popular because it was said to have a cornering advantage. It was thought that tight racetracks were easier to drive with the rear-steer configuration.
In an explanation of rear steer, it's possible to understand how it works by explaining it in terms of geometry. By drawing a line from the lower ball joint where the spindle pivots through where the tie rod mounts on the right side, and drawing a similar line on the left side, both of those lines should intersect at the center of the rearend housing. That will give you zero Ackermann, which is not possible on a front-steer car. This is true because the tie rod would be out into the tire. In effect, a rear-steer configuration provides for a pushing of the tire from the tie rod while a front steer is being pulled.
Today, virtually everyone uses front steer, and the debate on which is better centers on pushing or pulling the tire. Probably the real reason the racing community has changed from rear-steer suspension is the forward-facing strut. When there is heavy front-end damage, the front attachment point is susceptible to damage. This destroys the steering geometry. With front-steer cars, the strut runs back behind the wheel, out of harms way.
The other interesting feature of the car's front suspension is that it is adjustable for ovals and road racing. There are two holes in the frame where the lower control arm mounts. They are side by side, 31/44 inch apart. When racing on a short track, the lower control arms mount in the right-side holes, looking from the rear of the car. To go road racing, both the control arms are moved to the left holes.
Since most road races are mainly righthand turns, this will add some weight to the right side of the car. This adjustment doesn't offset the chassis; it offsets the steering a little bit. You have to realign the suspension, which is generally reversing the camber and caster settings. The other change would be to change the springs and shocks that would be appropriate for that track.
The RearendThe rear suspension is truly unique. It is an upside-down three-link with a wishbone underneath the rearend. The upper links are equal length and mount above the rearend axle tubes. The right side link angles a little bit uphill, so when the car is in the corner, it levels out. The left side is level when the driver is in the car. That way, it also is level in the corner.
The wishbone attaches to the bottom of the pumpkin by a 111/44-inch Heim. It's 211/42 inches wide and lets the rearend float up and down.
The rearend tracks straight because of the two links that angle out from the center of the pumpkin. They are securely mounted to the chassis about 3 feet apart. With the wishbone underneath the rearend, the rear roll center is very low. It eliminates a lot of the body roll and weight transfer in the turns.
With this system, there is no rearend movement in the turns, and it does not rotate laterally in the corner or roll over. The only body movement is front to rear. When you get off the gas, the car squats even before the brakes are applied. When you get on the gas, you can see a little weight transfer to the rear. With this setup, the car is stable and driveable. The driver is not getting the sensation of everything rolling while the upside down wishbone acts very much like an old truck-arm suspension. The system also lets the rearend float while limiting body roll.
There is no adjustment for rear roll center. Changes can be made only where the upper links mount to the chassis. The link angles may be changed to provide more or less antisquat.
In the end, old technology may be worth a second look, especially if it makes the car easier to drive. Some times, it's possible to trick yourself with all the new fangled contraptions available today. This car appears to prove that an old dog can teach new tricks.
Driver's ImpressionRoger Brown is a design engineer for Nissan, and upon seeing the car for the first time, he was doubtful it would run well simply because he thought a computer did not design the suspension. The fact is, this suspension was designed on a very early computer at Chaffey College in Alta Loma, California.
After more thought, Brown became interested, and one of the selling points for the car was that it had zero camber change during roll. This is because of the long lower control arm. In addition, with the single control arm, all the forces are fed to the chassis, limiting roll and making the car very stable. It also has zero caster change and zero track change. All of this adds up to a suspension that has zero tire scrub on the front end. So he took the car to the track. One modification that was made to the car was the addition of a perimeter frame to make it NASCAR-legal.
"The car is easy to drive," says second year racer Brown. "The front-end geometry is awesome. The car is awesome on tire wear. I never wear out the right front. I will wear out the right rear first. The front has a very stable feel. It never wanders. You always know what the car is going to do. It never surprises you."
He further explained why the car works so well. "The goal is to make the spindle follow the path of the lower A-arm more closely than the top A-arm. That gives you less scrub. On most spindles, the snout welds onto the side of it. There is usually some distance between the lower ball joint and snout, maybe a couple of inches. On this spindle, the lower ball joint and the snout are real close to each other. This added to the fact that the car has real long lower control arms, allowing the car to have no scrub throughout the full camber curve."
Brown also talked about the rear suspension. He explains, "The advantage of the wishbone suspension is it takes out the side-to-side movement of the rearend-that normally takes place with a J-bar or Panhard bar. If the car has body roll, the Panhard bar tends to make the rearend move left and right. This car doesn't do that because it rolls about the wishbone axis. So there is no rearend side-to-side movement. That is the best thing.
"The bad thing is, you can't adjust the rear roll center. You have to adjust somewhere else on the car. The rear roll center stays constant. But all in all, I can't believe the car turns as well as it does."