This is a test. It is only a test, so please do not adjust your race car, yet. The following is a significant test and involves certain discoveries and logic. It's not significant just because I wrote it or because it's in this magazine. Its significance stands on its own. If you read this and don't come away with a new outlook about bump technology, I urge you to re-read it, the message is in there.
Stan Flis, machinist and fabricator...
Stan Flis, machinist and fabricator for Spirit of Daytona Racing, which runs a Chevrolet Corvette Daytona Prototype, machines the ends on our aluminum sleeves that will be used to space up to the bellows springs. The ends need to be exactly 90 degrees to the sides for proper seating to the carbon-fiber parts.
It's no secret that I haven't been in favor of the soft spring setups using bump rubbers as springs, let alone the ultra-large antisway bars in conjunction with those soft springs. I have already explained exactly why I have been opposed to that, what those setups do to a good race car and how, even now, many well qualified racers are struggling with them.
That being said, there may be a solution to the problematic use of bumpstops and this is the purpose of this test. We intend to show that we can achieve the low and superior attitude for our race cars while not having to give up handling and mechanical grip. Now, if this works the way we think, we can have our aero and handling too.
History and Development of Bump Technology
All of this soft spring and running on bump rubbers stuff started with the Cup teams and involved a "looking down a tunnel" mentality that was only concerned with enhancing aero efficiency for both reduced drag and increased downforce. And all of that is good, to a point.
What happened, as I heard it, was that indeed the cars got faster, stuck to the track better, and handled like crap. The drivers complained, but were told to basically shut up and drive. There were and still are, certain compromises associated with going faster this way. And the older drivers had big problems driving those cars. Dale Sr. credited Dale Jr. with helping him overcome his confusion about these setups and to trust that the car would stay on the racetrack despite all of the bouncing around and weird attitude.
Meanwhile, it all got back to the short track guys and the thinking was, if it's good for the Cup cars, maybe we should be doing it. And so, the big bar and soft spring, or as some prefer to call it, soft spring and big bar, setups took hold and now nearly everyone thinks they need to go this route in order to be successful. And there is little that anyone can do to dissuade them from this direction.
This is the configuration...
This is the configuration when assembled. This was exactly what I had envisioned when I first saw these bellows springs on display at PRI in Orlando at the Hyperco booth. Kelly Falls and Mark Campbell explained to me how these new springs work and the benefits of reduced weight, better linearity, and reduced tendency to bow. These springs were tested with many repeat cycles of operation without failure.
Installing the coilover assembly...
Installing the coilover assembly the first time told us that we needed clearance between the aluminum sleeve and the top edge of the big spring cup. So we cut square holes in the sleeves to eliminate the contact. We also replaced the old style upper control arms with new, larger radius Coleman Racing upper arms.
Here we see the right coilover...
Here we see the right coilover assembly and it had much more room for adjustment and lowering. The new Coleman large radius upper control arms provided needed spacing for our bellows springs. These uppers come with low friction ball joints and caster adjustable slotted and slugged shafts.
Problems Associated With BBSS
Right away, certain teams went faster and won. These were admittedly some of the more well-financed teams who could afford to gamble and who had the resources to test and buy the components needed to make these setups work.
What is still happening is that these setups are very difficult to tune to various racetracks and even at the same track when conditions change slightly. Big-name racers like Freddie Query and Jay Fogleman, two guys that I know personally and whom I have talked to about this, are still searching for ways to accurately predict just how to set up for the soft spring setups.
Both of these gentlemen will tell you unequivocally that these setups are necessary and will provide more success than either soft conventional or conventional setups. And I for one will not argue with this level of experience and talent.
So, the question is, how can we make these setups more manageable and comparatively easy for the average racer to achieve? This question has more or less haunted me and intrigued me for some time now. Then I attended the PRI show in Orlando this past December and a light went off.
The reason why the BBSS setups are so much of a problem lies in the way the bump rubbers perform. The characteristic of the bump rubber is such that it has a spring rate and that rate is variable. It changes as the rubber is compressed and the rate rises in a non-linear way.
That means that in the first 0.100-inch, the rate may increase by 100 ppi (pounds of spring rate per inch of compression). In the second 0.100-inch the rate may increase by 200 ppi, and in the next 0.100-inch of travel it might go up 400 ppi and so on. At some point in the compression, and it's not very far, maybe a half inch or so, the rate increases dramatically and just beyond that it goes basically solid.
Much time and expense is spent right now, by many teams including the aforementioned two, trying to determine just how much spring rate, or loading, is on those bump rubbers at a particular track in each turn. And by using that information it is hoped, and I repeat the word hoped, that a conclusion and method can be established that will help them set up for any track. As far as I know, that hasn't happened, but I will say that each is getting much better at it and they are accumulating more and more information.