K.I.S.S.-no, not the rock group:
The concept of keep it simple, STU...
I talk to a lot of racers. In doing that, I get a sense of how they do things; how what they do helps them be successful, or not; and what works for most teams. The approach is everything. And what seems to work most of the time is keeping your approach simple. A lot of you readers get that point, but many don't.
There are, simply, certain critical issues you need to address for any race car, be it a Street Stock or Formula 1 car. These issues involve alignment, spring setup balance, weight distribution, and roll/moment center management. It is always the same issues that will either come together to help you be successful or that when mismanaged, will keep you at the back of the pack.
What many teams do is overcomplicate the issues. They over shock the car, over spring it (can you say stiff right rear spring?), they over soften it, over rear steer it, or they just plain over think it. The most successful racers I've met are the ones who work into a very good setup and then stay with that setup. And it's usually more toward the conventional side rather than exotic.
Example: I worked with a team one year and we won both the track championship and the regional championship with 14 wins. Two years later, the team couldn't get a Top 5 finish. I visited one Saturday and looked over the setup sheet. It had changed from the successful setup that had won races to what-ever. I said, "We're going back to what worked two years ago," and we did. The team won the race that night in dominating fashion.
Simply stated, if you find what works, stay with it. Keep it simple. Just because everyone is experimenting doesn't mean you have to. When you get the four tires working and happy on your car, work on driver development, tire selection and management, engine tuning, and so on, but leave the setup alone.
In most racing, having a comfortable car for the driver to drive is most important. Now push the limits with the car. Don't let a good setup put the driver to sleep. Motivate him/her to push harder.
We got wrecked in the first race of a twin 100-lapper show one night and put the car back to close to where it was before the wreck, before the second race. The driver was pissed off and in the final race, where he had to start from the rear, he drove up through the field and drove away from the leader at the end of the race. We realized that the car had even more in it than we had seen in the past and his extra "passion" brought it out.
There is a certain car owner whose car wins almost all of the time here in Florida when a good driver sits in the seat. He runs a more conventional setup and standard shocks-6s on the front and 5s on the rear. It is simply a very balanced setup with all of the peripheral issues worked out such as Ackermann, rear steer, and moment centers. And the setup doesn't change race to race, year to year. It just keeps on winning.
Can you do the same? As Sarah Palin would say, "You betcha." We tell you how to make all four tires work and how to tell when that is happening. We tell you how to adjust for rear steer and all of the other aspects of alignment. You have the tools, you just need to apply them and go racing. And most of all-apply and use the K.I.S.S. principle
If you have comments or questions about this or anything racing related, send them to my email address: firstname.lastname@example.org, or mail can be sent to Circle Track, Senior Tech Editor, 9036 Brittany Way, Tampa, FL 33619.
Too Many Rules
Too Many Rules
I certainly enjoyed your article and Circle Track April issue, pg. 8. To keep my background brief, my wife and I got into racing late in life, but thoroughly enjoyed our last years of racing Outlaw Late Models in Michigan, Indiana, and Ohio. I agree, wholeheartedly, with your column regarding too many rules, which are diminishing the racing as we know it today.
I also am displeased with the way track owners/promoters are trying to slow down the cars and "level the playing field" (as they put it). The mechanics and engineering are what attracted me to the sport in the first place. The Kalamazoo Speedway now instituting a new 7,700 rpm chip limit, i.e. Senneker Rule, is a case in point. Another is a track requiring the old fashioned all-steel brakes.
Now being in my 70s with these "level the playing field" rules, I now am losing interest in the sport and I think it's time for us to exit it. Being from the old school, yes you must have rules, but when you "level the playing fields" by making the leaders slow down, it's extremely disappointing. Thank you again for your fine article.
The promoters must be careful when instituting rules that reduce the cost of racing. Yes, we do need to make racing less expensive, but not limit ingenuity at the same time. When you have repeat winners, it's usually because they have figured it out better than the competition, or they are cheating. In case of the later, catch them and you'll enhance the playing field and cause more to want to race. If the reason is the former, then everyone will have to catch up, it's always been the rule of racing.
The newer series where two or three classes of race cars are allowed to run together helps create diversity. In a recent race here in Florida, the top two cars were running a built motor and a sealed motor. If we can get back to allowing racers to run different equipment and equalizing by weight, we might just bring the sport back to the glory days of 30-car fields.
We'll keep hammering home the idea that rules restrictions intended to please all, will only confuse and frustrate too many racers who will decide to quit the sport like you are planning on doing. That's not good for anybody. Allowing for freedom in design and application is just what we need to get the excitement back into short track racing.
Zero Roll Angle
I am curious to know if it's possible to achieve a zero-degree roll angle without coil binding or using bumpstops? If so what would the quality of the springs have to be? How would one prove that one had achieved the proper result? I'm certain you know that coil binding and the use of bumpstops will not be allowed in the NASCAR LMSC division this year.
Another interesting approach is big spring, big bar a (1.75- to 2.0-inch bar and 500-pound LF and 450-pound RF) then reducing cross bite, which will cause the car to be more free in the corner, with the thought it keeps the car from binding as it turns. A spring rate of 400/600 pounds on the RR and the height of the track bar help the car to turn. The LR spring is 125/150 pounds.
Since we are traveling the front of the car (3 inches shock travel), at which time the lower arms are set to be at the max radius from mechanical center, increasing the tread width from static frame height. By doing this the angles on idler and pitman have to be changed to achieve proper bump. Uppers will probably be 24 degrees LF 20/22 degrees RF, no antidive in left upper and 0.25-degree antidive right upper, no anti-dive on either lower arm. Now the question is, why do we need a drop snout configuration any longer?
You can achieve a zero-roll angle, I just wrote an article on that subject a few issues ago so look back and read. But, why would you have as a goal a zero-roll angle? On most short tracks, aero is not a factor in speed. So keeping the car flat to the track is of no value, especially if doing so makes the car unstable or unpredictable and inconsistent, which in many cases it does.
You describe a method to achieve a low roll angle and even a zero-roll depending on how you arrange your springs. A more sensible setup would maintain enough spring rate to keep the car on the springs in the turns while allowing a lower profile which does help with creating a lower center of gravity and less load transfer.
The drop snout design was perfect for the older and stiffer spring setups where we rolled more and dove less. This design allowed a consistent moment center design and very little camber change at the right front wheel. Now with setups that dive more and roll less, we don't need, or can use, the dropped snouts and resulting higher upper control arm angles.
Moment center control is still a desire and we have to live with the camber change issues. Rules changes that limit and/or disallow running on coil bind or bumpstops are a good way to go. It's sad when the track officials and promoters are smarter than the racers. In this case, I think they are.
IMCA Mod Bar Lengths
I have a couple of questions. First of all, we race IMCA Modifieds and I would like to know about four-bar lengths. I've heard that there are guys running bar lengths as short as 10 inches; we are currently running 14 inches on the lowers and 16 inches on the uppers. We are running the four-bar on both sides. Is there an advantage to the shorter bar and what length upper bars do you use?
Running shorter bar lengths allows more cockpit space for the driver for taller drivers. You can move the 'cage back several inches while keeping the same wheelbase. Geometrically, shorter bars react more to vertical motion in changes to front and rear motion of the rear end.
Both short and long lengths can be made to steer the same within certain ranges and be made to create zero rear steer also within a range of vertical motion. I suggest that you support the car and move each rear wheel vertically so determine rear steer characteristics. Measure horizontally from a fixed point to each wheel rim across the center of the wheel and when you move the wheel vertically, note the change in fore and aft movement of the wheel.
Plan out how your wheels will move in the turns and recreate that movement. Then you will know if and how much rear steer you have. If it's not what you want, make changes to the bar angles to create what you desire. The tendency now is for less rear steer and a more straight ahead attitude going through the turns.
Dirt LM Body
Thanks for a great magazine. We read Circle Track religiously. I was reading an old article titled "Dirt Late Model Panels-Hang Tight" by Jeff Huneycutt. I was wondering if you could steer me toward an article that I missed or a company that would sell me the patterns for the panels?
We are pretty handy and have the equipment to make the panels ourselves but do not have a pattern. We are moving to the Dirt Late Model for the 2010 season so I don't have an existing one to copy. Any advice would be greatly appreciated.
Most teams will buy a new body and then make their own templates if they intend to cut their own panels in the future. Some special tools will be needed to create beads and bent edges for radiuses. A good, long sheetmetal brake is also a good idea. And don't forget a pneumatic rivet gun, it will pay for itself many times over. All of these items can be purchased at any race parts outlet store.
Metric Part Numbers
On the metric Monte Carlo, to get the moment center where it needs to be, what exact spindles, A-arms, ball joints, and other modifications do you guys recommend? Any part numbers and manufacturers would be most helpful. I am new to dirt racing, and am building a new car. I subscribe to your magazine and read all the articles relating to metric Montes, but a lot of it is over my head tech-wise.
I would like to buy exact parts you suggest and put on the car, then have caster, camber, toe, and bump set so it handles better. Then I can go get some track time and start learning how to actually drive a car that is set up correctly. The learning curve would be much shorter I think if the car is set up correctly and I don't have to fight an ill-handling car from the get go. I'm 42 and this is just a hobby for me. You only live once, I say. I really enjoy your mag. Thanks for any help!
That is why they call it the Hobby Stock division. I can't tell you exact part numbers for your car, but I can tell you that I heard recently that any AMC spindle off a two-wheel-drive AMC car is useful because it is taller and adjustable for height. One racer has scrounged around the junkyards to find all of these he can in his area.
As for design, we can tell you that you must try to remount your upper control arms so that they have more angle in them, and inside chassis mounts lower than the ball joints. This helps provide a roll/moment center that is more central to the car and does not move very much.
I don't think there are any parts that will make your frontend perfect and some manipulation is necessary to create the best toe, bumpsteer, Ackermann, and cambers as well as caster settings. Heat up that torch and get to work. The Hobby part of the description means you'll be spending quality time in the garage getting that puppy built and set up correctly. And most racers enjoy that time as much or more than track time.
Setups and Roll Angles
I have raced Late Models in the past and have recently had to park my car so that I can concentrate on my education. I'm now setting up/crew chiefing my little brother's LLM car. We have been fairly successful at running a BBSS setup by learning which settings/spring rates, through trial and error, work best with our selection of tracks.
I just read your article about bumpstops/coil binding in the latest issue. We now run pretty much the same front spring/shock/sway bar setup on the front and adjust our rear to neutralize the handling of the race car. Your article provides some specific roll angle statistics.
Is there a computer program to calculate roll angles separately front and rear? If I get my front roll angle to essentially be the additive inverse of the rear roll angle will this be a good starting point to try to go from? I know your programs are good programs. You have been working on them for a while.
I remember when I was about 10 years old going to one of your Chassis R&D seminars at the Piedmont Racing Expo in Roxboro, NC. I just want to know if it will do what I want it to do with respect to this issue. Thanks for sharing your wealth of knowledge.
By reading the article, you know that you can even achieve a zero-roll angle, although we don't recommend that as a goal. You are doing the right thing with the way you match the rear roll to the front. The front is very hard to change once you select your springs and sway bar, so we go to the rear to move the Panhard bar up and down and change the spring split (difference between the left and right springs in rate) to match the roll angles front to rear.
I'm impressed with your memory. I used to do select seminars around the Southeast in past years. The company, Chassis R&D, does sell software that calculates the front and rear roll angles. Yes, I own that company and have owned it since long before my CT days. But now my wife runs it and I have always strayed away from promoting those products in this magazine. If a racer finds his/her way to those programs, fine. It's called free choice.
Most of what I know stems from my working with teams to generate setups. Certain tools can teach us a lot about how certain components affect the setup and to what degree. I remember when I first used a geometry software program where I could change the arm angles and lengths by just typing in new ones. I immediately saw tendencies and trends I could never have imagined.