Siberia Racing
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Reverse Engineering H.O. Style
Bob Colleran

This article was originally written by Bob Colleran.  Bob used to own the unlimited class. He developed the vertical rail carbon fiber chassis car that dominated the unlimited class for several years. Bob was ultra competitive in every class and was an outstanding driver, builder and spokes person for HO racing. While most of us do not have access to some of the tools mentioned here we all can learn from a master who has studied the elite car and come up with some truths. Here are some thoughts on Reverse Engineering H.O. Style from one who knows.

Many of us in H.O. Racing encounter the wonderful dilemma of having that one awesome elite car and most of the time no matter how hard we try we can't build another car that will measure up to the "super car". This can and does apply to almost every Class of racing. What is it about that car that separates it from all the others? In this article we will explore the possibilities some obvious others that maybe you haven't thought of.

In the obvious category - Maybe this car fits your driving style or the limits of your driving ability. For example maybe if the car had more top end or torque you would get yourself into trouble by dumping more often- less dumps- more laps "super car". With the best cars that I've had it seemed that the car would sometimes "save me" and actually stay on when I felt I had pushed it into a corner to hard, there by creating a bigger margin of error beyond what it takes to win the race or pursue the track record for that class.

Ballistic Armature - Superior in top end but not out of the driving control range. In Boxstock, Superstock, H.O.P.RA. Super G modified classes where parts sorting is the key to victory an elite armature can sometimes be almost the sole reason for the elite cars. If you can gain 1-2 feet on any significant straight it is almost impossible for other drivers to overcome. Now you must be able to attribute the speed to the arm not to factors which would decrease your handling such as weak down force magnets, too high of set-up or too stiff of tire or heavy pick-up shoe tension all of which would adversely affect your handling. If your cars handling is equal to or greater than the rest of the field and you have the ballistic arm only your driving (mental errors) or bad racing luck will defeat the "super car". Just a note regarding finding an elite arm in stock part chassis. This example will show how "cheaters" can drive up the cost of racing for everyone. I also understand how parts availability is a factor. In Green Bay where I have raced weekly for a couple of years now we have focused on building elite Life-Like Boxstock and Superstockers. I believe we have the formula pretty well worked out and have came up with some of the top cars in the nation. Putting the handling to a certain level isn't that hard to do, getting ballistic speed to go along with it separates the elite from the merely good. We figure we will find in the non-soldered tab arms approximately 1 out of 100 will be an elite arm, at $3 per arm we were running a $300 arm in a Boxstock and Superstock car, is this crazy? To have an elite car isn't cheap. The situation was better when the soldered arms were legal because you could get 1 or 2 out of 20 that would be elite arms, so really we're now looking for "freak" parts in making a "super car". The dewinders caused the cost of racing to escalate. What is the answer? I'm not sure if allowing dewinding to 5.9 ohm is the answer, but it creates an interesting aftermarket, but we all know ohms is not the only factor. Balance, comm trueness, degree of advance all play a role. I know I would rather pay $10-$20 for an arm that is assuredly fast than to sort through a hundred or more. Matching the speed of the arm to the handling is what really matters. $300 for a Stock Motor?  An interesting discussion on why "Hot Stock" motors should be allowed.

Super Magnets - Again we're looking at freak parts, again a significant percent above the average. Getting magnets within a certain elite range does matter. There are ways to work around this somewhat with different rail and track types, but all other things being equal better magnets, better handling and motor performance with the emphasis on balance.

Chassis - This is rarely the key factor but with what I'll cover later can be significant. The chassis is important in that it holds everything in a certain relationship with each other. Manufacturing tolerances are usually so liberal with stock type cars made of plastic that we're again looking for that "freak" one or type that gives us a good chance to set-up a superior functioning system. This is why we find the idea of opening up the bushing and wearing in a certain amount of flex in the cars creates a better condition for the drive train-loose and free being the holy grail. Comm/brush alignment and tension must be within elite range or top end will never develop.

Building Set-up and Driving - Now we can get into what I believe are a couple of not so obvious reasons why a particular car is considered elite and can we apply reverse engineering to a degree to help our other cars improve? In H.O. racing there are 3 major areas of concern Building, Set-up and Driving. In my opinion very few racers are good at all three. Good at one or two out of three is very common. The key here is that in order to win races you do not have to be good at all three personally, but you can acquire all three through a combination of money, getting help from others, and helping yourself. Driving skill I feel is the most important if your cars are competitive. No amount of good driving can make up for a car that isn't within a certain level of contention. One way of telling whether or not your driving is up to snuff is to give your car to the track record holder or points leader in your club and see what times they turn with your car. If you are more than l tenth of a second per 40 feet of track slower your driving needs to improve significantly. Now here is a great opportunity for you to gauge your cars competitiveness. If the top racers say things like, I would race the car, this is there, or do your want to sell this car you know your building and set-up is competitive. If they say this is way off from being competitive, you should do set-up changes or rebuilding lies ahead. This is the perfect time to ask for set-up help or building advice. If the car is just a little bit off, concentrate on set-up adjustments. I would hope that your club has a spirit of shared knowledge that exists, if not its up to you to start it.

Learning From an Elite Car - Now I'm assuming that you have that l good competitive elite car in your box. How and what can we learn from it? What follows is something that very few people in racing are aware of, I discovered this about 13 years ago, try testing and trying to find what was different about my top cars compared to my average or good cars. Why did my top cars seem to have superior handling which resulted in better lap times and a bigger margin of error when driving in actual races? I first noticed this ratio when after winning a $500 unlimited race I took the car and lift tested to figure out the ratio of front end down force to rear end down force on a straight piece of plastic track. The method was somewhat crude but gave me consistent and relative readings that I further refined. I know that a car interacts on the curve differently than on the straight but the ratio of front end down force to rear end down force seems to carry over. What I found was that if you can keep an approximately 2/3rds rear to l/3rd front down force ratio it creates superior handling. It actually in all superior cars was 35% front to 65% rear + or - 3%. I tested this by attaching a weak spring fish scale to the front axle and lining until it released then doing the same to the rear axle, I tried it on other classes with the same results. When I took my "out of alignment ratio" cars and got them into correct ratio lap times went down and handling improved.

Using a more sophisticated but expensive method would be ideal. Pressure pads are available which could, when mounted on the surface of a set-up track give more accurate and reliable readings to refine the ratio. A minimum of 2 would be needed with the capability of reading down force ranges through all classes of cars. Last I checked cost is approximately $300 each or about the cost of an elite Superstock arm. Compatible electronic readout equipment would probably push cost of a set-up to about $1000.

In racing the interaction of the magnets with the rails is the overwhelming handling factor besides tires. On a road course balance left and right side should be even, back and front should stay 2/3rds to 1/3rd I found a method for correcting out of balance left and right sides with a gauss meter. Now reading the meter directly on the magnet tells us the potential for setting the cars up with 2 identical fronts and 2 identical rears. In an ideal world we would have, even magnets, even rear axle height, even front axle height no variables in magnet retainment and no chassis variable or wear. But then in H.O. racing no true evenness exists so what the relationship between the magnets and rail is, is the primary factor in improving your set-up. A number of racers, most notably Norm Gardner of Sluggos have discovered or come upon through trail and error, that to maximize a cars handling capability requires almost always 4 different sizes of tires. I was able to significantly improve the set-up of all type of cars using the following methods. First I removed the plastic from the back of a set-up track exposing both rails from the bottom. Some custom set-up tracks may have the rails already exposed. Next using a Applied Magnetics gauss meter with the axial probe I would take a reading in the right rear, right front, left rear and left front areas through the bottom of the rail so I could see what the rail was feeling in terms of gauss in each area, then by changing heights and or compound until the left right balance and front rear ratio was achieved I was able to dial the car in and balance it in relation to the rails.

Try it, I think you'll like the results, reverse engineering H.O. Style

Bob Colleran

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