Race Tips - Performance Newsletter            

from Auto-Ware

June 2012 

Shop Tips -  Homemade Test Probe


led     test probe

 Here is one of my best tools when trying to

 track down electrical gremlins in race cars,

 and I made it for less than the cost of gas

                                                   driving to my local electrical part store.


You will need to pick up, at least, a red/green Bicolor-LED and a couple 1200 ohm resistors. I sneaked into my wife's sewing cabinet and borrowed a large needle. Next, I scrounged through the garage and found 2 alligator clips, a piece of two conductor 22 awg wire (most any light wire will work), shrink tube or electrical tape and a clicker style ball point pen. Source your bits and pieces as you dare and then follow the instructions below to make your own test probe.


First, solder a resistor to the end of one wire and use a short piece of shrink tube to cover the body of the resistor, solder joint and back to overlap the wire's insulation. Repeat the process for the second resistor and wire.


Next, twist the exposed ends of the two resistors together and solder them to the short leg of the LED. On the long leg of the LED, solder a short wire connecting the LED to the needle (this wire should be just the right length so the needle will stick out one end of the pen and the LED out the other end of the pen). Now, use a piece of shrink tube (or tape) to cover the solder joint of the needle back to the LED bulb.


Disassemble your donor pen, dump the guts, and drill a small hole in the pen for the wires to exit the barrel. Next, feed the free end of the wires into the center of the pen and out through the hole you just drilled. Carefully feed the needle and LED into the pen as you pull the free end of the wires and screw the pen back together for the final fit. I selected a pen that had a rubber finger grip that I slid over the wire exiting the pen to keep it secure. Lastly, put the alligator clips on the free ends of the wires and a dab of super glue on the pen at the needle to hold it secure.


Connect the alligator clips to the battery and you are ready to test. As you are probing, when the LED is green, you have a positive (or hot) wire. If the LED is red then you have a negative (or ground) connection. If the LED is not illuminated, then you have an "open short."


Race Tips -  Another Data Trick!


Now that we live in the digital age we should not forget some of the old time techniques or tricks. One old racer trick was the way gauges would be twisted in the dash so the needles would all be pointing straight up when readings were ideal. That way a quick glance at the dash and you immediately knew if everything was okay or if a reading was high or low, just by seeing the needle's position.


I like to use many of those visual tricks with my data acquisition. One simple straight analogy is how you scale strip charts, measure graphs and time/distance plots. Just select the appropriate scale for the Y axis so the squiggly data line will be plotted in the middle of the graph when the sensor reading is at the ideal value.


Now you can quickly glance at a screen full of data and if the plotted lines are in the middle of the graph things are good. Likewise, you immediately see if something is low or high (like oil pressure and water temp) without actually studying the graph and the numbers on the side of the graph.



This is one good example of how data can be analyzed in 10 seconds or less. However, there are hundreds of other ways to use a basic data system to analyze vehicle performance and driver skill. With a little training, data systems become very easy to understand. At that point, the benefit of having data far exceeds anything you can bolt on to your racecar. 


Our webinars have helped many racers achieve new personal best times and win races. Classes start the week of July 16th, so don't miss out! Sign up now before it is too late. Click HERE for more info and to sign up. Space is limited at each webinar series so I can give individual attention to participants.



Equation of the Month - Average Lap Speed

When we are at the race track, most of us have a stopwatch in our pocket or at least within quick reach. We time our cars but don't always have a chance to catch all the competition. Typically, that's not a problem because the officials have a list of all competitors, but often they are listed with speed in MPH and not lap times.


You can use this month's equation to quickly convert the average lap speed back to time or use the second equation to convert your time to lap speed.


T = LD x 3600 / MPH   T is lap time in seconds, LD is lap distance in miles and MPH is the average lap speed in miles per hour.


Or to go the other direction MPH = LD x 3600 / T


Please pass this newsletter on to your friends and tell them to drop me an email so they can get the Race Tips Newsletter, too.  You can always go to our web site Auto-ware.com and see the old newsletters.
John Block