The Process of Speed

Secrets, tips, tools, design considerations, materials, the "science" behind it all, and other topics related to building the cars and semi-trucks.
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race#67
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The Process of Speed

Post by race#67 »

As you may know I am setting up a 42' Best Track for my pack. One of the liberties I am taking in the process of doing all the work is a test program to show the kids the 'science' behind what they do to their cars. I hope to employ this into a speed workshop at the Pack since we now have a a track we can use for it.
We decided to take a stock kit and run it, then incrementally do all of the tricks to see how each one impacts the speed.
We are racing it against our fastest car from last year (Control), for a visual reference of how each process improves the speed. We have all learned plenty already!

I will start with the fun part, the chart of what we have done so far. Series 1 is the control. Series 2 is the car going from out of the box to modified racer.
On the left vertical is average time per run. The Horizontal axis is the progression of modifications.
Image
Last edited by race#67 on Sat Jan 02, 2016 10:24 am, edited 3 times in total.
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race#67
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Re: The Process of Speed

Post by race#67 »

The tests were run with a two car heat in GPRM, each running once on each lane for a total accumulated time over four runs.

The series 2 car was drilled on a block similar to the commercially available ones. 3 degrees of negative camber in the rear, zero camber on the fronts, right front is the dominant, left front lifted. This allows for fairly consistent variables when pulling and replacing axles after any wheel or axle mods.

The series 1 control car was which raced on a 42' best track we borrowed for our pack race last year. It averaged 2.970 on that track. Clearly they had a steeper start section than we do or something, as that same car is now running 3.1's. I know people say not to pay attention to track to track times, now I see why. For reference the track I am testing on has a 27.1 degree start section.

Here is the key to the test conditions:
Test Number, Control Total, Control Average, Test Total, Test Average, Notes
Condition 1, 12.5623, 3.140575, 18.9007, 4.725175, Stock kit, drilled with drilling block, Revell axles and wheels. 2.605 grams each.
Condition 2, 12.5619, 3.140475, 16.7122, 4.17805, Same as above, weighted to 5 oz, COM 2" ahead of rear axle
Condition 3, 12.601, 3.15025, 13.1036, 3.2759, Same as above, added Max-V graphite
Condition 4, 12.627, 3.15675, 13.073, 3.26825, Same as above, adjusting steer each run to remove wobble
Condition 5, 12.5162, 3.12905, 12.9076, 3.2269, Same as above, consistent 3" steer over 4'. Graphited Control car
Condition 6, 12.5398, 3.13495, 12.689, 3.17225, Same as above Car cutout to wedge, re-weighted to 5 oz, COM 5/8" ahead of rear axle
Condition 7, 12.508, 3.127, 12.4274, 3.10685, Same as above, axles polished with Max-V kit, Diamond polished, and wheel bores polished
Condition 8 12.5466, 3.13665, 12.4398, 3.10995, Same as above, no change
Condition 9 12.5134, 3.12835, 12.3177, 3.079425, Swapped wheels to wheels that have been trued to .0005 runout, 2.45 grams each.
Last edited by race#67 on Sat Jan 02, 2016 9:49 am, edited 2 times in total.
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race#67
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Re: The Process of Speed

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Condition 9 is not a legal condition for our Pack. Those are kit USA wheels my brother trued on a lathe to a runout measured at .0005 or less. This process lightened them as well to a still 'legal' 2.45 grams, but clearly lighter than the stock wheel which are around 2.6 grams each. Our rules so no turning on a lathe.

We need to do another test of USA kit wheels stock out of the box compared to the Revells. The Revells form the test are anywhere from .005 to .008 runout. I have a set of USA BSA wheels that run about .003 to .004. Still need to try those. I really hope they close the gap shown between condition 8 and condition 9.

So based on the above and rules that say BSA axles and wheels only (kit or Revell), what other things are worth trying? I am planning on grooving some axles, and curious about wheel bore treatments such as waxing. All that has been done to these is the bores polished with Micro-Gloss.
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Noskills
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Re: The Process of Speed

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Pretty cool stuff.
Thanks for sharing.
Noskills
"Nunchuk skills... bowhunting skills... pinewood derby skills... Girls only want boyfriends who have great skills!"
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