Last minute assembly

[Ballistic Racing]

Ok so our pack race is next Friday & we weigh & turn in the cars on Wednesday. my son's car is graphite & I've preped the wheels, polished the axles, do I wait till the last minute to apply the pledge & install the axles or will they perform the same if I do it today & have the car ready to go?

Also, I'm running in the unlimited class for the dads.
Oil is aloud & max weight is 9 oz. I decided to run 5oz. & of coarse oil. Some of the other dads think I'm crazy & at a BIG disadvantage... I think they're wrong! What do you guys think?

We're running those wheels with the raised tread surface I posted a few weeks ago. I trued them on my comm lathe. The bores were something to speak of, .096 until the last 1/32" on the inner bore side, a little lip still there so I reamed them to size & they polished up pretty good. I'll post picks of the cars before the race. This will be my son's first race as a tiger scout, he's pretty excited!

 

[GravityX]

Applying the Pledge now won't hurt the prep.

As for the unlimited, I think I would bump the weight up to at least to 6 ounces. There is a point of diminishing returns and I want to say that after 6 ounces you don't gain any more speed, please correct me if I haven't remembered this correctly guys. Are you using bearings in this class?

 

[Ballistic Racing]

Bearings are allowed but didn't want to go that extreme. I'm sure I'll be the only one using oil.
The car is finished & no more room for added weight so, we'll just let'r ride! Rears are canted, three wheeler, one raised & going to go 4" in 4' for steer on both cars. COG is about 5/8" on both cars. I might go with a little less steer on my car... Just for fun!

 

[BulldogRacing]

good luck man! keep us posted on the results

 

[bracketracer]

Applying the Pledge now won't hurt the prep.

As for the unlimited, I think I would bump the weight up to at least to 6 ounces. There is a point of diminishing returns and I want to say that after 6 ounces you don't gain any more speed, please correct me if I haven't remembered this correctly guys. Are you using bearings in this class?

Paul, I'm sure 6oz is faster than 5 since my SR's are quicker to the bottom of the hill than my SS cars. (Fair comparison since they run the same weight wheels) But a bearing car would beat both of them on the flat. Much lower loss per foot.
I seem to recall the tipping point for max weight was closer to 9 oz. I would have maxed out the weight and run thick bearing razors.

 

[quadad]

Last I remember hearing from 5Kids was that one of his kids did a Science Project on the subject and more is simply better !

 

[5KidsRacing]

Below is an old post from the PWDR, but these are the results that Quadad is speaking about...

My oldest Son decided to do his 6th grade science fair project on the effects on weight vs. speed with a pinewood derby car. Last night we built and ran the car and I would like to share the results. The car was a railrider and had a set of wheels I had cut for my Pure Stock car and had 91 axles. The car was prepped with Legend and Jig-A-Loo and ran oil. The car ran very well and very straight. The car weighed almost exactly 2 ounces with no weight, but we had to start with some weight in the rear otherwise the car would tip onto the guide pin. I have a bunch of ½ ounce brass pins so we started with 2 pins so the car weighed 3 ounces and we ran the car 5 times and recorded the results. We added 2 more pins each time and repeated the experiment up to 10 ounces. Since the car kept going faster we ran a few more tests at 11, 12, 13 & 14 ounces to see what happened.

Here is the car:

Here are the results:

3 ounces:
3.125
3.126
3.118
3.120
3.120

4 ounces:
3.068
3.069
3.067
3.064
3.067

5 ounces:
3.028
3.028
3.029
3.031
3.031

6 ounces:
3.008
3.007
3.007
3.008
3.008

7 ounces:
2.993
2.992
2.993
2.993
2.991

8 ounces:
2.981
2.982
2.981
2.981
2.981

9 ounces:
2.972
2.973
2.973
2.973
2.971

10 ounces:
2.967
2.968
2.968
2.967
2.967

11 ounces:
2.964
2.962
2.963

12 ounces:
2.962
2.960
2.960

13 ounces:
2.958
2.959
2.958

14 ounces:
2.956
2.953
2.952

I had read on another board a couple years ago that after about 9 ounces any additional weight wouldn’t add to the cars speed. I don’t believe that now. Maybe with graphite there is a maximum effective weight, but with oil it seems you can go much heavier and still gain speed.

 

[5KidsRacing]

A short video of us running the car can at 14 ounces be found here:

http://5kidsracing.webs.com/apps/videos/videos/show/16126523-science-fair-experiment

 

[5KidsRacing]

 

[Ballistic Racing]

What a great science project! Looks like I might be in trouble. I stayed with the 5 oz, my som's car got most of the tungsten cubes (lack of planning on my part) so ended up pouring lead into the remaining weight pocket space. I saw all the competition at the weigh in, most of the cars were very bulky with lead all over the place just to get to the 9 oz. max. I still think I have a chance as my car is very stream line, used everything I learned from this site, oil process & all so we'll see. Race is tonight! Thanks everyone for the input, we'll just have to see if my building skills can out perform science!

 

[Crash Enburn]

Similar to 5Kids, I helped a boy in our Pack do a similar weight experiment. Running graphite, the speed topped out at 6 ounces. You have a *very* solid chance running a tuned car at 5 oz. on oil. Then again, adding another ounce (or more) to the outside of your car is pretty simple.

 

[BulldogRacing]

very very cool project! Thank you for sharing!

 

[Ballistic Racing]

Well, it was a good night of racing. My son took fastest in his den & pack winner! The races were run so fast that I hardly had any time to take some pics. The track was an older 42' Best Track. My son's fastest time was a 3.000, (oooh so close to a sub 3!) avg time out of 4 runs was 3.008 I checked the site (rentmytrack.com) & he has the fastest time this year to date... Way cool!
My car (oil prepped, 5 oz) ran just a hair faster at a 2.986, with an avg time with 4 runs 2.993. I took 1st in the unlimited but there were a couple of close ones with those 9 oz cars! Whew! They ran all the cars together randomly but both our cars never ran together, would have been fun to see how close a race between a 3.0 & 2.9!
I'll try took load some pics tomorrow. Thanks for all your help... Now on to districts, new cars with the works