Build Advice

[BradleyP50]

My son and I have competed in our Pack's Pinewood Derby race for the last two years and placed first. Our time has been approximately 3.2 seconds Our first car focused on a wedge design with a tungsten skull weight. We put the center of mass 1" in front of the rear axles, polished the axles, trued the wheels, removed the outer step, and bent the axles to create a rail rider setup.



We prepared a car for last year's district race with the same methods, but routed pockets in the car to get tungsten cubes behind the axles. We didn't do much better time wise with this car, and didn't place in the district race.



This year's Pinewood Derby car for the Pack race was based on last year's district car and took first place again



I think our goal is to get a 3 second car. What improvements would you guys recommend to our build methods?

I have purchased a drill jig from TRE to work on alignment and have plans to build a tuning board. I need to find a test track in the DFW area to run our cars. Our pack only sets up a portion of the track the night before so it is difficult to make modifications before race day. Any help or advice is much appreciated.

 

[bryan]

A quick upgrade would be to cover the bottom pockets with clear plastic tape. Can you run oil?

 

[Castoro Racing]

My son and I have competed in our Pack's Pinewood Derby race for the last two years and placed first. Our time has been approximately 3.2 seconds Our first car focused on a wedge design with a tungsten skull weight. We put the center of mass 1" in front of the rear axles, polished the axles, trued the wheels, removed the outer step, and bent the axles to create a rail rider setup.



We prepared a car for last year's district race with the same methods, but routed pockets in the car to get tungsten cubes behind the axles. We didn't do much better time wise with this car, and didn't place in the district race.



This year's Pinewood Derby car for the Pack race was based on last year's district car and took first place again



I think our goal is to get a 3 second car. What improvements would you guys recommend to our build methods?

I have purchased a drill jig from TRE to work on alignment and have plans to build a tuning board. I need to find a test track in the DFW area to run our cars. Our pack only sets up a portion of the track the night before so it is difficult to make modifications before race day. Any help or advice is much appreciated.

What type of wheel and axle prep are you doing? Are you polishing wheel bores? If you are using a good drill jig with good alignment you can probably move you com back. I'm def not a pro but I have at least been able to improve based on the info on this site.

 

[BradleyP50]

A quick upgrade would be to cover the bottom pockets with clear plastic tape. Can you run oil?

We can only use graphite. I’ll add tape to our next build.

 

[BradleyP50]

What type of wheel and axle prep are you doing? Are you polishing wheel bores? If you are using a good drill jig with good alignment you can probably move you com back. I'm def not a pro but I have at least been able to improve based on the info on this site.

We polished the axles to 2000 grit and buffed with a polishing compound, but didn’t spend too much time on the bores. We tuned the cars that we have built so far to 1” over 4’-0”. From what I have seen on this forum, it should be 4” to 5”.

I guess a concern I have on the center of mass would be the lack of a test track. What range do most stay in?

 

[SuperSlow]

Once your alignment is drilled correctly adding that steer will allow you to be more aggressive with your weight placement. Within reason

 

[Castoro Racing]

We polished the axles to 2000 grit and buffed with a polishing compound, but didn’t spend too much time on the bores. We tuned the cars that we have built so far to 1” over 4’-0”. From what I have seen on this forum, it should be 4” to 5”.

I guess a concern I have on the center of mass would be the lack of a test track. What range do most stay in?

Here are a few things from our prep that you may consider, there is alot more info available on this site so I would advise to read as much as possible on here.

-We can only run graphite and go to 3k grit on axles before final polish.
-There are certain axles treatments that may add benefit including pledge
-bore polishing makes a big differences, we use DD4H products and follow his video
-our COM tends to be 1/2 inch or less.

This site has been a huge resource for us in gaining speed, there is alot more available on here

 

[SuperSlow]

Wow 1/2 inch or less is pretty rebelious for a jumping off point

 

[Castoro Racing]

Wow 1/2 inch or less is pretty rebelious for a jumping off point

I'm just saying that's what we use, what works for others I am sure will differ.

 

[SuperSlow]

Absolutely, I fallowed in far more races than I won. For me there is only winning and learning