Weight Placement

B_Regal Racing

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Pro Racer
Apr 1, 2014
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...can make as much of a difference in speed as steer.
idea


That is all.
 
Aww c'mon BRR

You have more to say on the topic.

Just let it out. You will feel better afterwards.

No doubt JBD will be cool with it.

Now, do tell.

What were the findings?

Thanks,
 
I have always heard that weight placement makes a difference in speed and I actually have a demonstration car I used to show Scouts the effect weight has; however, the demonstration car is not tuned. What I did was to intentionally build cars with more precise weighting, tune them (e.g. adjust steer), and look for a pattern in weight placement. What I found only supports what was already written - I could not find a standard weighting that is optimal for every car. Each car was different and needed very different weighting to be at their fastest. What I did notice is a significant drop off in speed with a car not weighted properly. I could not correlate bad weighting to speed (e.g. the worse the weight, the larger the drop off), but what I can say is that you will absolutely know when you find the sweet spot where everything works. I look at the times the top racers are running. While prep makes a difference, it does not account for 3 to 5 100ths of a second. I believe weighting plays a significant part in this. Remember though, most are faster than me, so this may already be known to most. Hopefully, some of this pays off in my BASX car, Taxi; or maybe I'll be a laughing stock. Either would be acceptable.
 
It would be interesting to see a bell curve on each major contributor (showing the importance of each) , Weight, steer, wax, wheel weight, oil, cant (and a few others) and see which ones have the biggest difference. I've always thought Wheel weight would be one of the bigger ones.
 
B_Regal Racing said:
I have always heard that weight placement makes a difference in speed and I actually have a demonstration car I used to show Scouts the effect weight has; however, the demonstration car is not tuned. What I did was to intentionally build cars with more precise weighting, tune them (e.g. adjust steer), and look for a pattern in weight placement. What I found only supports what was already written - I could not find a standard weighting that is optimal for every car. Each car was different and needed very different weighting to be at their fastest. What I did notice is a significant drop off in speed with a car not weighted properly. I could not correlate bad weighting to speed (e.g. the worse the weight, the larger the drop off), but what I can say is that you will absolutely know when you find the sweet spot where everything works. I look at the times the top racers are running. While prep makes a difference, it does not account for 3 to 5 100ths of a second. I believe weighting plays a significant part in this. Remember though, most are faster than me, so this may already be known to most. Hopefully, some of this pays off in my BASX car, Taxi; or maybe I'll be a laughing stock. Either would be acceptable.

Good stuff BRR!

Ok. Now spill it.

How biased was the weight?
Thanks,
 
I have read the same thing about weight placement. The last two races my cars where ok, I have played with steer but did not see any real improvement, so I decided to play with the weight placement for M.O.M. I don't have a track, so I'll have to see how they run on Saturday.
Craig
 
I noticed pretty quick just adding a ball of putty to get up to 5 oz can change the steer on my tuning board. The first time I tuned before and after it changed 2 inches if I remember right.

Can you say what kind of different weight placements you tried? So far without a track I have just been biasing any extra weight after the 2 rows of 6 cubes packed front of the axles in the corner on the DFW side. I think my next round I may go less aggressive with my COM. I think it is at .5"
 
Two of the cars I sent in had two rows of six cubes in front of the axles with a little putty in front of the two rows on the DFW side I took two cubes out of the front row and moved them next to the putty. I'll learn something Saturday.
 
I don't have 1 car that the cubes are placed the same ... Far as steer and weight placement it does play a role. COM. Also effect the amount of steer you can run... But all cars are different . I have some cars that have 2 inches & some that have 7 inches... A car will tell you what it's wants if you watch it and listen!! /images/boards/smilies/smile.gif/images/boards/smilies/smile.gif/images/boards/smilies/smile.gif
 
laserman said:
Good stuff BRR! Ok. Now spill it. How biased was the weight? Thanks,

I just randomly installed weight slightly heavier in the DFW side. No specific formula, but to echo what JBD said, the car told me. Literally. I just kept re-weighting until the car suddenly came alive. I know I might sound evasive, but when I discovered how this car wanted to be weighted ("Taxi" in the BASX class), it was became easy to set the steer and run straight. I could literally see it.

I can not say I could hear it, but that is an interesting statement.

I will say that I went back and started to tinker with some of my other cars and broke my best car (Ghost) ripping the weight out of it. Why I glued it in, I have no idea. But, I cracked the frame, used some bondo to strengthen it in a place where you would not ordinarily add weight, and subsequently lost a 100th or more. This car, which finished 3rd on the 63' track, I can no longer find that sweet spot. It told me it was a crippled old man (but I sent it in anyway).

I can say this - JBD is absolutely correct (at least what I'm finding), there is no set weighting thats going to work on every car, or even most cars. I now am convinced of this. I'll know for sure when I see Taxi run...a butt ugly yellow and orange car.
 
~JBD RACING~ said:
I don't have 1 car that the cubes are placed the same ... Far as steer and weight placement it does play a role. COM. Also effect the amount of steer you can run... But all cars are different . I have some cars that have 2 inches & some that have 7 inches... A car will tell you what it's wants if you watch it and listen!! /images/boards/smilies/smile.gif/images/boards/smilies/smile.gif/images/boards/smilies/smile.gif
Hi JBD,
To be honest I have played with my cars steer in the 2" to 4" in 4' on my fancy MDF tuning board. /images/boards/smilies/smile.gif When you talk about 2" and some at 7 " are you using a 6' tuning table?
Thanks Craig
 
Well, that makes me feel better. I have a car I've had at 3-1/2" with bad wiggle, 4" with bad wiggle, now trying 4-1/2" this weekend.

hmmm...I may have to go all the way to 7", didn't think a car could be fast with that much steer. This is the car that "drove" me to purchase a track! ha!
 
~JBD RACING~ said:
44 inch Tuning board ..
Thanks JBD,
I would have never tried 7" on my short board. You have definitely taught me that I have to think outside my box. LOL My test track is on race day so I'll see what happens on Saturday.
Thanks again Craig
 
Bullet said:
Well, that makes me feel better. I have a car I've had at 3-1/2" with bad wiggle, 4" with bad wiggle, now trying 4-1/2" this weekend.

hmmm...I may have to go all the way to 7", didn't think a car could be fast with that much steer. This is the car that "drove" me to purchase a track! ha!

Maybe put more weight towards the DFW and/or check rear wheel gaps. Just a thought.