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Old 07-11-2007, 02:58 PM   #1
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Default Lap times vs. weight of car

Has anyone experimented with lap times vs. reducing the weight of your car?
I know reducing rotational weight is more critical than reducing static weight.
For example, if you reduced the weight of the drive train by 10g, 20g, ect, how much (if any) did your lap times change?
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Old 07-14-2007, 05:28 AM   #2
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Old 07-14-2007, 05:41 AM   #3
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Lighter is always gonna be faster and more nimble. How much I don't know, but I'm sure it's a decent percentage.
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Old 07-15-2007, 11:52 PM   #4
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that why they have a min weight rule at most clubs.

I do have different veiw on this subject. if the track is very flowing. what is in motion stay in motion. so if you and can flow around the track with very little breaking( what i have breaks). a slightly heavier car might be faster as it doesn't have to accellerate has much. As it stay in motion easier. but if the track if full 180 and you have to break tons. a lighter car would be more benificail( Man I can spell today. but you get the jist of it)

I know when I finally got my car up to proper weight requirements I was doing fast lap times. Heck maybe I finally learned how to drive. I also found out I was over weight too. by 25gm.
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Old 07-16-2007, 03:10 PM   #5
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I know most clubs have a weight limit, but is isn't always enforced. I guess no one did any testing to find out this information.
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Old 07-16-2007, 05:13 PM   #6
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Quote:
Originally Posted by magerp View Post
Has anyone experimented with lap times vs. reducing the weight of your car?
I know reducing rotational weight is more critical than reducing static weight.
For example, if you reduced the weight of the drive train by 10g, 20g, ect, how much (if any) did your lap times change?
Generally what I try to do is set my car to the ROAR specs when it comes to weight. I use the same weight at club races so that way when I add wieght at a big race to comply, it doesn't mess up my setup.
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Old 07-16-2007, 05:51 PM   #7
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Last year at the KO Propo race, the minimum weight was 1525 grams. This year at the Reedy Race the minimum for 6 cell was 1525 grams, and 1450 for 5 cell. I try to keep my car at 1525 minimun and work with that. Reedy race cars with 5 cell didn't seem to have the same zip as 6 cell cars but were putting in the same lap times. I would guess having less weight to carry makes the car take turns easier.
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Old 07-16-2007, 09:08 PM   #8
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Thanks for the info. I don't race any large events so I don't worry about what roar says. I don't feel like racing every 6 hrs.
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Old 07-16-2007, 10:15 PM   #9
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Quote:
Originally Posted by cyrrus View Post
that why they have a min weight rule at most clubs.

I do have different veiw on this subject. if the track is very flowing. what is in motion stay in motion. so if you and can flow around the track with very little breaking( what i have breaks). a slightly heavier car might be faster as it doesn't have to accellerate has much. As it stay in motion easier. but if the track if full 180 and you have to break tons. a lighter car would be more benificail( Man I can spell today. but you get the jist of it)

I know when I finally got my car up to proper weight requirements I was doing fast lap times. Heck maybe I finally learned how to drive. I also found out I was over weight too. by 25gm.
"An object at rest will stay at rest, and an object in motion will stay in motion at constant velocity, unless acted upon by an unbalanced force."

Well the unbalanced force here is gravity, and a heavier car will be more affected by gravity. I'm no scientist but it seems like a lighter car would be better.
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Old 07-16-2007, 11:15 PM   #10
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I think that's generally going to be true, but when you make a car lighter than the intended/designed weight, lots of other things need to be adjusted to compensate. Spring and damper rates, inserts, tires...lots of stuff.

It would definitely be faster, "apples to apples" no way around that...but it may take some work to get there, setup-wise.
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Old 07-16-2007, 11:25 PM   #11
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Quote:
Originally Posted by cyrrus View Post
that why they have a min weight rule at most clubs.

I do have different veiw on this subject. if the track is very flowing. what is in motion stay in motion. so if you and can flow around the track with very little breaking( what i have breaks). a slightly heavier car might be faster as it doesn't have to accellerate has much. As it stay in motion easier. but if the track if full 180 and you have to break tons. a lighter car would be more benificail( Man I can spell today. but you get the jist of it)

I know when I finally got my car up to proper weight requirements I was doing fast lap times. Heck maybe I finally learned how to drive. I also found out I was over weight too. by 25gm.
Theoretically the less inertia the better. A lighter car will brake quicker and accelerate faster. Now if you tend to brake too soon, maybe a heavier car will help.
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Old 07-17-2007, 08:22 PM   #12
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The less inertia the better. Inertia stores energy when accelerating, that will go into heat when braking.
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Old 07-17-2007, 08:37 PM   #13
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Quote:
Originally Posted by magerp View Post
Has anyone experimented with lap times vs. reducing the weight of your car?
I know reducing rotational weight is more critical than reducing static weight.
For example, if you reduced the weight of the drive train by 10g, 20g, ect, how much (if any) did your lap times change?
It's all rotational weight when your going around a corner
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Old 07-17-2007, 08:46 PM   #14
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This depends on the track and race conditions. In the oval racing that I do, the minimum weight is 42oz. At the short tracks I try to be as close to that as possible. On the velodrome tracks I give up some weight to add aerodynamics, high-speed caps, and durability. Last time I think the car weighed in close to 47oz. The cars with the smooth chassis that seals with the body are quicker through the air. This is an extreme example ... corner speed is almost the same at straightaway speed so the rotational weight and the static weight aren't a concern as much as aerodynamic drag. We also run large front bumpers - it is better to survive a wreck and keep racing than to gain .05 seconds per lap and not finish a race.
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Old 07-17-2007, 10:02 PM   #15
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Thanks for all the info. If I want to take .1 sec of my lap time; and the only thing I change is the weight of the car, I should remove _____ grams from the car. If no one has any hard data, educated guesses would be welcome.
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