ok, i have been reading a lot about suspension tuning over the past year or so and one question has yet to have been answered by the books i have read.

if you have a car that is for racing only and for conversation sake lets say that there are no rules as far as chassis and suspension mods go, do you account for drivers weight with equal ballast on the passengers side, or do you use a different suspension setup for each side?

all of the books i read make it clear where you want the weight to be and how to adjust hieght and whatnot to account for the weight, but would it be worth it to add ballast so that the car is virtually equal in all aspects?

what do you guys do?

 

I've never heard of adding ballast to the car specifically for weight balancing purposes, but lots of people have to carry balast to make minimum weight and it can help the balance when placed correctly. To balance the car, most people will corner weigh the car and adjust the ride height on each corner such that the sum of the diagonal weights (RR+LF vs LR+RF) are as close as possible to each other.

 

w00t? Put the driver in the middle! Hell, put everything you only have one of in the middle if you don't have packaging constraints to deal with.

Taking an object from the left side of the car and putting it on the right side will shift cg farther than simply adding ballast of the same weight. If you're making the car heavier, you'd better be doing it with something functional.

 

well, i know adding weight isnt a usually good idea, but lets say you have a normal car such as a miata and you get a good front to back weight distribution, but the presence of the driver makes one side of your 2400lb car consideranly heavier than the other. i have read all about how you can balance it out and everything. but if you add ballast and therefore you end up with equal weight distribution, wouldnt that mean that you can run similar spring rates and damping on both driver and passenger side.

i am not saying this stuff as if i know, i am only offering what seems to make sense, so please feel free to correct me if i am wrong.

but the way i see it if the driver only weighs 150 lbs you could balance him out with another 150 on the passenger side and then the car will behave the same no matter which way you are turning versus having an unbalanced car and having to adjust the suspension to counteract the imbalance.

help me out here

 

You're overcomplicating the wrong part of the equation. Static weight distribution only applies when the car is parked. You want to use as much freedom of design as possible to get things where they need to be, then cornerweight with the driver in the car to get things as balanced as possible. After that, you worry more about what happens when you're moving.

 

You seem to assume that without the driver the car is balanced. There are a lot of things on the car that are not symetrical. Exhaust, driver controls, battery, etc... not to mention things you have removed to from the car depending on what you're doing with it.

Taking your assumption into account, why not remove 150lbs from the driver side. Or move 75lbs of critical componenets to off set the driver.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by chjkingme &raquo;</TD></TR><TR><TD CLASS="quote">as balanced as possible. </TD></TR></TABLE>

wouldnt it be better to balance it as best as possible before you go to corner wiegh it? so if you allready have ideal weight distrinution and the you can fine tune it on the croner scales but you are having to compensate to a lesser extent

 

tire grip does not increase linearly with normal force. lighter is always better, even at the expense of a slightly poorer left side percentage. of course, driven to extremes this doesn't hold true, but 5% differences in left/right weight is nothing to worry about if your only solution is to make the car heavier.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by solo-x &raquo;</TD></TR><TR><TD CLASS="quote">tire grip does not increase linearly with normal force. lighter is always better, even at the expense of a slightly poorer left side percentage. of course, driven to extremes this doesn't hold true, but 5% differences in left/right weight is nothing to worry about if your only solution is to make the car heavier.</TD></TR></TABLE>

ok. i get ya