I couldn't sleep last night (betcha didn't think thread could start like that ), and i started wondering:

If you reduce the weight of a car by removing something that's on the bottom of the car, something below the center of gravity, would you be improving or decreasing the handling ability?

Obviously, you're reducing weight, but you're making it more (even if it's just a little) top heavy, or unstable (raising the center of gravity). Discuss

 

good question, I have no idea but I would like to know as well. What do you plan on removing below your center of gravity though?

 

you will still be betteroff. the pros out weigh the cons here.

 

nothing actually, i was just thinking that almost anything you take out of a car is above the center of gravity, or at least partially (ie A/C stuff, cruise control, etc...).

I dont know if anyone ever saw the Victory by Design for Jaguar where at one point they used an SOHC V12 in one of their race cars instead of the better DOHC V12 because the drivers all felt the SOHC (less top heavy) engine actually made the car feel better...even though it wasn't as good an engine.

 

I believe it depends on how much the CG (center of gravity) is raised. If the CG raises a few inches, then the lighter car may stop better, but handle in turns worse and therefore there may be no benefit to the weight reduction.

 

Hard to say without knowing exact numbers. Generally speaking an ounce saved anywhere is good. It's rarely a good idea to ADD weight to a car to adjust the CG, unless you have to deal with minimum weight rules.

Most CG 'optimization' is done by moving the essentials of the car that are the largest concentrations of weight. The three biggest are the engine, transmission and driver.

 

yup, the CG height and weight amount each affect different aspects of the car...i think in almost all cases lighter would be better unless you can prove otherwise

 

if you're worried that much about it, remove the offending weight, then relocate the battery to behind your seat, which puts an extra 30ish lbs. at one of the lowest points of the car...

 

well this was a hypothetical question

there isn't really anything i can think of in your average car that could possibly be removed and significantly affect the CG (no one would be stupid enough to take out subframes or crossmembers...).

thinking of F1 cars however, they have the regulated skidplates or whatever it is beneath the cars... that's what got me thinking... either way i'm sure that physics can provide an answer given precise values...

 

F1 cars are built to a minimum weight. I believe that as of 2000 Ferrari built their cars about 200 lbs underweight and adds tungsten (I think...) ballast in the floorpan to lower the CG. Not positive about the numbers, though.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kablamo &raquo;</TD></TR><TR><TD CLASS="quote">well this was a hypothetical question

there isn't really anything i can think of in your average car that could possibly be removed and significantly affect the CG (no one would be stupid enough to take out subframes or crossmembers...).

thinking of F1 cars however, they have the regulated skidplates or whatever it is beneath the cars... that's what got me thinking... either way i'm sure that physics can provide an answer given precise values... </TD></TR></TABLE>

the skidplates are not part of the weight balance though, they're made from light weight material.

alot of race cars are built below minimum weight, so then you can strategically place the weight you need to get to the minimum weight

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Angry Joe &raquo;</TD></TR><TR><TD CLASS="quote">F1 cars are built to a minimum weight. I believe that as of 2000 Ferrari built their cars about 200 lbs underweight and adds tungsten (I think...) ballast in the floorpan to lower the CG. Not positive about the numbers, though.</TD></TR></TABLE>

This is a fairly common technique (from what I've seen). If you reach minimum weight with rules to spare you have the excellent opportunity to relocate to positively change the CG (and balance).

Example :

1. Your car is at min weight.
2. You still have glass windows but you can run lexan legally.
3. Replace the windows and add ballast weight strategicly to balance the car and lower the CG.

 

yes, but if you let them take that weight back out they would in a heart beat. less weight is allways a good thing.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 577HondaPrelude &raquo;</TD></TR><TR><TD CLASS="quote">yes, but if you let them take that weight back out they would in a heart beat. less weight is allways a good thing.</TD></TR></TABLE>

All things being equal? yes... I would agree. There are always some exceptions as well. My example refers to a car that I see every now and again and local/national autox events. I left out that he was having a SEVERE problem with inside wheel lift on right turns... BOTH INSIDE WHEELS. The car is much better behaved now... I don't know if just the lexan change would have been enough, but he was already at min weight already so that wasn't an option.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Watkinsm3 &raquo;</TD></TR><TR><TD CLASS="quote">

All things being equal? yes... I would agree. There are always some exceptions as well. My example refers to a car that I see every now and again and local/national autox events. I left out that he was having a SEVERE problem with inside wheel lift on right turns... BOTH INSIDE WHEELS. The car is much better behaved now... I don't know if just the lexan change would have been enough, but he was already at min weight already so that wasn't an option.
</TD></TR></TABLE>

Sounds like more of a chassis/suspension issue rather than a weight issue. The weight cured the problem, but it wasn't the cause.