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can a 20b equipped 3rd gen retain the 50:50 weight distribution?

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Old Nov 17, 2004 | 12:51 AM
  #26  
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You can't make a 40/60 car 50/50 with corner balancing (nor would you want to), but you can make small adjustments in ride height to ensure that the balance from corner to corner diagonally (right front to left rear, left front to right rear) is equal so that the car will corner the same turning left as it does turning right.

If you raise ride height at one corner, it puts more pressure on the tire at the opposite corner. If you lower ride height at one corner, it reduces pressure on the tire at the opposite corner. Pretty simple.

Originally Posted by kento
Gravity doesn't change with height.
No, but pressure changes with leverage...

Originally Posted by Steve Cirian
http://www.scuderiaciriani.com/rx7/c...balancing.html

My car was done w/ a quarter tank of gas and 220 lbs in the driver's seat. Penske coil-overs w/ Eibach springs. For more details, go to Scuderia Ciriani --> The Car.

I did not get the corner weights in pounds from the shop that did mine. He gave me the percentages. It has quite a bit off from what I expected - something like:

LF: 29% RF: 28%

LR: 22% RR: 21%

I forgot to check the sheet I got from the shop when I was home this weekend, but these should be pretty close. Traveling all the time for business sucks.

If we assume that my car weighs 2600 lbs, plus 220 for me, I get:

LF: 818 RF: 790

LR: 620 RR: 592

This isn't as balanced as I expected, but the shop that did it said it was the most balanced street car (i.e.- not open wheel race car) they had ever seen. Maybe I need to go on a diet - that would drop the weight in the driver's seat and even things out.

I think this is not accurate - maybe the shop that did it (Havoc Motorsport in Chicago) forgot to write down what the weights were, and guessed at it after the fact.
Steve was puzzled by the results of his corner balancing, but if you add up the weights (or percentages) of the opposite corners...

RF: 28% + LR: 22% = 50%
LF: 29% + RR: 21% = 50%

RF: 790 + LR: 620 = 1,410 lbs.
LF: 818 + RR: 592 = 1,410 lbs.

Right on the ******* money. That's what corner balancing is all about. Not having equal weight at each corner.
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Old Nov 17, 2004 | 01:07 AM
  #27  
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interesting
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Old Nov 17, 2004 | 01:14 AM
  #28  
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Is it best to, when tuning the suspension by corner weighting a car, to be in it while its being done, to take into account the added weight of a driver?
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Old Nov 17, 2004 | 01:19 AM
  #29  
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Originally Posted by F0RSAKEN
Is it best to, when tuning the suspension by corner weighting a car, to be in it while its being done, to take into account the added weight of a driver?
Any shop worth its weight will put ballast in the driver's seat to simulate having the driver in the car. Steve's car had 220 lbs. in the driver's seat, as mentioned above.
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Old Nov 17, 2004 | 02:19 AM
  #30  
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I see, thanks a lot guys.

So following what jimlab said, the scales are displaying weight (lbs), but in actuality it would seem that they are measuring the pressure being exerted on them, and then converting it back to weight?

-s-
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Old Nov 17, 2004 | 03:27 AM
  #31  
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nice explanation jimlab.
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Old Nov 17, 2004 | 07:04 AM
  #32  
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Originally Posted by scotty305
I see, thanks a lot guys.

So following what jimlab said, the scales are displaying weight (lbs), but in actuality it would seem that they are measuring the pressure being exerted on them, and then converting it back to weight?

-s-
Pressure on the scales is weight. They aren't converting anything. A set of corner weight scales includes 4 individual scales; one under each tire. Each scale displays the individual weight at that corner. Add the 4 corners and that's the total weight of the car. Monkey with the perch settings and watch the weights change.

The scales are showing how hard each corner of the car is pushing against the ground. Corner weights are just that: corner weights. You can move weight around opposite and adjacent corners but you CANNOT move it around front and rear axles (except in very small amounts by changing rake). Corner weighting is about corners; not front ends, rear ends or sides.

Everybody has latched onto adjustable perches on coilovers and know just enough to be dangerous.

Last edited by DamonB; Nov 17, 2004 at 07:18 AM.
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Old Nov 17, 2004 | 07:09 AM
  #33  
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Originally Posted by jimlab
If you raise ride height at one corner, it puts more pressure on the tire at the opposite corner. If you lower ride height at one corner, it reduces pressure on the tire at the opposite corner.
If you raise a spring on a corner you are actually adding weight to that same corner (since now the spring is compressed more and therefore takes on more load) as well as the opposite corner. Raising the left front would add more weight to both the left front and the right rear while subtracting weight from the right front and left rear.
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Old Nov 17, 2004 | 07:10 AM
  #34  
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How to corner weight by Grassroots Motorsports

Last edited by DamonB; Nov 17, 2004 at 07:18 AM.
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Old Nov 17, 2004 | 11:50 AM
  #35  
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Great link, thanks DamonB. Looks like I had it backwards about the effects of raising/lowering ride height. According to GRM, raising a corner will increase the weight at that corner. I should renew my subscription to GRM, I miss that magazine.

-s-
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Old Nov 17, 2004 | 12:24 PM
  #36  
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Originally Posted by scotty305
I see, thanks a lot guys.

So following what jimlab said, the scales are displaying weight (lbs), but in actuality it would seem that they are measuring the pressure being exerted on them, and then converting it back to weight?

-s-
f=ma
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Old Nov 17, 2004 | 12:31 PM
  #37  
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Originally Posted by DamonB
If you raise a spring on a corner you are actually adding weight to that same corner (since now the spring is compressed more and therefore takes on more load) as well as the opposite corner. Raising the left front would add more weight to both the left front and the right rear while subtracting weight from the right front and left rear.
Yep. I simplified my explanation too much.
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