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-   -   my FC corner weight #'s (https://www.rx7club.com/suspension-wheels-tires-brakes-20/my-fc-corner-weight-s-86035/)

Scott 89t2 06-06-02 02:17 AM

my FC corner weight #'s
 
got my car corner weghted today. the first time I rolled it onto the scales without even touching anything it was almost pefect 25% weight on every corner!!! but then I had to get in and screw it up LOL :)

3/4 tank, everything in car, spare, jack ect. and 75lbs sub box in trunk... sway bars disconnected.

I ended up with this in the end. (lbs)

front

816 733
844 791 3184 total. 2997 without me :D

the guy was trying to match the left front/rear balence % with the right front/rear balence %.

so the 816 and 844 is a 49/51% front/rear. and the 733 and 791 is a 48/52% front/rear. that's pretty much as close as you'll get with adjusting right height. next step for perfect would be to move weight around inside the car.

the other way to corner weight is to match the diagnal weights. so the LF+RR = RF+LR. well mine is only off by 40lbs which is probably pretty good too :D

also ended up with a total 48.6/51.4 front to rear :D


now I just gota figure out how to fix the fact that my rear camber is 0.9 degress different left to right....


http://www.members.shaw.ca/smacken/cornerweight.jpg

RacerXtreme7 06-06-02 02:07 PM

Excellent posts!!! I am REALLY surprised as to how well the stock Fc is balanced :D .

ARD T2 06-06-02 07:40 PM

Not me. hehe. Can't wait to put my JIC in and get that sucker perfect.

rishie

Scott 89t2 06-06-02 08:30 PM

it's imposable by just adjusting height. you'd have to move weight around in the car to get better. move battery etc.

Cheers! 06-06-02 09:55 PM

Scott,

are you suppose to be in teh car or out of the car when you corner weigh the thing

Scott 89t2 06-06-02 11:22 PM

in, that's why the left side is heaver :D

SpeedRacer 06-07-02 09:29 AM


Originally posted by Cheers!
Scott,

are you suppose to be in teh car or out of the car when you corner weigh the thing

Yes, you are supposed to be in your car when it's corner weighted, as well as any other "dead weight" that would be in the car when you are driving/racing or whatever.

Scott89t2 - I realize your car is for street use, but in racing prepared cars obviously there isn't much weight that can be moved around to change corner weights, so pretty much the only way to adjust corner weights is adjust ride heights. Its considered a small compromise for the handling gains of a properly corner weighted car. We are talking adjusting ride heights in millimeters, nothing visually noticeable though. Also in race prepared cars corner weighting is usually done diagnally. I am currently working on F2000 cars so the rear engine obviously makes the car heavier in the rear than front. Its about a 40/60 ratio. So the diagnal corner weights just need to show that ratio on each diagnal.

Most people who get coilovers get them only to be able to lower their cars, what they don't realize is that 1/2 of the purpose of coilovers is so that you can corner weight your car(as well as being able to have adjustable ride heighth of course). Corner weighting is one of the most commonly overlooked part of suspension tuning, its good that you have it taken care of now.:D

If you would like help/advice on how to corner weight your car by adjusting ride height(VERY slightly, not visually noticeable)shoot me off a PM or something like that.:)

KevinK2 06-08-02 11:35 AM

scott,

guy did good job, decoupling bars 1st is important, and should be reconnected with u in car, adjusted to be preload free.

corner balancing, for a given weight distribution, is done by % or by diagonals, as u noted.

as is, diag diff=30
816 733 diff=83
844 791 diff=53

with % balance, diag diff=2
808 741 diff=67
852 783 diff=69

in this case, % method also got close to diag balance. Your setup is close, but this would slightly help keep left front from being overloaded on right handers. Diag balance method will keep the R-L diff's the same: LF-RF=LR-RR.

You can also tweak to get rear corners to the same force, for best drag strip performance.

Scott 89t2 06-08-02 12:16 PM


Originally posted by KevinK2
scott,

decoupling bars 1st is important, and should be reconnected with u in car, adjusted to be preload free.

ya the only problem is I don't have adjustable endlinks *yet*

sigh, the money spending never ends does it... ;)

what still amazes me the most is my first numbers. when I first rolled on to the scales with OUT me in it. car just at equal height from when I installed the coil overs

749 730
770 746

:crzyeye: dam 20lbs off PERFECT 25% at each!! (749-750).
gota mount my seat in the middle! :D

peejay 06-08-02 12:22 PM

Couldn't you just do the adjustments with the bars attached? That way you could be compensating for any irregularity, no?

BTW - It scares me when people talk about getting adjustable coilovers sothey can adjust their ride height for car shows or whatever. So easy to get the corner weights severly messed and make driving scary!

KevinK2 06-09-02 11:00 AM

don't need adj end links for bars .... just use shim(s) under pivot bush brackets. shims easily made from alum flashing, etc.

slvr7 06-20-02 03:37 PM

Hey Scott, were you in or out of the car when the L - R rear camber difference was measured??
Anyway, you're not the only one with this 'problem'.
I consistently measure about .75 degree difference between L - R, with the car 'unloaded'. The difference does not change with the setting, ie. L=1.5, R = .75; or L =2, R=1.25. I have the MazdaCompetition adjustable link.
Actually, I can't remember which side is more negative right now. Above numbers were just for illustration. But if you have any insights or solutions, let me know, and I'll do the same.

Curtis
'86 GXL autox'r


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