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Corner weighting

Old 08-05-03, 09:53 PM
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Question Corner weighting

Hi all,
I just had my car corner weighed. Car is a 1985 GSL-SE w/ opt. p/s. Car is complete. Installed are: GC coil overs and camber plate w/ 2nd Gen MR2 Illumina rear shox up front. Illuminas and ISC racing adj. height spring perches in the rear.

Results:
Total weight w/ driver =( 2727 lbs
w/o driver 2527 lbs
Left side wt. w/ driver= 1445 lbs
Right side wt. w/ driver = 1282 lbs

Lft ft: 789 lbs Rt ft: 662 lbs
Ride ht: 13 9/16 in Ride ht: 13 9/16 in

Lft rr: 656 lbs Rt rr: 620 lbs
Ride ht: 13 3/4 in Ride ht: 14 in

These are the 1st measurements. Anything I can do to bring these to more optimum balance? The car is used for club cruises w/ autox and some road courses thrown in for fun!
I have access to the scales whenever I want so I can play w/ it all day if I need.

TIA!

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Old 08-06-03, 01:02 AM
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So, LF/RR = 1409
RF/LR = 1318

So about 51.6% vs 48.4. That's a big difference, and will have an impact on how the car handles turning left vs right.

That can definitely be improved if you have coilovers all around. First of all, is your surface absolutely level? These measurements are moot if not, even a small angle will affect the amount of weight on one tire. I use floor tile samples under the scale, a straight edge and a level to determine if my scales are level.

Put the driver in the car, and fill the tank to where you expect to be racing at (we filled ours to 3/4, you may only want 1/4 or 1/2).

Measure one more time to make sure your numbers jive.

Then if it were me, I'd start by raising the Left Rear a 1/8". that will raise the weight on the LR and RF wheels, and decrease the weight on the LF and RR.

Aside from removing/adding/moving things, the only thing you can modify is the cross weight percentage. Your L/R and F/R weight distribution is static, the only way to modify this is to physically remove/add things in the car or shift them around. Your class rules may allow you to do this, I'm not sure what class you run.

Search this forum, I posted my numbers about 6 months ago on my car.

PaulC
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Old 08-06-03, 08:17 AM
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Don't forget to set the tire pressures and disconnect the sway bars, as both of these will screw up the numbers. Write the weights down after each adjustment and note what you did to get there. That way when you screw it all up (trust me you will) you'll have a guide to get you back.
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Old 08-06-03, 11:27 AM
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Reloacte the battery if allowed.
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Old 08-06-03, 12:57 PM
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PaulC,
The scales were leveled using a laser level set in the "middle" of the scales.
Racer John,
The tire psi is set at 30 ft and 28 rr. No rear bar but the front was in. I see your point about the bars making a weight diff. But dont you want it in when doing this? If you put it back on it'll change again. No?
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Old 08-06-03, 06:43 PM
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Just remove one end link and let it hang, that'll negate any tension on the suspension.
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Old 08-07-03, 09:59 AM
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Yea, you dont want preload. Also bounce the car up and down a bit on front and back before your readings to settle the suspension. And after each change do it again so its settled.
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Old 08-07-03, 10:38 PM
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Thanks all for the suggestions! I'm still up in the air about the sway bar. Unless, hmmmm. The bar is installed w/ the car on a flat surface. The bar ends are setup parallel to the LCA's right? Basically no pre-load. If that's the case, then why disconnect the bar?
HMMM?
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Old 08-08-03, 02:50 AM
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Jeez Gary, it's one bolt, are you THAT lazy?

Do it, don't do it, up to you. We don't get paid any extra.

PaulC
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Old 08-09-03, 12:30 AM
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I am that lazy. LOL.
I'll unbolt it and do the balancing act. I'll let you know what happens when its put back on.
My last reply was asking what the correct way to installl a swaybar was.
Thanks!
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Old 08-09-03, 03:39 PM
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Unbolting the sway bar is important if you can/will adjust it to zero preload once cornerweighted. In other words, don't bother disconnecting it if you are not gonna zero it's preload (via adj length end links perhaps) after cw'g the car.
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Old 08-11-03, 10:38 AM
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Unbolting the sway bar is important if you can/will adjust it to zero preload once cornerweighted. In other words, don't bother disconnecting it if you are not gonna zero it's preload (via adj length end links perhaps) after cw'g the car.
Yeah what he said... This is the part I forgot to mention Also about the tire pressures set them to what you want them to be when you come off the track hot. So if your goal psi. is 40 set them to 40.
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Old 08-13-03, 11:16 AM
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Thanks, I be getting on the scales on thursday. I'll try things out.
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