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Tech Inspection, Corner Balancing Seminar 2/7/09
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TOPIC: Tech Inspection, Corner Balancing Seminar 2/7/09

Re:Tech Inspection, Corner Balancing Seminar 2/7/09 15 years, 11 months ago #3191

  • Big Dog
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Ken, I think I have a write up on the steps to remove the trans and the clutch. If you want that, I will try to find it.

As for the corner balance, two of the "sometimes I forgot" items are;

1. Unhook the sway bars, front and back
2. Sit in the car with weights to add for your drivers gear. Mine weighs about 15 pounds so I hold a weight plate. I also make sure I have water in the cool shirt box and about 3 or 4 gal. of gas as that seems to be the midpoint of gas for our sprint races. The other approach, of course, is to simple hold your drivers gear while in the car.

Corner balancing seems like a chore the first few times but, like everything else, gets easier with practice.

Anyone that is going to corner balance should have their ride height pretty well set and a proper four wheel alignment done prior to the balance. You will want to have a set of tires that are as much as possible a typical race set, not new and not worn out. I also put my hot pressure setting in the tires so they are inflated as they would be on the track.

Some people bounce the car after making adjustments but the great Norm Hamden, who taught me everything I know about corner balancing, insists on driving the car for a short distance to really settle it in prior to weighing it again. It is more trouble to take it on and off the scales but, that's what Norm does and he does seem moderately fast.

Have fun and I wish I was there. I may try to make the Feb. race but don't expect me just yet.

Big Dog
Jim Foxx

Re:Tech Inspection, Corner Balancing Seminar 2/7/09 15 years, 11 months ago #3192

  • Big Dog
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Oh, yeah.

When you hook your sway bars back up, have someone else do it with you in the car. You want them to have NO preload so that means set them with everything as you have it for the corner balance.

Big Dog
Jim Foxx

Re:Tech Inspection, Corner Balancing Seminar 2/7/09 15 years, 11 months ago #3230

  • rlofgren
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Got it. I do disconnect the sway bar links before corner weighting. the problem is that cars with the m030 front bar don't disconnect quite so easily. Also no adjustable links to take out preload. when i had that sway bar on my car, i just set the front coilovers to the same height and did all weight adjustments using the rear ride height adjustment thingies. Usually just adjusting one corner is enough. We should definitely be able to do more than one car and i will bring my toe plates for alignment also.

here are the numbers from my last session:

LF 716 RF 668
LR 728 RR 668

my scales aren't terribly accurate, but they have worked for me.

p.s. i think there is a writeup on trans removal on www.clarks-garage.com/ garage shop manual. I just took one out of my parts car, everything was pretty straight forward except sliding the torque tube to transaxle coupler. that was a pain to slide.
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Last Edit: 15 years, 11 months ago by rlofgren.

Re:Tech Inspection, Corner Balancing Seminar 2/7/09 15 years, 11 months ago #3241

Woo Hoo. I have the Weltmeister 28mm front adjustable swaybar and the 22mm rear adjustables so that will make mine easier to work on. I guess I'd better bring some dirty clothes so I can get down and learn how to play with my cars suspension settings.
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Re:Tech Inspection, Corner Balancing Seminar 2/7/0 15 years, 11 months ago #3251

  • pixrken
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Hey Jim,

Thanks for all the helpful hints. It is very much appreciated.

SId,

Yes, bring some dirty clothes. The purpose of this seminar is for all us of to learn how to make the adjustments ourselves.


I been reading up on corner balancing and now understand the math behind it.
Using Sid's numbers:
LF: 763 RF: 591
LR: 629 RR: 702

From this we get:
Front weight: 1354
Rear weight: 1331
Left weight: 1392
Right weight: 1293
Total weight: 2685

The front/rear balance is approximately 50/50. front: 1354 / 2685 = .5043 or 50.43% rear: 1331 / 2685 = .4957 or 49.57%

The left/right balance is approximately 52/48. left: 1392 / 2685 = .5184 or 51.84% right: 1293 / 2685 = .4816 or 48.16%
The left is 101 lbs heavier than the right.
Asking Sid to go on a diet and lose 101 lbs would make him too weak to drive the car and putting in 101 lbs on the right is not practical since we don't want to add weight.
Since we're not able to change the weight on the front or left or right or rear we can try to change the distribution of weight.
If the front of the car weights 1354 lbs and the left side is 51.84% of the car's weight then the front left tires share of the car's weight should be 1354 * .5184 = 701.9136 lbs. The front right should be 1354 * .4816 = 652.0864.
The left rear is 1331 * .5184 = 689.9904
The right rear is 1331 * .4816 = 641.0096

So the optimum corner weights (rounded up/down) in this example are:
LF: 702 RF: 652
LR: 690 RR: 641

Notice this correctly solves the diagonal cross weights:
LF (702) + RR (641) = 1343
RF (652) + LR (690) = 1342

To save you guys from doing the math I just wrote a program for this http://944spec.org/cornerbalance. Just enter your four corner weights and it'll calculate the optimum corner weights.

Of course knowing the optimum target corner weights is only half the battle, I have no clue on how to actually do the adjustments. That's the purpose of this seminar to get hands on experience on making the adjustments.
--Ken
Last Edit: 15 years, 11 months ago by pixrken.

Re:Tech Inspection, Corner Balancing Seminar 2/7/0 15 years, 11 months ago #3272

So looking at my numbers, I think I will need to:

Raise my left front so it puts more weight on my right front.

Raise my right rear so it puts more weight on my left rear.

I guess you can also go the other way by lowering the right front and lowering the left rear too.
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