Corner balance height then = corner balance height now?

Noel · 12-15-2003, 01:35 PM

I'm in the process of installing new torsion bars/shocks/bushings and had a question about the need to get my car RE-cornerbalanced.

If I set my heights to the exact height (At each corner) my car was at after my first corner balance a couple years ago, will the car still be corner balanced? (This obviously assumes that I put in the same about of weight that represents me plus have a half full tank of gas as before.)

So I guess the real question is:

Do new after market torsion bars on a car with the exact same corner ride height effect the corner balance?

Noel

masraum · 12-15-2003, 01:42 PM

No, There are two things that will through you off here.

If you set the angle of the spring plates the same and then set the car down the new torsion bars (if they are larger than stock) will require new spring plate angles, otherwise the car will sit higher.

Even more importantly, if you spend lots of time making all four corners set exactly the same (per axle) you can have the weights very off. Kind of like if you take a 4 legged table and saw 1 inch off of two opposite corner legs. The table should balance and be level, but the two legs will be supporting all of the weight, the same principal will hold true for your car. Anytime you alter the spline settings of the torsion bars you potentially change the corner balance. There is a chance that you get things exactly right, but that chance is not very good.

echrisconnor · echrisconnor's Garage

Almost any ride height adjustments and/or suspension changes will throw off your corner balance. Make your changes, do your corner balance, get an alignment.

c

Noel · 12-15-2003, 02:40 PM

Thanks for the reply. I do plan to consult the "Firch" method for setting the initial spring plate angle to get it in the ball park. I am also upgrading to Sway-Away adjustable spring plates, so adjusting the final ride height will now be as easy as adjusting the front.

My goal was to adjust all four corners to the heights they were at just after my initial corner balance. The height of the left and right front and rear was definately not comparable at that time. I'll have to look, but I think I had a 1/4 to 1/2 inch difference between left front and right front for example.

If I did match each corners' height to the previous "Balanced" height, am I balanced. Or will the additional weight of the larger bars throw it off that much?

Noel

masraum · 12-15-2003, 02:57 PM

Quote:

If I did match each corners' height to the previous "Balanced" height, am I balanced.

No

It's not the weight of the bars that changes anything, it's the adjustment of the new bars, you can have the same exact car, adjust it so that all for corners are exactly the same, and have a perfect corner balance, you could then adjust the suspension such that all of the heights were exactly the same as they were when the car was balanced, but have each corner off by 200lbs.

The height really doesn't have anything to do with the balance. Obviously if you change one it can/will change the other, but overall they do not share a linear relationship.

echrisconnor · echrisconnor's Garage

Like the 4 legged table analogy above, you can be way jacked and still have a "level" car. Or think about how you can get on your hands and knees and keep your back level but have different weights between your left and right hands and knees. You've just changed your diagonal weights.

You can get in the ballpark by making sure that your spring plate angles are matched and that the front t bars are indexed the same and adjusted similarly, however, that won't mean that you have truly balanced the car. The corner balance will be thrown off by any minor changes. To get balanced you really need to get on the scales.

Many people elect not to corner balance -- which is fine. If you're close, you may never notice the difference. However, if you track, DE or even push the limits of your car, you'll be allot better off being balanced.

Noel · 12-15-2003, 04:30 PM

Thanks guys. I think I am with you now. I'll just aim to get it close and then take it in to get properly balanced. At least having the Sway-Away adjustable rear spring plates will save me some labor charges.

Noel

911pcars · 11:22 PM

Here's one way you can get close to your previous setting.

Correction: Here's one way you can check ride height without influence from other corners.

For example, let's measure the rear end height. Disconnect the rear sway bar drop link to disable any side-to-side influence. Jack up the front of the car and support it exactly in the middle of the suspension crossmember. If you can get to this point, you have now eliminated any influence the front corners have on the rear end corners. Instead of a 4-legged stool, you now have a 3-legged stool with each leg more independent from the others. If the RR and LR are uneven, it's because of their individual height settings and not because of any influence from the opposite front corners.

Ditto for the front.

I have a corner balance worksheet on my site if you're interested.

Sherwood
http://members.rennlist.org/911pcars

Jeff Alton · 12-15-2003, 11:14 PM

I set my heights to the exact same as they were before I changed the bars and had weight jacked across the car like you would not believe!!!

Jeff

lateapex911 · 12-15-2003, 11:17 PM

Remember, a sway bar is a spring. A tire is a spring. A bushing is a spring, although we would like it not to be. We need to allow for those influences, or eliminate them.

When you corner weight your car, you will almost always end up with a car that has asymetrical ride heights. If your sway bar links can not adjust for that, you will be 'un' corner weighting your car when you hook them back up. They need to have adjustable end links. They should slip on with no force to have as little affect on the corner weights as possible.

Make sure your tires are inflated to the correct pressure.

Finally roll the car back and forth and make sure the suspension has settled after any spring change.

A lot of guys will take two seperate readings per change to ensure consistancy.

Jeff Alton · 12-15-2003, 11:25 PM

Noel, see my thread about corner balance. I would put a link here but I do not know how! Just search under my name. Lots of good tips provided and you can see what happened to me!!

Jeff

Noel · 12-16-2003, 05:41 AM

Thanks again guys.

Sherwood, I like the "Three Legged Stool" idea. I'm assuming I would need to remove the front wheels and then lower the front with the jack to the approximate "Before" height and readjust if necessary. Thanks again for the corner balance sheet. I did grab a copy of it.

Jeff, your right, there was a lot of good info in those threads. Thanks.

Noel