Slantnose!

Hello.
Just did an alignment yesterday and then threw on the scales:
LF 1023; RF 831
LR 738: RR 1011
Car is level, but I know I really need to get this much closer.
How close should these weights be and is there a way better than another to do it?
Thanks.

mark kibort

correction: Raise your right front and left rear by a couple of turns of the ride hight adjusters or lower the Left Front and Right Rear a couple of turns. that will get you right where you need to be. on a street car, the corner balancing is not really nessesary or effective. Do you ever brake and turn? that weight transfer has to be considered and is dependant on many other factors. (bump, rebound, springs, swaybars, tires, driver input and style, etc etc) however, your cross weights are a little off, so to tighten them up, just a couple of turns on the adjusters as i mention should put you right in line.

mk

Jim bailey - 928 International

You have what is like a wobbly table LF RR carrying more weight and match books under the other two legs to keep it level. The rear is off by nearly 300 lbs that is significant about 40 % .

mark kibort

now picture two olymipic weight lifters lifting the right front and the left rear. all they need to do is lift the car up 100lbs and the corners go up 100lbs while the other opposing corners go down by 100lbs. suddenly, you are balanced based on what i have done, a couple of turns on the shock ride hight adjusters will do the trick. worst case, it will be much better. best case it could be near perfect.

dr bob

We did a litttle evening special-stages run a couple years ago. One of the participants had recently replaced springs-n-shocks, but the corner balancing issue became apparent when the car shifted weight side to side whenever the car shifted weight front to back, and vice-versa. It was enough of a problem that it did a little off-road excursion when other cars in the group were just breezing the corners.

Mark's method of moving a little weight with the diagonal shock adjusters is right on. Plan on verifying the corner weight again after you've driven the car a bit. Moving the adjusters is a start but the suspension needs to be moved around some by driving before an accurate corner-weight can be verified on the scales.

Also-- you now know what your car weighs!

Donald

Mark:
perhaps this is semantics, but maybe it is my understanding- this sounds counterintuiituve to me. Wouldn't you want to lower (increase the length of the suspension) RF and LR to increase the weight on those two (& decrease weight on LF and RR)?

GUMBALL

I think that you both are saying the same thing - turn the adjustors up to lengthen the loaded length of the RF and LR.
I think Mark is pretty close - if the height is correct, I would go up 2 turns on RF/LR, and down 2 turns on LF/RR.

And I beg to differ regarding corner weights on a street car - when mine was done, it made a noticeable difference in the way the car handled bumps, undulations, and uneven pavement.

IcemanG17

I need to get mine aligned and balanced once I get some new shocks....

Bill Ball

Just checked mine last night. 1/2 tank of gas. I can't remember the exact numbers. I think it was 52+% rear, 48-% front. Fronts almost equal side to side, as well as rear. I think they were within 10 lbs side to side. Note that I had adjusted the spring lengths the same side to side (using the exposed adjuster thread as a gauge). This made the ride heights somewhat unequal, but the comment I have seen that balance is good when the springs are the same length seems to be true for my car.

Charley B

When they don't match up, is it better to adjust for corner weight or ride height?

GregBBRD

Your car is severely "corner jacked". It is possible to make a car perfectly level and carry the main weight of the car on two of the corners. This looks like the case with your car. Here's how to figure this out correctly:

1. Sway bars need to be disconnected to eliminate any preload on bushings. This is particularly important with rubber sway bar bushings.
2. Tires need to be inflated correctly. Make sure tires are the correct sizes and are both the same in the front and both the same in the rear.
3. Weights should be taken with the driver in the car and the tank 1/2 full.
4. The area where the car is weighed must be perfectly level.

I'm going to assume this is true for your car and actually calculate the results and the desired weights.

We corner balance until the cross weights are off by less than 25 lbs. and the actual calculated corner weights are with-in 5 lbs. This is for a track car. Street car can be tough to get this close. 50lbs. and 10 lbs, respectively, should be easy to do.

Here's how to do the calculations:

Add all four corners to get total weight: Your's is 3603

Add LF to RR: Your's is 2034

Add RF to LR: Your's is 1569

Subtract these two numbers to get the difference in cross weights: Your's if off 465 lbs. This is pretty much as bad as it can get! The record for a race car in our shop is 525 lbs! It didn't work too well!

Add the LF to the RF: Your's is 1854.
Add the LR to the RR: Your's is 1749.

Divide the first result by the total weight (1854/3603). This is the percentage of front axle weight. Yours is 51.5%

Divide the second result by the total weight (1749/3603). This is the percentage of rear axle weight.
Yours is 48.5%. If these two numbers don't add up to 100%, redo your math.

Add the LF to the LR. Your's is 1761.
Add the RF to the RR. Your's is 1842.

These are the side to side weights. These allow you to find the correct corner weights.

Multipy the left total by the front percentage (1761 x .515). Yours is 907. This is your "target weight" for the LF. Subtract this from the actual measured weight and your LF corner weight is off 116 lbs. This sucks.

Multiply the right total by the front percentage (1842 x .515) Your's is 949. This is your "target weight" for the RF. Subtract this from the actual measured weight and your RF corner weight is off -118 lbs.

Multiply the left total by the rear percentage (1761 x .485). Your's is 854. This is your "target weight" for the LR. Subtract this from the actual measured weight and your LR corner weight is off -116lbs.

Multiply the right total by the rear percentage (1842 x .485). Your's is 893. This is your "target weight" for the RR. Subtract this from the actual measured weight and your RR corner weight is off 118 lbs.

Again, this car is off a ton. It is severly "corner jacked". Now you need to find out what corner you need to start adjusting on.

Raise the back of the car in the exact middle of the rear cross piece for the suspension until the rear tires are off the ground. Measure the distance from the front suspension to the ground on both sides. Adjust the front springs until these heights are the same. You can either raise the low side or lower the high side. You need to choose. You will need to make a change, go drive the car and recheck the heights, as the lower front A-arm bushings bind severely.

Once the front is level, reweigh the car and recalculate the results. The rest of the changes to get the proper weight is done in the rear of the car.

Once this is all done, the car will need to be aligned, since ride height effects camber.

Have fun.

gb

mark kibort

The concept is as Bob and greg are saying, you could have no weight on the light corners and the car would be teatering on the heavy corners. picture a table with two corner legs longer than the others. all the weight could actually be on just two corners.

so, to change that, you start to raise the light corners. like i said, quite simply, you can raise those corners by 2 or 3 turns and you will be very close. take it from me. I have one of the best handing 928s around, and im still in the 100lb cross weight range.

as far as street cars go, i have an easy time noticing when my sway bar breaks, but on the street, it would be almost imposible to notice cross weight issues based on street performance. maybe on a 911, but on a 928, the car is so well balanced, that it masks many of the handling issues that other cars would have if many of the main components are out of adjustment.

just turn up the light corners and like i said, you will probably be fine

whats the worse that can happen, you will be closer to where you want to be?

mk

littleball_s4

Ride height "unbalance" is unimportant (the amount we're talking about).

Corner weight "unbalance" can be felt in a road car, because the car is tighter to one side. If the car is stiff and quite unbalanced, the difference is noticeable (obviously you need to push hard, but that's what you do when you are concerned about corner weight balancing).

Slantnose!

All that makes alot of sense.
Thanks for all the help & feedback.
Yesterday, tried again & got closer:
LR 943 RF 914
LR 817 RR 927
Stopped as the left rear started going up...over 1/2" higher than the right.
Might try a few more turns today.

John Veninger

Don't forget to get the car aligned again when done!