Corner Balancing Question, With a twist Options

[ellisor3]

I took my car to get it corner balanced, and all seem to work out pretty well. Then went to get the alignment and had some issues. I posted about that and got some really good feedback that will help me solve the problem.

Then today as I was looking at the situation again I noticed another problem. The ride height of my car is higher in the passengers rear than the drivers rear by 2.5 cm. I don't know how I or the shop that did the corner balancing missed it.

Here are the numbers from the weighing

LF 599 RF 541 =1140
LR 724 RR 678 =1402
Total weight 2542
Left side is 52% Right Side is 48% Cross weight is 50.23

To Correct the balancing, take the weight of the total of the front and multiply by the corner to be corrected: 1140x52%=593 for the LF 1140x48%=547 for the RF
1402x52%=729 for the LR and 1402x 48%=673 for the RR

Corrected quadrants

LF 592(-7) RF 547 (+7)
LR 729 (+5) RR 673 (-5)

Since I have steel flares, I measured the height from the floor to the lip of the flares and they are the same.

I also checked the height setting on the shocks (Bilstein Sports) and they are equal to each other.

What would make the car higher on one side?
Could the sway bars cause this?
It seems one option would be to raise the LR to not only equal the weight but correct the ride height. The only thing that puzzles me about that is that the shocks would be set in two different positions, is that normal??

[SirAndy]

Could the sway bars cause this?

I always disconnect the sway bars for corner balance and alignment. They can add preload to your suspension.

Here's a few things:

- Add drivers weight to the drivers seat
- Roughly set rideheight
- Corner balance
- Alignment

If your car sits funny after all that is done correctly, your tub is bent!
BTDT (IMG:style_emoticons/default/dry.gif)

[SirAndy]

If your car sits funny after all that is done correctly, your tub is bent!
BTDT (IMG:style_emoticons/default/dry.gif)

And ... i have the thread to prove it. (IMG:style_emoticons/default/biggrin.gif)

http://www.914world.com/bbs2/index.php?showtopic=50515

[brant]

It might be higher on one corner on purpose
I mean they might have jacked up one corner (or down another) to get those numbers so equal and sacraficed appearance to get it.

i have a car that has been tapped a few times and is not bent, but has a quarter panel put on about 1/2 inch wrong.

I can corner balance the car to get the weight equal as it sits on the contact patches and then the fender looks wrong....

or I can muck with the ride height to get the fender to look correct and then the corner balance is no where near balanced....

my guess is that the car looked good before, and that the corner balance process involves jacking up or down each corner until the weight of the tire on the ground (scale) is equally distributed.... that made your one corner "look" off

if you change the "look" back to before, you loose your corner balance.

A second thing that I've seen/done is to forget to lock the adjuster and have one corner change due to use or vibration and then the car looks jacked wrong.... but it sounds like your had the two process done shortly after each other and probably haven't put enough miles on it to vibrate out of adjustment yet.

brant

[drgchapman]

Could be a bent tub.
Been there done that.

[TravisNeff]

It would be more accurate to measure from the ground to the donuts, rather than the fender lip opening.

[brant]

It would be more accurate to measure from the ground to the donuts, rather than the fender lip opening.

especially on a car that has had flares added.
the car could of been sitting wrong (anything... corner balance, low tire, sway bars) at the time the flares were installed meaning your fender appearance was set on wrong

the donuts are prettty good.
I use the front adjustment bolts on the front measurement

[SirAndy]

It would be more accurate to measure from the ground to the donuts, rather than the fender lip opening.

especially on a car that has had flares added.
the car could of been sitting wrong (anything... corner balance, low tire, sway bars) at the time the flares were installed meaning your fender appearance was set on wrong

the donuts are prettty good.
I use the front adjustment bolts on the front measurement

(IMG:style_emoticons/default/agree.gif)

[ChrisFoley]

Don't ever take a 914 to that shop for alignment work again!

BTW, after changing so many things to accomplish the alignment, the corner weights should have been rechecked.

[stewteral]

I took my car to get it corner balanced, and all seem to work out pretty well. Then went to get the alignment and had some issues. I posted about that and got some really good feedback that will help me solve the problem.

Then today as I was looking at the situation again I noticed another problem. The ride height of my car is higher in the passengers rear than the drivers rear by 2.5 cm. I don't know how I or the shop that did the corner balancing missed it.

Here are the numbers from the weighing

LF 599 RF 541 =1140
LR 724 RR 678 =1402
Total weight 2542
Left side is 52% Right Side is 48% Cross weight is 50.23

To Correct the balancing, take the weight of the total of the front and multiply by the corner to be corrected: 1140x52%=593 for the LF 1140x48%=547 for the RF
1402x52%=729 for the LR and 1402x 48%=673 for the RR

Corrected quadrants

LF 592(-7) RF 547 (+7)
LR 729 (+5) RR 673 (-5)

Since I have steel flares, I measured the height from the floor to the lip of the flares and they are the same.

I also checked the height setting on the shocks (Bilstein Sports) and they are equal to each other.

What would make the car higher on one side?
Could the sway bars cause this?
It seems one option would be to raise the LR to not only equal the weight but correct the ride height. The only thing that puzzles me about that is that the shocks would be set in two different positions, is that normal??

--------------------------------------------------------
Hi ellisor3,

I’m GLAD to see another 914 owner bring up the topic of CORNER WEIGHTING!!! For starters, the shop who “corner balanced” your car SUCKED! While my car is a V8 conversion, I was still able to balance the front Rt to Left at 30 lbs and the Rear as 25 lbs Delta, right to left!!!! You should be able to match this or BETTER!

I honestly don’t know what the “corrective calculations” are about as it all comes down to the weight EACH wheel loads. When I raced a Formula Ford, I just put a bathroom scale under each wheel to do corner weight checks.

To start the process, load WEIGHTS in the driver’s seat AND floor to match the driver (generally, legs & feet = 30 lbs). I do NOT disconnect swaybars as I'm looking for the most TRUE data as possible.

Then, jack up the car, set 3 corners on pads (wooden blocks) to match the height of the measured wheel. Now you are ready for the tedious work of weighing each wheel and carefully making small adjustments.

My car has “adjustable” coilovers in the rear, but each adjustment is ¼” at a time. You should be able to make decent adjustments with the stock the coil-over via shims. In the front, we all can enjoy the wonderful adjust-by-bolt design giving us infinite adjustability.

My “measuring tool” is a simple lever arm I made from some sections of tubing I welded together for a 5:1 ratio. At the outer end of the “Lever Arm” I placed a simple bathroom scale. Start at a corner and record all the corner weights and
when done, you will have a base-line of data from which to start. Then, make a SINGLE adjustment and measure ALL 4 corners again. Make SMALL adjustments and repeat the process until you feel you have gotten the best results possible.
At the end, you will know what I mean about a commitment to do the job. Obviously, the Shop did NOT have a similar commitment.

Check out my Simple "lever-arm tool" which you could match with an aluminum ladder or similar thing.

If you have any questions, feel free to inquire.

Best,
Terry

[brant]

Terry,

there is such a thing as optimum, or target corner weights using a formula to convert the raw numbers you begin with.

[ChrisFoley]

...
I do NOT disconnect swaybars as I'm looking for the most TRUE data as possible.
...

Well that doesn't make any sense at all.
With the anti-sway bars connected one could unknowingly be forcing the springs/torsion bars to compensate for a preloaded anti-sway bar, which will cause the handling to be different in left vs right turns.

Disconnect one end of the anti-sway bars.
Get the TRUE cornerweights within the desired spec and then adjust the sway bar drop links so the bolts slip in and out with no effort.
If the drop links aren't adjustable one would be just wasting time trying to set the cornerweights to a tight tolerance.

[PRS914-6]

I highly recommend that you find a way to make the car "float" when you are aligning or corner balancing. Every time you jack up the car for an adjustment or make any adjustments at all it takes away the natural relaxed setting of the car and it does effect the balance significantly. If you notice, when you jack up the front of the car, the camber changes dramatically and when you set it down it stays that way until the car gets moved. This is bad, it effects height adjustment, alignment settings as well as corner balance.

The best way is to get some ball bearing alignment pads and set them on your scales. These allow the car to completely float on top of the scales. If you need to jack or adjust anything, the suspension and tires can move around freely. The ball bearing plates are nice as they are restricted to about 4" of movement preventing the car from sliding off the scales. I don't care for the 1 scale approach due to the variables and extra work.

The "cheap way" is to get 8 pieces of sheet metal about 12" square. Grease between two sheets and install between the scales and tire. This allows the suspension to float. IF YOU DON'T LIMIT THE CAR TRAVEL IT WILL SLIDE RIDE OFF THE SCALES!!!!

If you have adjustable shocks, set the damping to the lowest position while balancing

Like Chris said....disconnect any sway bar. Re-assemble when done without any bind by adjusting the downlinks.

After any adjustment give the bumpers a couple of pushes to "settle" the suspension

Small adjustments and check. You will have to go back and forth between alignment and corner balance until things get pretty close as one effects the other. It's frustrating and time consuming. Dedicate a day your first time.....Don't forget to properly inflate the tires before starting.

[stewteral]

Terry,

there is such a thing as optimum, or target corner weights using a formula to convert the raw numbers you begin with.

Hi Brant,

Can you explain your approach? I simply adjust to get the small delta of weight, side to side.

Best,
Terry

[stewteral]

...
I do NOT disconnect swaybars as I'm looking for the most TRUE data as possible.
...

Well that doesn't make any sense at all.
With the anti-sway bars connected one could unknowingly be forcing the springs/torsion bars to compensate for a preloaded anti-sway bar, which will cause the handling to be different in left vs right turns.

Disconnect one end of the anti-sway bars.
Get the TRUE cornerweights within the desired spec and then adjust the sway bar drop links so the bolts slip in and out with no effort.
If the drop links aren't adjustable one would be just wasting time trying to set the cornerweights to a tight tolerance.

Hey Racer Chris,

I won't argue the point of disconnecting swaybars as a way to be sure additional loads are being added by them. In my case, I carefully had all 4 wheels at the exact same height and knew my swaybars had no pre-load.

Best,
Terry

[stewteral]

PRS914-6

Hey Paul,

With that $1200 equipment you RULE when it comes to adjusting corner weight!
....Any chance I could borrow it? (IMG:style_emoticons/default/smile.gif)

Of course, you are right about changing the chassis set whenever a wheel is jacked up. With my set up, I'd change the measured corner, reset the blocks under the other wheels so the car was at the exact height all around . Next I rolled the car back and forth to settle the chassis to its true ride height and THEN measured the corner weight.

It was a very LONG and tedious process and took me 1-1/2 days to get it done.

Enjoy your Toys!
Terry

[tradisrad]

I played with cormer balancing my car with Ruggle style scales. I found that I had to move the spring height quite a bit to get the weight shifted and the result was a car that did not sit evenly. the car was fairly well balanced w/o my weight, but once my weight was added I really had to change the ride height.
I figured it was due to my "low" spring rates of 150lb and I stopped the process and adjusted my car to sit evenly and I have not gotten back to playing with it.
Is it true that with higher spring rates it takes less movement to shift the weight?
What set suspension set up are you using?
Here is a link to the post I started.

[brant]

Terry,

there is such a thing as optimum, or target corner weights using a formula to convert the raw numbers you begin with.

Hi Brant,

Can you explain your approach? I simply adjust to get the small delta of weight, side to side.

Best,
Terry

Terry,
I won't probably do justice to this topic
basically any production car has a fixed handicap and you can only work within the basic limitations of the design... (ie: we don't have center seating or a 911 has the heavy weight of an engine in the back and these are fixed properties you have to work with)

So within the fixed properties of the design you can use the "ideal" formula to calculate what the ideal weight of any corner should be and still maintain your percentages.

I told you I'm not doing this justice...
but if you corner balance to the ideal's the car is more balanced.
I have also noticed after doing this for about a dozen years.... that when you actually hit the car's fixed ideal's the scales will show a weight loss.... presumably because the balance is more perfect. I know it does not make sense, but I often find that my car's total weight (all 4 combined) will go down around 10lbs as I tune to the ideals.

I always get my race car within 1 pound of its calculated ideals. I re corner weight once a year or more often if I have suspension damage or reason to rebalance.

here is a link I found with a quick google search that can better explain
reading fred puhn's book will do this subject more justice than I can

weight jacking

[jmill]

For the DIY guys don't forget to level the floor. I use cheap stick on 12"x12" bathroom tiles and plywood. Mark the floor where the tires will be. Move the car out and stack up tiles and plywood until it's level side to side and corner to corner. I had a great set of Longacre scales but sold them with the racecar. (IMG:style_emoticons/default/headbang.gif)

[ellisor3]

So based on what I have read and using my example I should start by raising the largest discrepency quadrant that is negative to ideal first? In my case that would be the left front. It seems that raising the left front would push down the right rear. What am I missing?

Ideal numbers and the change needed in parenthesis

LF 592(-7) RF 547 (+7)
LR 729 (+5) RR 673 (-5)