IcemanG17

My mechanic sent me some corner balance data today....we have been tinkering with the corner balancing on my race 928.....I have always known how light it is...at 2624lbs.....but the balance is INSANE.... Take a look at this....

Of course the weights with my 200+lb self is a bit less perfect....

hb253

Interesting, I always thought it was 50/50, but might that be the difference between regular street setup vs. stripped racer?

jcorenman

The problem is that most of the weight that can't be removed, is in the front. I think stock is something like 52/48 front/rear, but most of the discretionary stuff is midships and aft. When you lighten it, it tends to go bow-down.

James Bailey

Right and 50 / 50 is NOT ideal....You actually want more like 55%,60% on the rear. Which helps explain why 911s have had so much success racing

RKD in OKC

You are supposed to corner balance your race car WITH the weight of the driver in the seat.

Lizard928

Rob Edwards

Not race cars, but datapoints for street cars

Stock GT, 1/2 full tank, otherwise empty. 3505 lbs.

931 943
827 806





GTS, 3/4 tank, my butt sitting in it. 3758 lbs

988 938
942 890

RKD in OKC

WHAT, Not race cars??!?!?!

The ONLY CARS you really need to corner balance ARE race cars. The whole idea behind corner balancing is to setup the car for optimal handling at the limits. Which means driver or approximate weight in the driver's seat and half a tank of gas or whatever the median amount of gas you race with. I don't know about you, but I am NEVER concerned with the handling of my car at the limits when NOBODY is driving it.

My 951 was 51/49 front/rear weight distribution when I corner balanced it (with me in it). I don't remember the exact corner numbers but my mechanic was really proud of the fact he only needed to adjust one corner by 1/16" to balance it. The really interesting thing is the corner balancing took about 2 seconds off my autocross lap times. Before balancing it felt like the car was rocking like a table with a short leg as the weight transferred going into a corner. When at the limit of traction the rocking would break the tires loose at lower speeds. On an autocross course with a LOT of transitions and turns it made a huge difference.

Don't notice it nearly as much on the GTS. Suspension events don't seem to happen nearly as quickly on the GTS as they did on the 951.

Rob Edwards

Oh, I know it's kind of silly for street cars, but A) I was just curious, and B), I drive flat out everywhere I go.

Lizard928

Corner balancing is a good idea on street cars too.
The reason is for emergency situations when the driver has to transition from left to right (or visa versa) really quickly.

JHowell37

And why they've had even more success crashing backwards into the woods.

JHowell37

Actually if you read through the WSM section on alignment, it basically says that the car should be corner balanced prior to alignment. Measuring the ride height is a nice preliminary method of getting it properly adjusted, but the only way to get it dialed in 100% is to put it on the scales and make the fine adjustments from there.

James Bailey

My students at POC ,HPD when I finally let them go out solo comment on how different the car feels Chief driving instructor often comments that he is handicapping someone when he assigns me to their car !! Like here let's see how you do when your car is 10 % heavier.
Note that when you are driving, turning, braking the loads are far different than what you see in a static none moving weigh in. Hard tight corner and the inside wheels get nearly unloaded ( or completely if you screwed up the spring rates) as it runs on the outside tires so much so that you can drive over the rumble strips at the apex and not feel it much. Which means that quite a few pounds difference static is a small percentage in that corner because so much weight has transfered. Sure better to start out as close as you can with a drivers weight in the car but not as critical as it might seem. Just easy to measure and sounds like a great idea.