Tom Tweed

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by DJF1:
<strong>Something important that is not mentioned here is the need to have the driver in the driver seat and the car in "racing trim" with the average fuel on, tires etc when the corner balance takes place.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Yes, this is a given, and swaybars should be disconnected so as not to introduce any preload on a corner. When reconnecting afterwards, droplinks should be adjusted for 0 preload.

TT

RS racer

Thanks for the good feedback.

This may be getting to detailed for the site but these are my latest corner wights with me in the car (185th lbs.) I put additional fuel in the car to make race weight.

LF/RR RF/LR

1360 1527
47% 53%

Are these ratios close or should I try to get it spot on?

RS racer

I should of included my L R totals as well.

LF/RR RF/LR
1360 1527
47.1% 52.9%

L R
1477 1410
51.2% 48.8%

911pcars

RS Racer,
Can you give us the corner weights as well?

Try Tom's formula: LF/LR = RF/RR

This formula is most applicable to cars that don't have exact side-to-side weight (as in most street-based cars with drivers on one side). The object is to get the front-to-rear proportions as close as possible on each side. However, in so doing, you may end up with slightly different heights at each corner (front and rear end).

When doing it in this manner, the diagonal weights should be close, but not exact. A single seater symmetrical race car is more apt to approach the ideal.

Here are a few corner balance forms/calculators that will help establish/adjust/keep track of the desired corner weights.

Sherwood Lee
<a href="http://members.rennlist.org/911pcars" target="_blank">http://members.rennlist.org/911pcars</a>

RS racer

LF 656 RF 539

LR 821 RR 871

This is with me in the car (185lbs)

Greg Fishman

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by RS racer:
<strong>LF 656 RF 539

LR 821 RR 871

This is with me in the car (185lbs)</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">That seems way off, your cross weights are 1360 and 1527. Needs to be re-balanced if you ask me. I am usually within 40 lbs across the front and the same on the cross weights.

911pcars

RS Racer,

LF 656 RF 539
LR 821 RR 871

Those numbers put you at:
Left side = 79% f/r ratio
Right side = 61% f/r ratio

I would suggest raising the LR and RF corners. That should add weight to these corners and reduce the weight of the heavier LR and RR corners. Alternately, you can reduce the height of the LF and RR to transfer (add) weight to LR and RF

Sherwood

911pcars

I shouldn't confuse the issue with typos. Here's what I meant:

"I would suggest raising the LR and RF corners. That should add weight to these corners and reduce the weight of the heavier LF and RR corners. Alternately, you can reduce the height of the LF and RR to transfer (add) weight to LR and RF."

Sherwood

Randy

Depending upon what margin of error you are willing to accept, DE participant, club racer, etc..., the importance of measuring corner weights on a perfectly level surface should not be underestimated. Ideally, a person will use scale pad levelers that have been leveled to each other side to side, front to back, and diagonally both directions. If you don't have these resources, an option is to use the same exact spot on your floor each and every time you scale, otherwise there is no consistent reference point and the numbers are essentially meaningless if you use crossweights as a tuning tool. It is also very important to have the car in exactly race ready condition; driver in seat or representative ballast, chosen fuel load(consistent), full alignment/ride height set and tire pressures exactly set. Only then will the numbers mean anything. I scale a race car weekly and I'm looking for a very specific percentage each time that varies. The margin of error I try to achieve is .5%. I can tell you from personal experience that changing the tire pressure in one tire on one corner by only 1 p.s.i. will change the crossweight percentage by nearly 1.0%. A person also needs to remember that every new tire is a little different circumference as well, which effectively makes the old settings irrelevant, bias ply tires more so than radials. I race a lot on ovals, which requires a wacky setup, and I can change the handling of the car significantly with a 2.0% change in crossweight. Now, for DE participants and casual club racers, an even percentage is probably good enough. This would be 50/50 LF+RR=RF+LR. It is more important to have even percentages, IMO, than even corner side-to-side weights on the front or rear. If there is a large difference in weights side to side in the front or rear, moving your battery around, or some other semi-"live" load to even out that difference is a better strategy than compromising the crossweights to achieve an even wheel loading side-to-side. In a chassis where the driver is offset, the side to side percentage will always be biased, but that is a common liability "in class". With even crossweights, the individual corner weights will likely never be similar. Now, weight jacking can, however, be a very effective tool to enhance the cornering capability when used carefully under the circumstances where a track has significantly more left turns or right turns, and the characteristics of the turns are suitable. Carrying more weight across the RF and LR will make a car turn better to the left, LF/RR, it will go right like gangbusters. Obviously, you have to set the sway bars each and every time. If a track has mostly left turns, like Pacific Raceways, you can use a little weight jacking to maximize the turn speed through 2, 3b, 5a, 6, 7 and 8, so long as you don't destabilize the car on right turns so that you can't get around 9(the most important before the longest straight) well enough to get a good drive down the straight. That's what I heard somewhere anyway..