Corner weights

After more than a year since starting a new job I dug my car out and started working on it again.

Car is biased pretty heavy on the left side

LF 642 RF 587
LR 567 RR 512

This race ready including driver less fuel and transmission oil.

I have set ride hts the same on both fronts ( 3.5 )and both rears ( 4.5).

Should I be concerned about being 50 lbs light on the right rear ?

I've always had the best results with either equal rears or about 20 lbs heavier on the passenger side, if it was mine Id get some fuel in it and adjust torsion bars with driver in car, for close to equal weights in rear. Always worked best me, Im running a leaf spring car with Caltracs, had it set up the same way with the Launcher springs before, Good luck with it

I've seen those ratio many times on many BB Mopars, A,B and E bodys Is the battery mounted on the right side as far back as you can get it? If not try that as the first step. The car should be bettr with more weight on the right rear than the left rear so see what you can do including adding ballast back there Let us know your results please

The car is 200 lbs heavy on the driver's side, and 75 lbs heavy on the front on both sides if you look at it that way. The front to rear is about the same percent on either side. You could start there, and add a touch of weight if it goes right on launch. Maybe even start by moving 10 from drive to pass side.
What was it before?

I try to build the car with right side weight bias. A non chassis car is hard to get even right to left. That being said you adjust the car to leave straight. The actual rear cross weight numbers aren't the telling tale, it's how the car leaves. I've found a 10 second car can generally be uneven w/o issue. When it starts to leave harder it becomes a bigger issue. I'm talking stock chassis cars here. The trouble with adding right rear weight is that the front right to left bias becomes greater. A hard stab at the brakes in the lights can be a surprise. Just as adding weight to one side of the rear helps the greater spread in the front can cause issues as well, tread carefully. Here was the scale numbers from mine. As you can see I worked very hard to get the right to left bias close. When the initial testing at the track was done it still needed 3 flats of additional preload to run straight

LF 926 RF 878

LR 745 RR 764

Front 1804lbs 54.5%
Rear 1509lbs 45.6%
Cross 1623lbs 49%

Total 3313 lbs w/me
Doug

Tried to put as much on the rights side of the car as practical but hard to compensate for my weight in the drivers seat. I will have to see what else I can move over. Won't be able to be complete and test until next spring as time and money permits but happy to find time to start to work on the car. Thanks for the advice.

What suspension front and rear??

Its a full chassis car so strut front and four link rear.

Then you need to take a hard look at whats going on there. Certainly don't want the rear weights where they are at now IMO. Assume all this was witht he 4 link set to neutral(no preload) and all the spring heights at each corner equal, ie springs all have the same amount of preload. One other important thing people overlook is make sure you have the tire pressure where it will be raced. A pound of air can move corners weights around pretty significantly.

How fast? ET? 60'?

I did not check tire pressures thats a good suggestion thanks.

How fast, dont know yet but I have a couple of motors and the first one is B1 deal so it will start out as a 8 second car and down the road I have a boosted motor to install.

I also heard back from a friend with a TS car that has run 6.86 and he told me that with his car he is not concerned with corner weights and the set up is focussed on ride hts and the front rear bias. His explanation to me was that corner weights go completely out the window at launch.

Then he started talking about the rear steer in his set up and lost me... I have quite a bit to learn.

I just caught the part about you figuring it will be an 8 sec ride, with more to come. IMHO,get as much weight to the pass side as you can to get closer to even, then get it scaled by a chassis builder that races or crews for a car fast as or faster than what you are planning on. I went to a local guy that built chassis and was running a shoebox Chev, deep into the 8s, best money I have spent. The first trip to the track and I had to change one side of the wheelie bars by a 1/4 inch, and it launched dead perfect.

One thing with chassis weight.. you end up adding pre-load
to make the car launch straight... so if you add a lot to
over come the weight being in the wrong places... but when
you add pre-load it will do the opposite thing on shut down..
when you snap out of the pedal it will tend to go left... and
if you have a lot of load it really wants to go left... get the
corners close with everything at zero(pre-loads and anti roll)
then once you get your corner weights close then add the pre load
and keep the anti roll at zero... pre-load is based more on the
torque you have... a ton of torque will try to drive the car to
the right so you have to add more pre-load to counter the torque
REMEMBER TO HAVE THE CAR AT RACE WEIGHT AND THE DRIVERS WEIGHT IN
THE CAR when you start playing with corner weights and pre-load
EDIT
On my 4 link and anti roll bar I will disconnect the upper right
bar(I pull the bolt on the front of that bar)till I get the weights
to where I want... otherwise you keep chasing the bar loading up
as you move weight... then the last thing is to hook up the anti
roll bar... I use zero lad there

My car weighs within 10 lbs of yours. Mine is almost 150 lbs heavier on the left front than the right rear like yours. I think this is all normal. The motor is in the front and the driver sits on the left so the weight is where it is like most every other race car. My car launches fine and I think yours will too. I believe you are over thinking this.

https://vimeo.com/44009973

P.S. If you are going to have a chassis car read Jerry Bickel's book and Rick Jones' book.

If I were involved in this, I would want to see the RR a bit heavier with the driver in the car. Maybe equal to or just a few pounds lighter than the LR. Without the drivers weight in the car, I would expect the RR to be at least 20 or 30 pounds heavier than the LR. This will certainly cause the LF to be heavier than the RF. Moving the weight can be accomplished a number of different ways. 4 link preload, spring height, moving ballast, a combination of any of those, etc. Unsprung wheelie bars are also a tuning tool.

Many things influence this. Torque and power levels, trans type and gear ratio, 4 link geometry, spring rates, etc. Consider the initial set-up to be a baseline intended to get the car down the track. Adjustments, based on what the car does, can be made from that point, but you need to know where it is initially. If the weights are close, the car should go reasonably straight. If it tries to run over the tree, something else is wrong.

Both of those books are well worth having.. I have them and
a couple others... when I built my car(and a few others) the
corner weights came out very close.. even with me in the seat
(within 70# but I weigh parts before they get put in... and I
will move the engine/trans to help this issue.. my car front/
back bias is 48/52 with me in the seat... its 50/50 with out me
EDIT
The pre-load on the 4 link is 18#... this thing drives arrow straight
all the way down track... as in hands free... I had the steering
wheel pop off one time and I got it back on at about 300' out and
still got that round win

I don't post here much, but here are the numbers on my Avenger
Things I have learned about setting up four links:
Ride heights exact
Tire pressures exact
All front end alignment settings set
Race weight , driver, fluids
Pinion angle set
Top right link disconnected or zero preload
Disconnect anti roll bar
Scale it ( Be real sure the scales are level side to side front to back. This is critical)

I follow the Rick Jones and JBRC recommendation of having 40-60 lbs heavy on LR and set the car up that way

I then set zero preload on the four link and ARB. Occasionally I have to add a flat depending on track conditions. Drives straight as a string.

Very helpful and informative, thanks for all of the advice. I think I will pick up a chassis book or two and more importantly complete this car.

Would like an update on your first passes and how you set it up

Will do but will not be till next spring.