Total Lateral Load Transfer Distribution

[iadr]

I'm reading, watching, but off the top of my head pre morning coffee, I don't have much input.



Thought experiment- what happens if you go to a stiffer front spring, and hold the car-as-a whole, flatter with that. Theory says should increase push, right? What if it doesn't actually do so in practice? I think your odds are better than 50-50.
Can you explain your taking out the .9" tall balljoint in favour of a .5" tall one? I trust you give your set up much more thought than I can just walking in here, but it is also true that you felt (and I agree) that that meant a need for more static neg camber, and also that you now note the outer tire is in need of more neg from somewhere ( maybe caster is a last grasp option?). Basically, in following the saying, "you don't understand something fully until you have to explain it", can you throw out a few sentences on what change in feel you aimed for, and consider if you got it?
I'd have lowered the front end at that point- cut say a quarter of a coil off- you'd change the turn in, get your rear end looser, and get deeper into the camber curve. Not by large amounts of any, but all factors are directionally the same so add up. That is definitely "hack"..., but this is a car that despite all the work and thinking we do in this "niche" of performance, has only a fair to middling and largely unchangeable geometry set, by definition. At an OE or custom suspension level, I think playing with rear roll center at that point might have helped, so what do you have you can do with stock rear parts? I'm not a Camaro guy- you do have a panhard bar in these, right?

[Sleeper68]

Thank you for the reply iadr; I appreciate it. To answer your questions:

Thought experiment- what happens if you go to a stiffer front spring, and hold the car-as-a whole, flatter with that. Theory says should increase push, right? What if it doesn't actually do so in practice? I think your odds are better than 50-50.

Keeping with the theory I have, the car would push more, likely everywhere. Not particularly easy to do on my car; however, with easily changeable jounce bumpers (instead of ride springs) I could try a stiffer front end. Not sure what you mean by the odds are better than 50-50 - towards more understeer or towards more oversteer with more front spring?

Can you explain your taking out the .9" tall balljoint in favour of a .5" tall one? Basically, in following the saying, "you don't understand something fully until you have to explain it", can you throw out a few sentences on what change in feel you aimed for, and consider if you got it?

SETUP 1: The first significant front RC change I did was achieved by going to a 0.9" tall upper ball joint from a factory one on otherwise stock geometry (raised roll center ~ 1.25" and made camber gain negative instead of positive - 0.3°/in). This was in 2015. -3.0° camber , +6.0° castor , 0.0" toe

SETUP 2: The second front RC change was done in 2020 by lowering the inner pivot of the upper control arm about 1/2" rear hole 5/8" front hole (raised front roll center ~1.1" and made camber gain more aggressive 0.8°/in). This also had the effect of reducing front anti-dive since it is fairly excessive in first gen camaros. The reason for the second change was because I found I had to run alot of front camber (2.7°-3.0° neg) to keep the front tires happy but this came at the cost of poor front end grip in braking. I attributed this poor braking performance to the excessive static camber after playing with brake pressure proportion (ended up with full bias to rear tires in braking, still locked up front tires with even small amounts of trail brake). The idea was to increase camber gain and thus reduce the need for static camber. The inadvertent effect was a stiffer front end due to the higher front roll center. -1.5° camber , +6.5° castor , 0.0" toe.

SETUP 2.5: Rear RC moved up to 13.5" from 12.5". Rear ARB endlinks changed to rod end style from polyurethane-bushed style. -2.0° camber , +6.5° castor , 1/8" total toe out

SETUP 3: The third front RC change was performed in 2021 by going to a 0.5" tall upper ball joint from 0.9" tall (lowered front roll center ~0.5" and made camber gain less aggressive - 0.6°/in). This change was made in an attempt to "split the difference" between change one and two. This height jived with the rear RC height of 13.5" quite well for the roll stiffness's I have been able to achieve with my current springs and bars. The rear is as stiff as I can get it with the bars, leaf springs, and rear RC I have. -2.1° camber , +6.7° castor , 1/8" total toe out.

As far as I can tell, each time I raised the front RC, the car pushed more, anf the front was stiffer. Each time I raised the rear RC, the car pushed less and the rear was stiffer. The time I lowered the front RC, the car pushed less and the front was softer - up to a point. The point appears to be where the outside front jounce bumper starts to really "come on" and become really stiff. The jounce bumpers can be thought of as progressive rate springs.

I trust you give your set up much more thought than I can just walking in here, but it is also true that you felt (and I agree) that that meant a need for more static neg camber, and also that you now note the outer tire is in need of more neg from somewhere ( maybe caster is a last grasp option?).

The car wanted a certain amount of dynamic camber relative to the ground. The RC adjustments were preformed in an attempt to achieve this dynamic camber setting with LESS static camber. So far the adjustments have been semi-successful, but I appear to have been limited by the lack of rear roll stiffness - mainly due to a lack of rear ride stiffness (approx 1.4Hz / 175lb/in rear, front is 1.5Hz / 600lb/in).

I'd have lowered the front end at that point- cut say a quarter of a coil off- you'd change the turn in, get your rear end looser, and get deeper into the camber curve. Not by large amounts of any, but all factors are directionally the same so add up. That is definitely "hack"..., but this is a car that despite all the work and thinking we do in this "niche" of performance, has only a fair to middling and largely unchangeable geometry set, by definition.

What is your rationale that lowering the front end will get the rear looser other than increasing front dynamic camber? I have heard other people mention lowering the front to help with push. Unfortunately, the car would be very low and would scrape everywhere if I lowered the front much more. Could the same thing be achieved by raising the rear?

At an OE or custom suspension level, I think playing with rear roll center at that point might have helped, so what do you have you can do with stock rear parts? I'm not a Camaro guy- you do have a panhard bar in these, right?

The car has a rear Watt's link. They (1st gen camaros) do not come with a lateral axle locating device from the factory actually. This is a aftermarket unit from Jim Fay (Fays2). I did actually adjust the rear RC in proportion to the movement of the front RC from setup one to setup two and it helped but was not enough. The rear RC is as high as it will go without some fairly significant fabrication.

Thanks again for the reply. Love to have discussions like these. Other people's perspectives can really open your eyes.