Unloading the rear tires

[Slow91z]

Correct me if I'm wrong fellas but in my understanding it's not as simple as relocating the uppers or the lowers...everything has an effect on this, like ride height, how hard your car hits the tires (transbrake, footbrake, how much boost ect) weight, weight distribution...what works fors your car Kevin might not work as well for John's car and vise versa.

To the original poster, John all I'm saying is there isn't an easy answer to your question.

 

[Blazer406]

This is gettig OT, but how can you argue that the buckets (with non stock mounting points) and matching arms fall under "stock locations"?

I will agree you can change the way a car hooks/squats by changing the instant center.

I also agree if you are unloading the tires 20' out, there should be a shock/spring combo with proper settings to help this. The front end is probably rising too quick and the car isn't making enough power to hold it up, so it is coming down too quick and unloading the rear tires.....

 

[Alky V6]

The problem with having a squatting problem is that whenever you increase power to the drivetrain, the rearend will want to pull up into the body. Another way to say it would be, the rearend wants to pull up off the track.
If you are anywhere on the track and you increase power, such as have the boost ramp up drastically at a point, then the tires will tend to pull away from the track, versus wanting to plant into the track, which is more preferred.

 

[KevinB]

Because the buckets bolt to the stock location, and arms to them. I've never read about or seen someone being ejected from a class because of these or the southside brackets.. I see it as OK. If not, then the southside bars would be considered illegal too.

 

[Alky V6]

This reminds me of a Chevelle I was watching at the track. BBC with a couple stages of nitrous. He was having traction issues when a stage of nitrous would come in. I went over to his pit spot and peaked under his car. The instant center was off in a way that would encourage the rearend to pull up when a large amount of power was suddenly applied. I gave him some tips and he made some changes before going out again. I met him in the pits later, and he was surprised by how much of a difference that adjustment to the IC made. Don't ignore the IC. It's very important.

 

[Alky V6]

Correct me if I'm wrong fellas but in my understanding it's not as simple as relocating the uppers or the lowers...everything has an effect on this, like ride height, how hard your car hits the tires (transbrake, footbrake, how much boost ect) weight, weight distribution...what works fors your car Kevin might not work as well for John's car and vise versa.

To the original poster, John all I'm saying is there isn't an easy answer to your question.

As power levels increase, you're right that all the particulars of chassis setup become more critical and picky, but for the lower power levels, just getting the IC into the ballpark will work wonders. The stock IC setting on the G body is way out of the ballpark.

 

[Alky V6]

Don't use spring and shock settings to bandaid an IC that is way whacked out (stock IC). At least get the IC into the ballpark. At lower power levels, the IC location is not super critical, but it should be in the ballpark.
Get the IC into the ballpark first, then spring and shock settings.

 

[Alky V6]

Next time you go out, put the front shocks in the middle. You want to keep as much weight transfer on the rear wheels. When the cars front end pops up real fast and falls back down at the same rate, all that weight transfer goes back to the front, unloading the rears.

On the squat issue, if you look at my pic in my signature, that was before i put the relocation brackets on. Now the clearance between the tire and fender do not change. The good thing about the baseline kit is it adjustable. You can have too much lift, where the rear if the car will separate from the tire, but there are 3 adjustments to get it right. I use the top hole. Haven't had time to plot it out yet but it works great.

I noticed that with your sig picture. I just assumed it was a before pic. I was hoping it was a before pic.

 

[Alky V6]

Not to contradict everyone but I am using relocation brackets on the rear end lowers. Been 1.25 60ft on 275 radials. They are supposedly better suited for slower cars.

Lowering the rear of the lowers would tend to really put some anti squat into the chassis. As long as you're at a power level that doesn't smash the rear sidewall too badly, that would be alright.
As I mentioned earlier, trying to keep the lower control arms level to the ground is also a stability concern. During hard braking, the rear axle would tend to want to pull up into the body with the lower control arm heavily angled like that. If you notice that you lose traction to the rear tires during sudden hard braking, you may want to change the lower control arm angle back to close to level.

 

[Slow91z]

As power levels increase, you're right that all the particulars of chassis setup become more critical and picky, but for the lower power levels, just getting the IC into the ballpark will work wonders. The stock IC setting on the G body is way out of the ballpark.

I'm not disagreeing with that (although i have seen cars work really well with the stock suspension geometry) all I'm saying is not every one of the cars we are talking about will need exactly the same stuff.

 

[KevinB]

I'm not disagreeing with that (although i have seen cars work really well with the stock suspension geometry) all I'm saying is not every one of the cars we are talking about will need exactly the same stuff.

What's the best 60 with stock geometry you've seen? Remember, if the car has a 9", usually the mounting points for the upper control arms are raised.

 

[Slow91z]

The 2 cars that come to mind that are similar to the OP's goals and power levels go mid and low 1.4's one on radials.

That would definitely be enough for John's goals at the moment...I'm not saying it's optimal, 1 is a very consistant car and the other might be constistant it just hasn't gone down the track enough to know it's limits.

 

[Alky V6]

Well, if you had to use the stock IC setting, I would think you would want to pump up the compression setting on the rear shocks to keep the rearend from wanting to suck up into the body during shifts. Stiff springs to slow down suspension reaction might help too.

 

[Alky V6]

The IC setting is a pretty primary setting. If that is wrong, you're pretty much using all the other settings to bandaid the bad IC.

 

[Slow91z]

No fancy shocks or springs on the rear of the car's I'm referring to either, just aftermarket arms and HR bar and no air bags.

 

[Blazer406]

I know of a car that has gone 1.2x's with stock mounting points.......and the 8-1/2" 10 bolt rear too.... There are plenty in the low 1.3x's.

Again, I'm not saying that the stock IC is optimized, just that it appears to work pretty good in some cases.

 

[Slow91z]

Now that's moving

 

[Alky V6]

Let's hope the OP can be one of the lucky ones that makes the stock suspension work out for him.

 

[charlief1]

The stock suspension wasn't designed for peformance as much as comfort to the riders of the car. The fact that it's done as well as it has really tells you that it can be improved without sacrificing the comfort of the passengers. If you're willing to do this it will help traction and get you better times on the track. You have to remember it's simple geometry of the parts as well as motion function. As the tires grip and go foward the axle spins the other way using the rear control arms like levers. If you change the positions of the levers you can gain an advantage in torque to the chasis as well as allow the weight transfer.

Donnie learned more about this in the last year with the relocation brackets that he got from Kevin. With those in place his launches have gone from violent, to as he put it, boring. But it's helped him to make the car more consistant which is what it's all about.

 

[Kellysgn]

Technically I think the baseline buckets are considered stock location because they bolt into the stock location and the arms bolt into them.

The Baseline buckets , are they compatable with H&R adjustable uppers ? thank you