STX Rules and Setup Questions

[steverife]

Originally Posted by M0nk3y

You're stuck in SSC land though...

I grabbed an X magnet off the ground working course, put it in my pocket, then forgot about it until I unpacked my rain gear a few weeks later...

...so my build has started!

[M0nk3y]

Originally Posted by steverife

I grabbed an X magnet off the ground working course, put it in my pocket, then forgot about it until I unpacked my rain gear a few weeks later...

...so my build has started!

Atta boy. Hit me up if you need help. Can at least explain where I got to where I am setup wise


Sent from my iPhone using Tapatalk

[bmacfrs]

Corner weight balancing. A maddening process after hours of adjustment and checking results. This is the closest to 50% cross I have been able to get. Its way better from where I started. This is with my weight and race prepped. I'm not sure about the wide difference in weights from wheel to wheel. But the car is front heavy and obviously to the drivers side. so i guess that makes sense. It should be better handling though with the cross balance closer.
what do you think?

[H1C]

Originally Posted by bmacfrs

Corner weight balancing. A maddening process after hours of adjustment and checking results. This is the closest to 50% cross I have been able to get. Its way better from where I started. This is with my weight and race prepped. I'm not sure about the wide difference in weights from wheel to wheel. But the car is front heavy and obviously to the drivers side. so i guess that makes sense. It should be better handling though with the cross balance closer.
what do you think?

You got your cross weights closer to ideal than I did.



FWIW this is the most helpful explanation that I've encountered of what the goal of corner balancing is:


https://www.elephantracing.com/tech-...orner-balance/


"The goal of corner balancing is to have the same front-to-rear weight ratio for both left and right sides. Expressed as an equation. How to corner balance your car



This equation works for real-world cars that are asymmetric. With this equation in balance, the car will handle the same through left and right turns. That is the goal.
Notice that if the car is symmetric the diagonal weights targeted by the Corner balance equation are equal! If the car is asymmetric, the targeted diagonal weights are not equal."


Attached are what my corner and cross weights were, both empty and with me (146 lbs) in the car. The car had nearly a full tank, lowered with 0 rake F to R and around a 2 finger gap in the rear, and maybe a little more than that in the front.



The front spring perches are lowered an equal amount. The RR spring perch is lowered 2 mm more than the LR spring perch, to compensate for the fact that it sat a little higher when the perches were lowered equally. RCE Andrew pointed out in his suspension Q&A thread that all Subarus are a little light in the RR, so the RR will sit higher than the LR if their perches are adjusted to the same height.



These weights were as the car was, without making any adjustments. The LF/LR = RF/RR equation was so close, both empty and with me in the car, that I decided not to try to chase a perfect 50% cross weight (RF + LR)/total weight. The shop owner said it was the best balanced car off the bat he had ever seen, and agreed that it wasn't really necessary to chase a perfect cross weight, if I was happy with the ride heights and how it handled.

[bmacfrs]

Originally Posted by H1C

You got your cross weights closer to ideal than I did.

These weights were as the car was, without making any adjustments. The LF/LR = RF/RR equation was so close, both empty and with me in the car, that I decided not to try to chase a perfect 50% cross weight (RF + LR)/total weight. The shop owner said it was the best balanced car off the bat he had ever seen, and agreed that it wasn't really necessary to chase a perfect cross weight, if I was happy with the ride heights and how it handled.

Was that with coilovers set to relatively even ride heights? Why was yours so close already?

I did what it think most do when installing the coilovers. I set the heights so the car was about an inch lower, even from left to right, and slightly lower in rear. Measured from fender edges to hub center and pinch welds to ground. When I put it on the scales, with my weight and fuel, the numbers were all over the place. the cross was 45%.

Now, i'm a 3/4 inch difference from my lowest fender measurement to the tallest. Seems like a lot of variance to me.

[dutchman1]

Originally Posted by bmacfrs

Was that with coilovers set to relatively even ride heights? Why was yours so close already?

I did what it think most do when installing the coilovers. I set the heights so the car was about an inch lower, even from left to right, and slightly lower in rear. Measured from fender edges to hub center and pinch welds to ground. When I put it on the scales, with my weight and fuel, the numbers were all over the place. the cross was 45%.

Now, i'm a 3/4 inch difference from my lowest fender measurement to the tallest. Seems like a lot of variance to me.

Weird, I set my coilovers even side to side, and about 3/8 lower in the rear. First time on the scales was 50.7 percent cross. That's with a 250lb driver and 6k/7k springs.

[H1C]

Originally Posted by bmacfrs

Was that with coilovers set to relatively even ride heights? Why was yours so close already?

I did what it think most do when installing the coilovers. I set the heights so the car was about an inch lower, even from left to right, and slightly lower in rear. Measured from fender edges to hub center and pinch welds to ground. When I put it on the scales, with my weight and fuel, the numbers were all over the place. the cross was 45%.

Now, i'm a 3/4 inch difference from my lowest fender measurement to the tallest. Seems like a lot of variance to me.

Yes, the heights are even in the front, as measured by the threads on the shock bodies. The RR is 2 mm lower than the LR, again as measured by the threads. I tried to get a 0 rake as measured at the sill by the pinch welds.


I'm not sure what the variance in height at the fenders is, but it's not zero. But I've never had a change to measure the fender heights on a completely flat surface -- my garage floor is uneven.


Are you sure that each of your scale pads was level with the others? Did you have slip plates on top of the scales? There could also be some binding in your suspension, but I'd be surprised if endlink preload could cause a 5% difference in cross weight.

[CoolHandMoss]

What rear endlinks allow for quick and easy adjustments? I have used the Perrin endlinks and they seized to the point of being irreparable. I am using the whiteline endlinks now and they are terribly difficult to get installed into any hole but the center hole. Are there any with a good range of motion that allows quick and easy adjustments?

[strat61caster]

I like my Racer X rear end links, cheap too compared to everyone else. You have to unbolt to adjust length but they're compact as a result.

+1 on the corner balance woes, this car seems unresponsive to my ride height changes affecting corner weights, sway bars unhooked, ride heights are pretty close to nice based on fender measurements and measuring the pinch welds to the 'floor' (I use a laser level with the car on level platforms) jack three turns into the corners and next to nothing happens. Any tips would be appreciated, I think I need to take a apart the suspension and just try to rezero the heights and preload, good opportunity to check the top hats and clean it though.

[ka-t_240]

Originally Posted by CoolHandMoss

What rear endlinks allow for quick and easy adjustments? I have used the Perrin endlinks and they seized to the point of being irreparable. I am using the whiteline endlinks now and they are terribly difficult to get installed into any hole but the center hole. Are there any with a good range of motion that allows quick and easy adjustments?

You will probably end up breaking them, so id suggest upgrading sooner than later.

I have Hotchkiss bars front and rear, they came with endlinks

[CoolHandMoss]

Originally Posted by ka-t_240

You will probably end up breaking them, so id suggest upgrading sooner than later.

I have Hotchkiss bars front and rear, they came with endlinks

So the Whiteline endlinks won't even work with the Whiteline sway bar without breaking? Is this a thing? I thought they were designed to work together since they are sold together. They are definitely inconvenient and far from ideal but I have never heard of them breaking.

[M0nk3y]

Originally Posted by CoolHandMoss

So the Whiteline endlinks won't even work with the Whiteline sway bar without breaking? Is this a thing? I thought they were designed to work together since they are sold together. They are definitely inconvenient and far from ideal but I have never heard of them breaking.

Whiteline just in general doesn't make the best of stuff really.

I run RacerX rear endlinks.

[ka-t_240]

Originally Posted by CoolHandMoss

So the Whiteline endlinks won't even work with the Whiteline sway bar without breaking? Is this a thing? I thought they were designed to work together since they are sold together. They are definitely inconvenient and far from ideal but I have never heard of them breaking.

I don't have a whiteline rear bar, but I broke 3 or 4 of their rear endlinks before going to something else. My friend with a sti has broke 2(with whiteline bar). Have seen numerous posts about broken whiteline rear endlinks. They are just very weak.

I ended up selling all my sway bar and end-link stuff, then upgraded to Hotchkis stuff. Couldn't be happier.

[H1C]

Originally Posted by strat61caster

+1 on the corner balance woes, this car seems unresponsive to my ride height changes affecting corner weights, sway bars unhooked, ride heights are pretty close to nice based on fender measurements and measuring the pinch welds to the 'floor' (I use a laser level with the car on level platforms) jack three turns into the corners and next to nothing happens. Any tips would be appreciated, I think I need to take a apart the suspension and just try to rezero the heights and preload, good opportunity to check the top hats and clean it though.

Do you have some way of making sure that the suspension settles and unbinds on the scale pads?:



https://robrobinette.com/corner_weight.htm

Once you get the car up on the scales you'll need to roll the car back and forth a few inches several times, being careful not to push it off the scales, to unbind the suspension (as the car is lowered onto the scales the tires will need to spread out to unbind the suspension). You will have to repeat this every time you lower the car onto the scales. You can also put two linoleum tiles with salt between them on your scales. The salt acts as tiny ball bearings and will allow the tires to spread when the car is lowered onto the scales.