Apex1.0

I figured it out. I spent about 4 hours playing with a long acre bumpsteer gauge and Megan toe links. I have tons of data overall, here are the major points.

Bases on ride height of 13.4" hub to body. I used a travel sweep of 3.5" total, 2" bump and 1.5" extension.
At that ride height the factory setup has about .090" of bump steer total.
The toe in at 2" of bump is about .040". The toe out at 1.5" of extension is about .050". For comparison toe in at 1.5" of bump is .025".

So to your point the negative toe on extension is more extreme than the toe in.

With the bumpsteer kit, I tried the large bushing first, and it reversed the toe curve; toe out on bump, toe in on rebound. Total toe change around .080" I switched to the small bushing and things tightened up quite a bit. I was down to a total toe change of around .015" but it was toeing out on bump. I spent some time playing with the toe link eccentric, because it does slightly affect the toe curve. Here is where I think I am going to end up:

Rebound
1.5" -.009" toe
1.0" -.003" toe
0.0". .000 toe
1.0" .001 toe
1.5" .005 toe
2.0" .010 toe
Compression

Total toe change is .019".

What do you think of that curve?

Slowcrash_101

That's much better! Dial in a bit more static toe in and you should be good to go. Remember you don't want to eliminate bump steer entirely, just constrain it. It should feel a lot better flying over bumps while cornering.

Apex1.0

Thanks!

So the right side is all dialed in now. The eccentric does have an effect on the toe curve because it actually moves the chassis mount point of the toe link. The difference in total bump steer was able to be changed about .025.

I measured the bump on the left side with the oem toe link. Interestingly it only has .053" of total bump steer, most of it is toe in on bump. Looking at the eccentric on the toe link, funny, it is in the exact same position I used on the right side after being optimized.

My theory is the left side is the best case senerio for bump steer because of the current eccentric adjustment.

I will work on this side later today.

Slowcrash_101

Where was the eccentric bolt positioned if you don't mind me asking? To make it simple you can just say quadrant 1,2,3,4 like quadrant 1 is 9-12 oclock 2 is 12-3 3 is 3-6.

Apex1.0

No problem. Left rear wheel of the car looking at it from behind. The bolt shaft/nut is in the 2:00 position. Or high right. This moves the pickup point inside and high on the chassis. I don't think most people can use this setting if they are trying to maximize camber. Or keep the positive toe from going too high.

Using the smaller bushing I could not get the left side to match the specs on the right side. I can make it so it have very little bumpsteer (.009" total), but the curve is backward. It toes out on compression a slight amount and in on extension. My thoughts are this is not a great curve. What do you think???

The fix is to take a little material off the smaller bushing to raise the toe link relative to the hub. This should bring it in the range where I can dial in the rest with the toe eccentric.

I am not sure how much to geek out over this. I am not sure hoe much of this will last after I bolt everything up and take it to get the static alignment done.

Slowcrash_101

Hmm maybe a compromise is in order

If the factory bump curve is .053" perhaps making the curve a little smaller with a focus on limiting toe out on extension would be the most practical direction.

Apex1.0

I took about .050" off the bushing. With that I was able to get this curve

-1.5" .000"
-1.0" .000"
0". .000"
1.0. +.003"
1.5. +.007"
2.0 +.009"

So I effectively have a little toe in on bump and no toe out on extension. I can either take more of the bushing to try and induce some toe out in rebound or I can try to adjust the other side to match this.

Slowcrash_101

That's probably ideal right there.

Apex1.0

That's kind of what I was thinking...

A little toe in on bump and zero on extension. I will just make sure I have enough static toe. Maybe around .032 degrees total.

Thanks for the input...

Apex1.0

For documentation sake...

Left Side

-1.5" .000"
-1.0" .000"
0" .000"
1.0". +.003"
1.5" +.007"
2.0" +.009"

Right side

-1.5" -.002"
-1.0" .000"
0" .000"
1.0" +.000"
1.5" +.002"
2.0" +.005"

For all intense purposes its zero bump steer on each wheel. I remeasured several times and there was consistency but this is the average. If I have the conversion right I plan on running about .065" of static positive toe in each wheel so it will always be within .010" of that figure through travel.

A few things I can say:

The AP1 toe curve is not too bad stock. However it is very easy to minimize. With the megan bump steer, the small busing is the one to use for 1" of lowering. Using The large bushing offered too much bump steer correction and reversed the toe curve. It starting bumping out on compression and in on rebound. Not good.

Once you have the best bushing you can use the OEM toe cam/eccentric bolt to fine tune the bumpsteer. Having the bolt head in the 12:00 position offers more bump steer correction (same as a larger bushing), and having it in the 6:00 position lessens the correction. Also, rotating the bolt head laterally (3:00 or 6:00) changed the way the correction affected the tor curve. It seemed moving the bolt head to the hub resulted in more abrupt bump correction. While moving the bolt head away from the hub resulted in more gradual bump correction.

Bottom line if you want to get it as close as possible you will need to play with it.