Fuck turning wrenches, I wanna go wheeling; So I sold the taco.

Arcticelf

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Turns out the jokes on me.

Can anyone explain why that sketch has no applicability to the toyota IFS?

Hint: Theta(U) and Theta(L) are the UCA and LCA angles, respectively.
 

madtaco461

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I can't really follow the drawing that well. Looks like you are missing the spindle, 4 bar linkage design.
 

Arcticelf

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I can't really follow the drawing that well. Looks like you are missing the spindle, 4 bar linkage design.

Close, this was an attempt at calculating the instant center for an arbitrary suspension position.

Unfortunately, the configuration in the sketch is not physically possible for the Toyota IFS.

Also unfortunately I spent 4 hours factoring and expanding polynomials before I realized that.
 

madtaco461

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Close, this was an attempt at calculating the instant center for an arbitrary suspension position.

Unfortunately, the configuration in the sketch is not physically possible for the Toyota IFS.

Also unfortunately I spent 4 hours factoring and expanding polynomials before I realized that.

is it because of the anti dive in the uca why it can’t happen?

Or because the ic goes from the outside the car to the inside? If this reason couldn’t you put some limits at infinity?
 

Arcticelf

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is it because of the anti dive in the uca why it can’t happen?

Or because the ic goes from the outside the car to the inside? If this reason couldn’t you put some limits at infinity?

The relative lengths of the control arms forces the angles such that the IC will be either outside of the vehicle, or below line A in that diagram. So E=T-B, not E=B+T, as shown in that picture.
 

Arcticelf

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Cycled the prototype LCA.

Need to increase the mid arm bend to 30 degrees to allow more clearance for the inner CV.

This should also provide additional angle on the outer uniball cup to allow full droop travel.
 

Arcticelf

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Ordered new hub plates, I guess I'm committed to building spindles now.

The real question is: A arm or J Arm style UCAs? The latter have to have stronger mounts, since it's tension only, however more room for coilovers and potentially bypasses later.
 

Stairgod

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J arm could be interesting. And you have all kinds of room for the mounts since no inner fenders and engine cage.
 

AssBurns

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Ordered new hub plates, I guess I'm committed to building spindles now.

The real question is: A arm or J Arm style UCAs? The latter have to have stronger mounts, since it's tension only, however more room for coilovers and potentially bypasses later.
New hub plates? Where did you get those from?

Do J arms get in the way of steering at all? Seems like it could at bump and full lock.
 

Arcticelf

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New hub plates? Where did you get those from?

Do J arms get in the way of steering at all? Seems like it could at bump and full lock.

https://zonamotorsports.com/shop

They don't have them for sale on the website, but Bobby has them in-stock.

Stearing clearance will be an issue for the J-Arm, at full lock, but it shouldn't be that hard to clear both the shock and the tire. I'll make the spindle shorter too, so I can stuff the upper pivot inside the wheel diameter. I'll loose camber gain on cornering, but that should be okay.
 

Arcticelf

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Today's adventure in geometry hell:

Draw the OEM spindle and control arms in CAD. Then locate the instant centers.

Then use trial and error to find a combination of spindle height, LCA mounting points, and LCA length which will result in similar instant centers when combined with a +1.5" long LCA.

It can be done, and I think somewhat easier with a J arm. That should let me take the UCA crashing into the shock completely out of the picture, which means I can get 12 to 16" of travel, limited by the CV angles.
 
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