Suspension upgrades

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May 1, 2012 | 07:38 PM
  #16  
Quote: Got it -- non-centered hole towards the rear. I assume that's the same for Front and rear?

Thanks again!
Henry
As much as I value Mr. White's opinion I have to respectfully disagree with him on this one. If you are using the GT3 LCA on the front of the car then the off center hole must point towards the FRONT of the car if you wish for your caster to remain essentially unchanged. I say this from direct experience installing these things on my car and pulling my hair out over it. You are certainly free to install these things as you wish but I've been there and just trying to save you some headaches since clearance issues are a huge concern between the front tire and the front fender liner on the 996tt with aggressive wheel fitments as you probably already know. Having the correct caster is paramount. Take a look at the attached picture of the right GT3 LCA mounted on the left front of my car. The off center hole is pointed toward the front of the car. Now, sit back, crack a beer and think about the geometry at play here. As you add shims to the GT3 LCA you are effectively making it longer. Now, as you make it longer, the lower diagonal control arm (which is a fixed length) will naturally pull the GT3 LCA (and the whole wheel assembly) forward in the wheel well. As a result, you NEED to make sure the diagonal lower control arm is mounted into the off center hole pointing toward the front of the car which will effectively push the GT3 LCA (and the whole wheel assembly) back to the original caster position. If you were to have the off center hole toward the back of the car your whole wheel assembly would be pulled too far forward and you would likely have clearance issues. I did. As a point of reference, with 7mm of shims added to the GT3 LCA and mounting them as described here, my caster remained unchanged from where it was with the fixed LCA. Hope this helps....

 

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May 1, 2012 | 07:48 PM
  #17  
I understood his instructions as the offset hole needs to be closest to thrust arm itself. That makes sense to counter the additional length of the LCA by adding shims.

Sorry if I'm just making this more confusing haha
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May 1, 2012 | 07:54 PM
  #18  
Quote: As much as I value Mr. White's opinion I have to respectfully disagree with him on this one. If you are using the GT3 LCA on the front of the car then the off center hole must point towards the FRONT of the car if you wish for your caster to remain essentially unchanged. I say this from direct experience installing these things on my car and pulling my hair out over it. You are certainly free to install these things as you wish but I've been there and just trying to save you some headaches since clearance issues are a huge concern between the front tire and the front fender liner on the 996tt with aggressive wheel fitments as you probably already know. Having the correct caster is paramount. Take a look at the attached picture of the right GT3 LCA mounted on the left front of my car. The off center hole is pointed toward the front of the car. Now, sit back, crack a beer and think about the geometry at play here. As you add shims to the GT3 LCA you are effectively making it longer. Now, as you make it longer, the lower diagonal control arm (which is a fixed length) will naturally pull the GT3 LCA (and the whole wheel assembly) forward in the wheel well. As a result, you NEED to make sure the diagonal lower control arm is mounted into the off center hole pointing toward the front of the car which will effectively push the GT3 LCA (and the whole wheel assembly) back to the original caster position. If you were to have the off center hole toward the back of the car your whole wheel assembly would be pulled too far forward and you would likely have clearance issues. I did. As a point of reference, with 7mm of shims added to the GT3 LCA and mounting them as described here, my caster remained unchanged from where it was with the fixed LCA. Hope this helps....
You are correct and in my last post gave the advise that the off-center hole always needs to be facing towards where the thrust / diagonal arm comes from. Will edit the post you quoted in order to not confuse future readers, the diagonal arms come from the front on all corners - total brainfade on my part.
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May 1, 2012 | 07:55 PM
  #19  
Quote: I understood his instructions as the offset hole needs to be closest to thrust arm itself. That makes sense to counter the additional length of the LCA by adding shims.

Sorry if I'm just making this more confusing haha
Those are the instructions, I just made a brainfade re the front diagonal arms, they also anchor from the front, not from the rear. Since they anchor from the front the non-centered holes must face fwd. See the photo how the off-center hole is used facing towards the thrust/diagnoal arm. Sorry about the confusion.
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May 1, 2012 | 08:04 PM
  #20  
Quote: Those are the instructions, I just made a brainfade re the front diagonal arms, they also anchor from the front, not from the rear. Since they anchor from the front the non-centered holes must face fwd. See the photo how the off-center hole is used facing towards the thrust/diagnoal arm. Sorry about the confusion.
The interesting thing is that in order to do it this way you have to flip the arms and mount them backwards, the left one on the right side of the car and vice versa. The factory maintenance manual has it wrong with the instruction to mount the off center hole towards the rear but it has to be a typo. It wouldn't be the first I've come across.
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May 6, 2012 | 09:38 AM
  #21  
Sure enough. Had them backwards, flipped PSM bracket thing to opposite side and now it all makes sense for the thrust arm/offset hole.

Thanks again for the heads up.
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May 6, 2012 | 10:48 AM
  #22  
As much as I like this info this thread was not about your guys debate on which way to install your control arm thrust bushings.

But did any of you change out your stock pivot bushing for a monoball bushing on the stock control arm.

If so how much harshness if any did it add to your ride or noise in the cab??? I do not know if I am going overboard and it will get to noisey in the cab. I am sure my ohlins shocks will be way more compliant than stock but how loud will all these rod ends make it I will find out.

So monoballs --> Y or N
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