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GT350/S550 Vertical Links

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Just curious if anyone has installed aftermarket vertical links? If so did you notice any improvement in wheel hop and more importantly turn-in on track? I'm not having wheel hop issues but remember replacing the LCA's on my Boss cured the wheel hop and improved the feel of the rear end on corner entry.

https://www.bmrsuspension.com/?page=products&productid=1572&superpro=0

Screen Shot 2017-07-17 at 7.14.14 PM.png

Also a couple of videos from FTBR showing the flex in the rear of a S550


 
Never experienced wheel hop but the Steeda vertical links was one of the first things I did. My combination that I am running now is as follows:

R springs and rear sway bar
Steeda vertical links
Steeda IRS brace
Steeda diff lockout bushings (red)
Steeda adj camber links
FTBR adj sway bar end links

No increase in NVH and entry/exit is very predictable. Refrained from adj. toe links and spherical bushings on account of the NVH increase. The IRS brace did wonders really. The forward/rearward movement of the IRS under load is gone. BMR approaches it differently with their cradle bushing lockout kits.
 
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I had pretty in depth correspondence with James at FTBR about stability of the IRS. He initially tried to sell me the whole kit they offer for the IRS. I tried to pin him down and asked specifically what was most necessary to address the IRS weakness in an open track setting, as observed in the videos posted above. Vertical links ended up not being mentioned in that equation. Instead the emphasis was the subframe, lca, and uca bushings/bearings. I was told the nvh increase would be neglible. I was also told the diff bushings are biggest NVH culprit.

After some more research I decided to take the plunge with what James recommended. The bushing/bearing upgrade really stiffened the rear. No increase in N or V, but many would subjectively say there was an increase in H. It took a couple of track days to really break everything in. Much of the initial rigidity I felt was stiction in the new stuff that just needed to be worked out. The H is now much more subtle than it was post install.

I took this leap because I noticed a bit of a wiggle in the rear under heavy load....most often when tracking out of a very fast turn. On track the rear performs awesome and without a hint of wiggle. It is all but forgotten so the focus can be on pushing harder!

Overall, not an answer to the initial question, but the route I ended up taking to address the topic in question.
 
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http://fulltiltboogieracing.com/2016_GT350_and_GT350R_Suspension_Parts_and_Tools.htm

I went with the following part numbers: FT522; FT548; FT540; FT530. After seeing how flimzy the front end links are, I also went with FT560.

I'd send them an email inquiry and ask away. I asked a lot of questions and got prompt detailed responses. I don't know if this mod made me faster, but I do know my car feels very dialed in and confidence inspiring. I also know my car is really fast. As dialed in as the car feels, I think stiffening up the front a bit more will make it even better. I'm pretty sure I'll do the FP springs and sway bars. After that i can't see me doing much else to the car.

I went with FTBR because I like the quality of their stuff, and they were the most candid and detailed when I started inquiring. They definitely seemed more knowledgeable about the effects of open tracking on the IRS, whereas others couldn't get past a wheel hop discussion.
 
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Our recipe that seems to have worked for several Customers is Delrin Cradle Bushings, knuckle bearing, lower rear control arm bearing. We do not speak wheel hop, so braces are a waste of time and money. Solve the problem buy eliminating the deflection. The stock vertical links are fine and sometimes its better to let things have some 'freedom' If it is a track only car you can do the aluminum cradle bushings but honestly the delrin locate the cradle. If you feel the need you can change the differential bushings but that does not influence handling in an IRS, possibly wasted motion through the axles. Again some deflection helps parts not break. Poly/Delrin/Aluminum would all be effective but not a must. Material choice is subjective based on NVH tolerance and true purpose of the vehicle.
 
I had pretty in depth correspondence with James at FTBR about stability of the IRS. He initially tried to sell me the whole kit they offer for the IRS. I tried to pin him down and asked specifically what was most necessary to address the IRS weakness in an open track setting, as observed in the videos posted above. Vertical links ended up not being mentioned in that equation. Instead the emphasis was the subframe, lca, and uca bushings/bearings. I was told the nvh increase would be neglible. I was also told the diff bushings are biggest NVH culprit.

After some more research I decided to take the plunge with what James recommended. The bushing/bearing upgrade really stiffened the rear. No increase in N or V, but many would subjectively say there was an increase in H. It took a couple of track days to really break everything in. Much of the initial rigidity I felt was stiction in the new stuff that just needed to be worked out. The H is now much more subtle than it was post install.

I took this leap because I noticed a bit of a wiggle in the rear under heavy load....most often when tracking out of a very fast turn. On track the rear performs awesome and without a hint of wiggle. It is all but forgotten so the focus can be on pushing harder!

Overall, not an answer to the initial question, but the route I ended up taking to address the topic in question.

http://fulltiltboogieracing.com/2016_GT350_and_GT350R_Suspension_Parts_and_Tools.htm

I went with the following part numbers: FT522; FT548; FT540; FT530. After seeing how flimzy the front end links are, I also went with FT560.

I'd send them an email inquiry and ask away. I asked a lot of questions and got prompt detailed responses. I don't know if this mod made me faster, but I do know my car feels very dialed in and confidence inspiring. I also know my car is really fast. As dialed in as the car feels, I think stiffening up the front a bit more will make it even better. I'm pretty sure I'll do the FP springs and sway bars. After that i can't see me doing much else to the car.

I went with FTBR because I like the quality of their stuff, and they were the most candid and detailed when I started inquiring. They definitely seemed more knowledgeable about the effects of open tracking on the IRS, whereas others couldn't get past a wheel hop discussion.

Thanks for posting your experience. I've been thinking about doing this for the same reasons as you. I'm relieved to hear the NVH wasn't increased too much.

Did you do the removal/install of the bushings yourself?
If so, how did it go? Any tips?
 
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I did not.....it's pretty involved and not my area of expertise unfortunately. I am fortunate to have a great shop local and my tech is a good friend who is experienced in racing and building racecars. He took care of it and did spent about 8 hours on it if I recall correctly. I do know that FTBR can give you a good idea of install time for what you intend to do and will also help with tech support.
 

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