heavy85 Posted October 24, 2015 Share Posted October 24, 2015 (edited) Finally converting the TC rod to rod ends. Have run the Gman aluminum cup / nylon ball w/rubber bushing on the back side set-up for a long time. Something that becomes immediately noticed is that by adding a bracket to hold the rod end on the frame side you effectively shorten the TC rod. Since rules are open, Im free to remocate the mount location. Has anyone mapped the suspension and determined a) the impact of a shorter TC rod and b.) if you could move the frame mount where is a good target location? Edited October 24, 2015 by heavy85 Quote Link to comment Share on other sites More sharing options...
Jay Gadsby Posted October 24, 2015 Share Posted October 24, 2015 No info for you, but interested since I am about to replace my front frame rails. Would be primo timing to do this sort of job. Good luck! Quote Link to comment Share on other sites More sharing options...
JMortensen Posted October 24, 2015 Share Posted October 24, 2015 I worked through this stuff years ago and came to the conclusion that the pivot should be in line with the LCA pivot. I slotted the box that I attached the rod to and after putting it on the ground I found that my highest setting is basically level. If the rod points down at the front you get anti dive, up is pro dive. Always interesting to see what you do. http://forums.hybridz.org/topic/41611-tc-rod-pivot-relocation-bad-dog-subframe-connectors-slotted-crossmember/ Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted October 24, 2015 Share Posted October 24, 2015 Also interested, but no info to contribute. I'm curious to see if the stock TC rod mount could be used as a radius rod mount for a solid dropped front axle for a drag/landspeed car where I don't want camber changes or toe changes as the ride height changes. Quote Link to comment Share on other sites More sharing options...
heavy85 Posted October 25, 2015 Author Share Posted October 25, 2015 Quickly realizing its going to be a PITA to locate accurately relative to the LCA mount. Quote Link to comment Share on other sites More sharing options...
johnc Posted October 25, 2015 Share Posted October 25, 2015 Think of the LCA and the TC Rod as two sides of a right triangle with the 90 angle between the LCA and the TC Rod mount. If you move the TC Rod mount in or out you affect caster and the camber curve. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted October 25, 2015 Share Posted October 25, 2015 Not sure what the PITA is, I don't remember it being that bad. Just measured from the inside of the frame rail to the center of the bolt, then figured the center of a rod end in my new piece of frame, measured the same way. Quote Link to comment Share on other sites More sharing options...
tube80z Posted October 25, 2015 Share Posted October 25, 2015 You could move it to mount on your k-member. That would be slightly forward of the TC mount but allow it to align. That said a long time ago a friend measured all this and used wingeo to see the curves. While it did change it wasn't some major issue. When you pushed the front wheels forward for more caster the curves were very close again. If you want to do the measurements I'll put it in susprog and then we can share the plots so you can decide. Quote Link to comment Share on other sites More sharing options...
heavy85 Posted November 1, 2015 Author Share Posted November 1, 2015 You could move it to mount on your k-member. That would be slightly forward of the TC mount but allow it to align. That said a long time ago a friend measured all this and used wingeo to see the curves. While it did change it wasn't some major issue. When you pushed the front wheels forward for more caster the curves were very close again. If you want to do the measurements I'll put it in susprog and then we can share the plots so you can decide. Cary I'll bite. Measurements are close but may be off 1/16" here or there. - Stock arms 11.5" from pivot to ball joint - Ball joints 3/8" forward of the lca pivot - TC pivot 7/16" outboard of lca pivot - TC pivot 5/16" lower than lca pivot - 14 3/16" between TC pivot and lca pivot - 240 struts sectioned 2" - If I just add a bolt in rod end the TC rod would shorten about 1 1/4" I'm thinking as already mentioned to put the lca and TC mount in line. It's got a bit of pro dive in now but don't really have a clue where to go vertically. Can put it just about anywhere that would get the best performance. I'm also thinking of pushing the upper strut mount forward 1" and lengthen the TC rod accordingly to lengthen the wheelbase - should move 0.5% weight towards the rear and I want as much as possible. Quote Link to comment Share on other sites More sharing options...
tube80z Posted November 1, 2015 Share Posted November 1, 2015 Cary I'll bite. Measurements are close but may be off 1/16" here or there. - Stock arms 11.5" from pivot to ball joint - Ball joints 3/8" forward of the lca pivot - TC pivot 7/16" outboard of lca pivot - TC pivot 5/16" lower than lca pivot - 14 3/16" between TC pivot and lca pivot - 240 struts sectioned 2" - If I just add a bolt in rod end the TC rod would shorten about 1 1/4" I'm thinking as already mentioned to put the lca and TC mount in line. It's got a bit of pro dive in now but don't really have a clue where to go vertically. Can put it just about anywhere that would get the best performance. I'm also thinking of pushing the upper strut mount forward 1" and lengthen the TC rod accordingly to lengthen the wheelbase - should move 0.5% weight towards the rear and I want as much as possible. What is the ride height? I also need to know the top strut location (where the mono ball is). I can fudge a lot of this if you want but ride height will be important. And to set expectations it may take a few weeks to get this for you as my wife is recovering from surgery. Susprog just gives you numbers and those will need to be plotted in excel. I'll overlay the two options so you can see if this is important. Cary Quote Link to comment Share on other sites More sharing options...
We Bad Posted November 1, 2015 Share Posted November 1, 2015 If you aren't constrained by the rules why not move it to in front of the LCA to put the rod in tension? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 1, 2015 Share Posted November 1, 2015 Then you have sway, steering, and TC rod in the same space. If you were changing up the steering a rear steer setup would allow for lots more ackerman. Some of the aftermarket units that use a inner tie rod end rather than a rod end don't change the length as much, so that would minimize any potential negative effect. Quote Link to comment Share on other sites More sharing options...
heavy85 Posted November 3, 2015 Author Share Posted November 3, 2015 (edited) Edit: sorry to hear about your wife. Hope recovery goes well! The LCA point front the center down towards the tire by ~3 deg if that helps with ride height? Will have to take the strut off to measure but the strut top us currently about 1/2" rear and 1/2 inboard of stock location. Also have 3/4" spacers between struts and steering arm. Edited November 3, 2015 by heavy85 Quote Link to comment Share on other sites More sharing options...
heavy85 Posted November 3, 2015 Author Share Posted November 3, 2015 If you aren't constrained by the rules why not move it to in front of the LCA to put the rod in tension? Why? Quote Link to comment Share on other sites More sharing options...
tube80z Posted November 4, 2015 Share Posted November 4, 2015 Edit: sorry to hear about your wife. Hope recovery goes well! The LCA point front the center down towards the tire by ~3 deg if that helps with ride height? Will have to take the strut off to measure but the strut top us currently about 1/2" rear and 1/2 inboard of stock location. Also have 3/4" spacers between struts and steering arm. If you have the ground to bottom of the crossmember I can figure the rest out. I have measurements for the chassis assuming the strut towers haven't been moved. Thanks for the best wishes. She's doing fine but still has a lot of pain. Cary Quote Link to comment Share on other sites More sharing options...
tube80z Posted November 4, 2015 Share Posted November 4, 2015 If you aren't constrained by the rules why not move it to in front of the LCA to put the rod in tension? That seems like an easy solution until you actually start looking at doing it. Now you need to add more chassis in front of the car, change to rear steer, deal with rack/oil pan interference. So while it makes one thing much easier you then have many more things to fix. And in the end you adding mass in front of the wheel base rather than moving it backwards. While a small amount it all this adds up. Quote Link to comment Share on other sites More sharing options...
heavy85 Posted November 5, 2015 Author Share Posted November 5, 2015 Thats a problem. Car is currently dissasembled on jackstands for the winter work. The lca pivot is about 1/4 higher than stock and points down ~3 deg. R comps are ~23" diameter and 200 'street' tires (race on both for different events) are 25" diameter although Im contemplating buying another set of 17" wheels and going up to the ~25" R comps. Quote Link to comment Share on other sites More sharing options...
tube80z Posted November 6, 2015 Share Posted November 6, 2015 I'm going to guess 4 inches then. I can try lower or higher to see how that goes. Actually, I'm going to move a number of things around so everyone can see effects of moving pickup points. Cary Quote Link to comment Share on other sites More sharing options...
heavy85 Posted November 7, 2015 Author Share Posted November 7, 2015 That would be great Cary. Im to the point that rules are typically unlimited for suspension so will move things around to get the best performance. Look forward to your results. Quote Link to comment Share on other sites More sharing options...
heavy85 Posted December 1, 2015 Author Share Posted December 1, 2015 (edited) Well this is what I came up with. Its overbuilt but I accept that. Can move the shims around to adjust things. It will fit either horizontally so I can shim it inboard to bring back closer in line with the LCA pivot, or can be mounted vertical so I can play with anti-dive. Its got some pro-dive if centered and from some reading doesnt sounds like really want anti-dive with struts as it tends to bind them up. Not sure how to set it yet but at least its bolt in and adjustable so can always easily change the settings. Cameron Edited December 1, 2015 by heavy85 Quote Link to comment Share on other sites More sharing options...
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