fc rear roll center
02-25-14, 02:21 PM
#28
Travis, I think you mean if you lower the front roll center you will increase steering.
Fixing the height of the lower ball joint is actually easy, but it does require fabrication. I was thinking of removing the stock holder and switching it to the top of the control arm thus changing the angle of the control arm to result a better camber curve in compression.
Fixing the height of the lower ball joint is actually easy, but it does require fabrication. I was thinking of removing the stock holder and switching it to the top of the control arm thus changing the angle of the control arm to result a better camber curve in compression.
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02-26-14, 11:32 AM
#29
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You could also try raising the inboard mounting points of the front lower control arm. But the frame/chassis is in the way.
by a little, is like 1/2"
02-26-14, 11:38 AM
#30
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Travis, I think you mean if you lower the front roll center you will increase steering.
Fixing the height of the lower ball joint is actually easy, but it does require fabrication. I was thinking of removing the stock holder and switching it to the top of the control arm thus changing the angle of the control arm to result a better camber curve in compression.
Fixing the height of the lower ball joint is actually easy, but it does require fabrication. I was thinking of removing the stock holder and switching it to the top of the control arm thus changing the angle of the control arm to result a better camber curve in compression.
02-26-14, 02:32 PM
#31
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Does not change the roll center, but does add camber on compression which is normally foreign to a Macstrut car.
I was thinking of making lower ball joint brackets using a 1/2" spherical bearing...that way you could move the spindle relative to the ball joint vertically.
I was thinking of making lower ball joint brackets using a 1/2" spherical bearing...that way you could move the spindle relative to the ball joint vertically.
02-26-14, 03:44 PM
#32
Does not change the roll center, but does add camber on compression which is normally foreign to a Macstrut car.
I was thinking of making lower ball joint brackets using a 1/2" spherical bearing...that way you could move the spindle relative to the ball joint vertically.
I was thinking of making lower ball joint brackets using a 1/2" spherical bearing...that way you could move the spindle relative to the ball joint vertically.
an easy way to add more camber gain is to increase the SAI (ie, camber plates)
also a 1/2" spherical bearing seems awfully small for a ball joint..
02-27-14, 11:26 AM
#33
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Eage8...looking at 1/2" spherical bearings...radial load in excess of 25000 lb. Could go up to the 5/8" for 44600 lb rating. I would think that would be enough for my 2700# race car! By using the spherical, you can add shims between the LCA and spindle to change RC.
02-27-14, 11:31 AM
#34
Eage8...looking at 1/2" spherical bearings...radial load in excess of 25000 lb. Could go up to the 5/8" for 44600 lb rating. I would think that would be enough for my 2700# race car! By using the spherical, you can add shims between the LCA and spindle to change RC.
and how do you plan on connecting that bolt to the spindle?
02-27-14, 02:53 PM
#37
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Haven't had it apart so I did not know that. In that case, I would machine an 18mm stud on top to accept the 5/8" bearing on the bottom, with a lock nut.
02-28-14, 11:01 AM
#38
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material is super important.
TBD on using a larger bearing, and bigger bolt
02-28-14, 11:16 AM
#39
+1 i just drew a bolt up in solidworks. its 18mm, like stock, and as you would expect, the longer the bolt the weaker it gets, so spherical bearing + bolt solution has a limit to how long you can make it before the wheel falls off in a turn
material is super important.
TBD on using a larger bearing, and bigger bolt
material is super important.
TBD on using a larger bearing, and bigger bolt
even though the pinch bolt area is 18mm. the recess where the pinch bolt goes through goes down to 15mm which is where mine broke.
02-28-14, 11:43 AM
#40
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with the strength testing i'm not 100% sure i'm using the right numbers, if you have a 2800# car with 50/50 weight distribution, 1600# but add 1g, and i'm just testing #2800lbs.
i'm not sure if that's too much, or not enough...
and of course there is the oddity that if i have the computer add a stress diagonally, vs straight it makes a difference, how that is possible on something round, i do not understand
i'm not sure if that's too much, or not enough...
and of course there is the oddity that if i have the computer add a stress diagonally, vs straight it makes a difference, how that is possible on something round, i do not understand
02-28-14, 01:40 PM
#41
with the strength testing i'm not 100% sure i'm using the right numbers, if you have a 2800# car with 50/50 weight distribution, 1600# but add 1g, and i'm just testing #2800lbs.
i'm not sure if that's too much, or not enough...
and of course there is the oddity that if i have the computer add a stress diagonally, vs straight it makes a difference, how that is possible on something round, i do not understand
i'm not sure if that's too much, or not enough...
and of course there is the oddity that if i have the computer add a stress diagonally, vs straight it makes a difference, how that is possible on something round, i do not understand
HOW TO: Ultimate budget front LCAs - Nissan Road Racing Forums
Originally Posted by Def from NRR
As far as if a bolt is strong enough, every analysis I did, even REALLY worst case scenarios led me to believe a 3/4" Grade 8 bolt is grossly overkill for anything you'd see on the car. I imagine you'll rip the whole front quarter of the unibody apart before you start coming close to breaking that bolt. When you get it in your hand I think you'll understand just how big a 3/4" bolt is. For an idea of the strength of a 3/4" Grade 8 bolt, even with a single shear condition with 2" of spacing, simple analysis suggested that just ONE bolt could suspend MULTIPLE S13's.
02-28-14, 09:10 PM
#43
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Some guys over at nissanroadracing did something similar with the same size bolt:
HOW TO: Ultimate budget front LCAs - Nissan Road Racing Forums
HOW TO: Ultimate budget front LCAs - Nissan Road Racing Forums
http://nucor-fastener.com/Files/PDFs...r_Strength.pdf
03-03-14, 11:23 AM
#46
I'm thinking why not drill out 18mm to 19mm or 3/4" and using a huge bolt.
I did not measure the stock thickness of the metal on the ball joint, but I was thinking 3/8" would be ok? I guess the hardest part would be machinging the bore for the bearing.
03-03-14, 11:36 AM
#47
I just need to see how my wheel fitment is with 17x9 +22 on the shine fenders.
I'm thinking why not drill out 18mm to 19mm or 3/4" and using a huge bolt.
I did not measure the stock thickness of the metal on the ball joint, but I was thinking 3/8" would be ok? I guess the hardest part would be machinging the bore for the bearing.
I'm thinking why not drill out 18mm to 19mm or 3/4" and using a huge bolt.
I did not measure the stock thickness of the metal on the ball joint, but I was thinking 3/8" would be ok? I guess the hardest part would be machinging the bore for the bearing.
https://www.rx7club.com/race-car-tec...cones-1058123/
the stock ball joint is aluminum, so the thickness could be smaller if you make a steel ball joint.
I don't know how thick my AWR ball joint is, but I'd probably say somewhere around 1/4" steel
04-18-14, 05:50 PM
#48
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I also wanted to raise the rear for more anti-squat. Ultimately, 1/2" just isn't enough to justify the effort. The frame needs to move at least 2" up to help with the lowered stance and give the increased anti-squat I'm looking for. I've thought about cutting it all apart and just welding brackets to the frame / roll cage to locate the outer control arm mounts and keeping a cut down center section of the subframe to support the camber links, and diff front.
I've also looked at the front roll issue and tried getting the setup from AWR. I'll have to give him a call as e-mail doesn't appear to get his attention (everyone has their best way to contact them).
-Trent
I've also looked at the front roll issue and tried getting the setup from AWR. I'll have to give him a call as e-mail doesn't appear to get his attention (everyone has their best way to contact them).
-Trent
04-18-14, 09:37 PM
#49
I also wanted to raise the rear for more anti-squat. Ultimately, 1/2" just isn't enough to justify the effort. The frame needs to move at least 2" up to help with the lowered stance and give the increased anti-squat I'm looking for. I've thought about cutting it all apart and just welding brackets to the frame / roll cage to locate the outer control arm mounts and keeping a cut down center section of the subframe to support the camber links, and diff front.
I've also looked at the front roll issue and tried getting the setup from AWR. I'll have to give him a call as e-mail doesn't appear to get his attention (everyone has their best way to contact them).
-Trent
I've also looked at the front roll issue and tried getting the setup from AWR. I'll have to give him a call as e-mail doesn't appear to get his attention (everyone has their best way to contact them).
-Trent
I have the idea of making my own front roll center, but I am too lazy to buy the bearing to figure the size I would need to get machined so I could fit a snap ring, then source a bolt and spacers. I really should right now since I am waiting on my fenders.
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