Forums/Z31P/z31-performance-upgrade-forums suspension-chassis-and-brakes/Soo how about thems swaybars?
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G-E: (2013-07-22 14:23:44)
A z31 front swaybar is ~38-1/2" at it's endlink mounts… here is a g35 one, it is ~37-5/8" at the same point…
The important difference is actually the location of those points away from the mounting bushings, almost 1-1/2" further, which would put it past the control arm by quite a bit if mounted in the same spot
But look how beefy they are stock…
NissanEgg: (2013-07-22 14:40:30)
Test fit to a Z31 and see where any issues would be. Especially that hump in the middle. Only downside to such a larger front bar is less oversteer. That would be good for the 2-seater guys that track their cars or lemons racers looking for more stability.
G-E: (2013-07-22 14:47:12)
If you mean the kickup for engine clearance, it is 2" deeper.... mounted normally, this would mean hanging a little lower, and a little forward
So in theory, you should only have additional clearance, I can't imagine it impacting the lower rad support
G-E: (2013-07-22 14:57:02)
What I was thinking is actually to flip it, so it intrudes into the engine bay, and move it forward an inch or so… the other good option if I want to keep the force centered on the lca, would be to use a subaru style C-shaped endlink, which would then attach to a bracket on the bottom of the lca
We'll see once I have a better idea how my control arm/tc rod combo is going to turn out
frostvectron: (2014-06-09 22:10:25)
Hey G-E, any update on this project? I am finding that I need a stiffer front swaybar. I'm currently running a 25mm addco (I think) bar. It needs to be bigger.
NissanEgg: (2014-06-09 23:56:18)
Nissan Motorsports sells a 28.5mm front bar. I run one in my Z.
G-E: (2014-06-10 00:47:30)
The update is… we need to clearance the tension rod bracket a touch, possibly a universal poly swaybar mount would work, may need custom, and there needs to be a custom endlink solution
For the endlink, the easiest would be welding a strap with a hole in it on the rear edge of the control arm with a 12mm hole in it (z33/g35 bar uses m12 endlinks not m10 like ours), the z33 endlink could then be used
frostvectron: (2014-06-10 01:44:36)
Nissan Motorsports sells a 28.5mm front bar. I run one in my Z.
Are they still available? How much are they and where can I purchase one? I flipped through the NISMO catalog and didn't see anything.
The update is… we need to clearance the tension rod bracket a touch, possibly a universal poly swaybar mount would work, may need custom, and there needs to be a custom endlink solution
For the endlink, the easiest would be welding a strap with a hole in it on the rear edge of the control arm with a 12mm hole in it (z33/g35 bar uses m12 endlinks not m10 like ours), the z33 endlink could then be used
Hmmmm. More fab work than I'd like to do, I think.
G-E: (2014-06-10 10:07:40)
It's not serious, but I have a lot of other things that need sorting out before I work on it, so for now it's a todo list item, nothing more [archived image: smile.png]
michaelp: (2014-06-10 15:07:03)
Hey G-E, any update on this project? I am finding that I need a stiffer front swaybar. I'm currently running a 25mm addco (I think) bar. It needs to be bigger.
I'd be hesitant to replace solid 1" bars with hollow bars that are 1.5" thick. The addcos are probably actually stiffer. Remember, larger dia. sway bar doesn't always mean stiffer.
Not sure about yours, but if my suspension were stiffer anywhere it'd be too stiff. Theres already virtually zero body roll. If you're trying to balance the car, try adjusting your coilover dampers. You can also adjust weight balance with different preloading and such. Or make the rear sway bar smaller if you're getting too much over steer.
frostvectron: (2014-06-10 16:42:32)
It's not serious, but I have a lot of other things that need sorting out before I work on it, so for now it's a todo list item, nothing more [archived image: smile.png]
Ah, has more to do with SCCA rules. Swaybars are unlimited but I can't change mounting points or modify the lca for swaybar attachment points.
I'd be hesitant to replace solid 1" bars with hollow bars that are 1.5" thick. The addcos are probably actually stiffer. Remember, larger dia. sway bar doesn't always mean stiffer.
Not sure about yours, but if my suspension were stiffer anywhere it'd be too stiff. Theres already virtually zero body roll. If you're trying to balance the car, try adjusting your coilover dampers. You can also adjust weight balance with different preloading and such. Or make the rear sway bar smaller if you're getting too much over steer.
On street tires the current suspension stiffness was perfect. On race rubber the front is rolling too much. I am lifting the inner rear tire on cornering. I need to go up in spring rates and get the stiffest front bar that I can find.
adamvann3: (2014-06-10 18:09:51)
Nissan Motorsports sells a 28.5mm front bar. I run one in my Z.
Lies, pg 19 http://www.nissanusa.com/nismo-web/N…talog-2012.pdf
Unless you have the in, then let me know
NissanEgg: (2014-06-10 21:35:35)
I will have to dig up the part number. Still have the box it came in. My Nissan employee discount was $98 shipped, but that was in 2011. Solid steel bar. Either made by ST or ADDCO. It's painted black out of the box. When I bought it there were still a dozen or so still in inventory.
G-E: (2014-06-10 22:08:40)
The g35 bar is 34mm and hollow…
Big Slappy Z: (2014-06-11 17:52:48)
What is the thickness of the hollow sway bar? Hollowing out a cylinder doesn't reduce the torsional stiffness by very much.
Assuming you have a 26mm diameter solid sway bar, a hollow 34mm diameter sway bar would only need a wall thickness of about 1.7mm to produce the same torsional stiffness. With that wall thickness and diameter you would keep the same torsional stiffness while reducing the weight of the bar (assuming they are the same approximate length) by about 67%.....
Of course if the walls are too thin, you have issues if they ever become loaded in bending, which they experience a bit of around the bushing mounting points.
G-E: (2014-06-11 18:49:10)
Well I can tell you that where the ends are squished together for the endlink mounts it's 10mm thick [archived image: smile.png]
Even accounting for powdercoat, that would make the wall thickness close to 4.5mm… what does your extrapolation tell you about that? [archived image: smile.png]
Big Slappy Z: (2014-06-11 19:02:40)
Well people were concerned that hollow sway bars would not be very stiff, and I disagree.
If you have 34mm sway bars with 4.5mm wall thickness, you would be approximately twice as stiff in torsion as a solid 26mm sway bar. Now of course this is assuming you have the same material (flexural modulus) and bar length…
adamvann3: (2014-06-11 20:56:00)
assuming you have the same material (flexural modulus) and bar length…
All of us without a text book call it modulus of elasticity [archived image: smile.png]
G-E: (2014-06-11 21:07:37)
From what investigation people have done, it appears the swaybar is 4130… I'm sure that's not the case for the original z31 swaybars, but that doesn't say anything about the nismo part
Big Slappy Z: (2014-06-11 21:20:56)
All of us without a text book call it modulus of elasticity [archived image: smile.png]
What I actually meant to say was shear modulus lol.
Although either way flexural modulus and elastic Elastic modulus are two totally different things
G-E: (2014-06-11 21:24:43)
Ok stop with the vocabulary pissing contest :P
frostvectron: (2014-06-12 02:33:11)
Ok some photos just emerged from the match tour this past weekend. This is why I need a bigger front bar (and stiffer springs). I thought I was just unloading the rear inner wheel, but it's actually lifted off the ground.
G-E: (2014-06-12 05:37:37)
Your rollcenter changed [archived image: smile.png]
NissanEgg: (2014-06-26 02:14:11)
Would softening the rear swaybar (smaller) make it less likely to lift the rear wheel? I do know that it would change cornering dynamics.
G-E: (2014-06-26 02:23:35)
Yes but fixing the rollcenter would do it more effectively… a lot of racecars run stiffer springs and no swaybars
What have you got in the front now?
frostvectron: (2014-06-26 03:53:42)
At that event I was running 25mm ST swaybars front and rear.
NissanEgg, other people had suggested to me the same thing. I swapped out the rear bar for the OEM non turbo one. It seems to have helped but I still lift it.
People have basically told me to give the front a higher spring rate and get the most giant front bar I can find for it. As for rates, I am running 9k/7k but I think it needs to go up to 12k or 13k and 8k.
G-E, I miss my RCA's [archived image: frown.png]