510 Front suspension questions..

[510revisited]

So I've rebuilt my front suspension with a bunch of new parts. All new ball joints, steering linkages, and poly bushings. I've chopped my 510 strut housings for a ground control coilover kit. I'm running 79 280zx kyb struts, brand new. Rear has nothing new except kyb shocks, all old nasty bushings. I took the car out for a spin today, and also a few weeks back and the thing is so darn bouncy in front it feels like I'm riding on springs only. 200lb springs btw. And to clarify, what I'm leaning towards for use is, some track day, occasional daily.. I'd like it to be like it was a sport option from nissan in 69. A little stiff, but not race car. Just a wee bit sportier. I have coilovers for the rear going on this weekend with 200lb springs, so I'll see if it was just a balance issue, but I'm not holding my breath!! Any and all help is much appreciated 

 

Edit: Forgot to mention, I have it sitting pretty low, could that be an issue too? I've never had coilovers before. I understand the concept, idea, negative thoughts, and positive thoughts of them as well. Again, thanks. Sorry to beat a dead horse too!

 

Edited January 17, 2020 by 510revisited

[datzenmike]

Try running the tires just above their minimum air pressure.

 

Not at all a fan of poly bushings. Too hard and transmit vibration. Did you tighten the bushings down with the car at final ride height and on it's wheels?? Important that you do. Did you use poly on the tension rods??

 

Maybe a 175 lb/in spring would suit you better. I have 150 lb/in. on my 710 and like it a lot, yet some run 225 and more. Track 510s are over 300!!!

[510revisited]

I did NOT tighten the bushings down with the car on the ground. I had meant to mention that I did the same thing with the sway bar. Mounted it to the end links with the car on stands. I've heard both that is and isn't a big deal. 

Oh and no, just new rubber on the Tension rods

Edited January 17, 2020 by 510revisited

[datzenmike]

You say it rides funny so everything done recently should be looked at.

 

Well if the suspension was at full droop and the bushings tightened then they will be under torsion when he car is lowered. When rubber ones are replaced they are tightened when the car is on it's wheels so the rubber is at it's 'rest state' and free to move equally either way as the suspension flexes. 

 

Good on the rubber tension rods bushings.👍

 

Sway bar shouldn't matter, there's no twisting involved.

[carterb]

Are you still running stock seats?

I have noticed firm suspension makes a 510 seem VERY bouncy with stock seats but not so with firmer buckets. 

--carter

[510revisited]

On 1/16/2020 at 10:15 PM, carterb said:

Are you still running stock seats?

I have noticed firm suspension makes a 510 seem VERY bouncy with stock seats but not so with firmer buckets. 

--carter

I am running stock seats. I bought 240z seats, but I didn't realize the dont fold forward enough to allow a passenger in and out of the back. 

I'm not discounting your advice, but this thing bounces so bad it's hard to even use the gas pedal... I have a 3 days weekend, so I intend to jack the car up onto ramps, and I will redo all the bushings as per Mike's advice..

[thisismatt]

If you did poly bushings in the lower control arms then it shouldn't matter.  Poly bushings don't adhere to the races, they just spin, unlike OEM rubber bushings that are meant to twist and should be tightened at normal ride height.

 

If you replaced the T/C mount bushings with poly you should reconsider, as this is too stiff and will result in the T/C rod bending and possibly breaking.

 

Do you strut inserts have any adjustment?  Bounce is usually attributed to shocks that can't dampen the springs well enough.

[510revisited]

44 minutes ago, thisismatt said:

If you did poly bushings in the lower control arms then it shouldn't matter.  Poly bushings don't adhere to the races, they just spin, unlike OEM rubber bushings that are meant to twist and should be tightened at normal ride height.

 

If you replaced the T/C mount bushings with poly you should reconsider, as this is too stiff and will result in the T/C rod bending and possibly breaking.

 

Do you strut inserts have any adjustment?  Bounce is usually attributed to shocks that can't dampen the springs well enough.

See, that's what I was thinking too. Maybe the struts are defective... idk. They are BRAND NEW, out of the box. Non adjustable. In order to run adjustable struts, do I need to run camber plates, or no? Btw, I used rubber on the T/c rods. I did my research before I jumped into all this. 

[datzenmike]

1 hour ago, thisismatt said:

If you did poly bushings in the lower control arms then it shouldn't matter.  Poly bushings don't adhere to the races, they just spin, unlike OEM rubber bushings that are meant to twist and should be tightened at normal ride height.

 

 

 

This is one of the reasons I don't like poly. If it spins on one surface there is wear, the others are squeaking and transmitting vibration all because the material is too stiff. Rubber grips both parts and will give internally if twisted or compressed. Far and away most people don't, can't or have no where to drive their car hard enough to feel any gain from using poly bushings over new rubber ones but they will notice the down side to them. Now if a track car, that runs at the outer edge of suspension performance, the advantages outweigh the disadvantages... and they are inspected and replaced regularly.

 

The stock spring rate for a 510 is 89 lb/in so doubling the rate to 200 lb/in may be too much for you. There's no correct rate, only what you are comfortable with. For example I was at 100 lb/in on my 710 but really like the firmness of 150 lb/in and lowering about 2- 2 1/2". I tried lower like everyone else but quickly tired of constantly bottoming out and tires scrubbing the fenders.

 

Moderation in all things. Driving should be fun and enjoyable.

[thisismatt]

1 hour ago, 510revisited said:

See, that's what I was thinking too. Maybe the struts are defective... idk. They are BRAND NEW, out of the box. Non adjustable. In order to run adjustable struts, do I need to run camber plates, or no? Btw, I used rubber on the T/c rods. I did my research before I jumped into all this. 

 

I don't know 280zx spring rate off the top of my head, but maybe 200lb springs is too stiff for them to handle.  Do you have bump stops?  How much compression do you have before you bottom out at normal ride height?  Maybe increase the ride height by an inch and take it for a test to see if the ride improves.

 

[510revisited]

12 minutes ago, thisismatt said:

 

I don't know 280zx spring rate off the top of my head, but maybe 200lb springs is too stiff for them to handle.  Do you have bump stops?  How much compression do you have before you bottom out at normal ride height?  Maybe increase the ride height by an inch and take it for a test to see if the ride improves.

 

I have bump stops. dont know how much compression it has. I'm gonna go lift up the front about an inch or so, and install my rear coilovers.. maybe just lift the front end first... I appreciate all the help. Like mike said. It should be fun to drive.. and I know it was at one point

[thisismatt]

Well, I would think it would feel bouncy if it's sitting on the bump stops 😛

[datzenmike]

31 minutes ago, thisismatt said:

 

I don't know 280zx spring rate off the top of my head, but maybe 200lb springs is too stiff for them to handle.  Do you have bump stops?  How much compression do you have before you bottom out at normal ride height?  Maybe increase the ride height by an inch and take it for a test to see if the ride improves.

 

 

Matt, I just went out in the snow to my pile 'o parts and did some quick but accurate measuring of a ZX strut coil spring. I got 3.4 active coils, 0.525" thick wire and 5.875" width of coil center to center. A little X and / and I get 162.08 pounds/inch.  I have a set of Maxima coils and years ago they worked out to 150 lb/in so confident this is good.

[510revisited]

1 hour ago, datzenmike said:

 

Matt, I just went out in the snow to my pile 'o parts and did some quick but accurate measuring of a ZX strut coil spring. I got 3.4 active coils, 0.525" thick wire and 5.875" width of coil center to center. A little X and / and I get 162.08 pounds/inch.  I have a set of Maxima coils and years ago they worked out to 150 lb/in so confident this is good.

Well, I wanna thank everyone for the help and input. I took the easy route and jacked the coilovers up one inch both sides, and GOD DARN IT that made all the difference in the world. So much so, I decided to go ahead and install my rear coilovers! But alas, my luck caught me up. In my excitement of removing the old spring, my dumbass lowered the control arm too much. Now I get to install new brake lines! (I only busted one, but I'm sure it'll happen again, and two is ALWAYS better than one. Right?) So, I plan to finish the coilover install, stable the damn thing, and wait on MOAR parts.... fml. 🤬🤣

[thisismatt]

I would suggest you pull the spring off one side one the front and cycle the suspension to find out what's bottoming, and then make corrections from there.  Hopefully it wasn't the insert itself

[datzenmike]

You can't lower indefinitely. On a stock strut, even a zx, you can get so low you have bottomed out the insert. Once it's bottomed out the tire becomes your suspension.

[510revisited]

7 minutes ago, datzenmike said:

You can't lower indefinitely. On a stock strut, even a zx, you can get so low you have bottomed out the insert. Once it's bottomed out the tire becomes your suspension.

I get that. I just didn't realize it was THAT low. No worries. Lesson learned. Like mentioned originally, this is my first time lowering a car "properly". I've always just chopped springs. Now I can't wait till 1230 tomorrow when I get to install a new brake line! Yeah.... 🤬🤬🤬🤬