For people that have replaced all or a significant amount of their rubber bushing with solid or poly, and specifically in the context of autox/track use, how large or a difference did this change make?

Is it worth the money and hassle involved? I only care about the performance. I don't street drive the car so ride quality is not a concern.

Thanks

 

Just replacing suspension bushings without upgrading swaybars, dampers and springs won't result in much performance. Think of the changes as being on a small scale. My T3-spec Z33 does use NISMO bushings, as the OEM ones were worn out years ago. Like the rest of the upgrades, they provide better feedback when you're at or near the limit.
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My Z is used for street driving and I run a mix of poly and OEM bushings. Whiteline Poly in the front suspension LCAs + Compression rod and rear differential. The rest are OEM. I definitely noticed an increase in feedback with only a minor increase in NVH (as expected I would say). Eventually I will probably replace the rear knuckle bushings with Nismo as dkmura has done.

For some areas of the suspension using poly or solid/spherical will make a huge impact for track/autocross events, while in other areas it won't be as noticeable. I think the biggest improvements can be seen from replacing the transmission mount, rear differential, and rear subframe bushings. NVH not being a concern, you could go solid, but I would recommend poly for the trans + diff and the Z1 inserts for the subframe (saves a huge amount of time/labor). I cannot comment on spherical joints as I've never used them. My Z32 friends who have used them, end up with annoying squeaks/creaks which would drive me nuts. I like the Whiteline bushings I've been running, so far no issues with squeaks/creaks or premature failures, they're holding up just fine on the crappy CA roads.

Edit: dkmura makes a good point. Upgrading swaybars + coils + struts (or coilovers), and tires will have a greater impact vs. bushings alone.

Cheers!
-Icer

 

First mod I did for track use / hpde was a z1 diff brace. Took a lot of slop out of drive train.

then I did solid diff bushings and split collar inserts for the sub frame.

result felt tighter and more responsive as the diff was now bolted to the sub frame.

not long after that I had to replace the
( prob original) rear bearings and cv axles.

Ended up with car feeling much better. The noise vibration from the solid bushings go away once car is fully warmed up.

I do have z1 front / sway bars. Can’t tell too much of a difference between these and stock.

280 TW tires

 

I have already done all of these things. I am curious if AFTER doing all of that, the poly upgrade felt worth it. Things feel a bit sloppy mid corner like I can feel the bushing deflecting or compressing almost. Then the car will actually rotate nicely. Hence why I'm asking

 

Most noticeable on my car was the subframe bushings and rear knuckles.


all bushings on my car were solid or spericle