Reducing Sway and Body Roll

He wasn't questioning Eibach's quality, it was simply because they were a progressive rate.

Bremsen, thanks, good to know! I will have to try it without a rear bar sometime.

My recommendations for the OP:

1) Get the MSA bars. Try the car with both on and see how you like it. If it feels too tail happy, try the stock rear bar with the MSA front bar.
2) Still unsatisfied, do either of the following depending on budget and goals:
--a] Go straight to coilovers
--b] Get better dampers that are more suitable for those stiffer spring rates (Tokico Illumina, Bilsteins, even Tokico Blue shocks are going to be an improvement)
3) Try G-E's offset bumpsteer spacer to get more front negative camber to make understeer go away.
4) Better tire set-up.

Alright sweet, and don't worry I'm already looking RS-3's, and I feel like Bilsteins would work best, but what about Koni's?

Thanks again for all the help.

I have a set of Eibach's + Tokico HP struts on my 86. Huge improvement over stock setup and keeps the very firm and predictable but still very practical for every day (matched with 17x9 245/45/17). In my opinion, these are what the cars should have come with stock. My only complaint is the lack of front camber. In flat corning, or even worse off camber turns the outside tire likes to loose traction. More camber would largely help the situation.

I also have a car with full coilovers and a bunch of other adjustable suspension. Large improvement in the handling and grip department and will handle anything I throw at it, more so that I needed a new seat for more lateral support. However it does compromise the comfort of everyday driving. More so in the rear, but that could be a matter of me having rear rebound not adjusted correctly.




To answer your above question, Bilsteins are the best aftermarket strut for the car. While Koni's are good as well, I have seen them blow out pretty quickly and need to go through warranty replacement after a couple of years.

If you have not done so already, make sure you have replaced your rear cross member bushings along with the differential mount bushings.

To build upon Justin's list:
1) Better dampers (bilstein discussion)
2) Bushings - Rear cross member, differential bushings, FLCA, and tension rod bushings
3) Something to dial in more camber up front, GE offset BSS seem like the best bang for the buck to solve a few issues
4) Front Sway bar

I think that combination will resolve what you are looking for. The other part of the equation is wheel size and tires. 225/50/16 will be a large improvement over stock setup.

^ And to build off Adam's post!

My 85NA has:

Polyurethane Swaybar endlinks and bushings (Front/Rear)
Polyurethane front control arm bushings
New balljoints
New front strut mounts (these can be had for cheap and make a huge difference)
Bilstein struts front shocks rear
New inner/outer tierods (for what it's worth)
86T rear springs w/ polyurethane seats

So I've done essentially everything mentioned above BUT the differential mount and crossmember mount. The difference is insane. I have leather seats, so my ass does slide a little when cornering at higher speeds, but the level of comfort is ALMOST on point. Before my car would sag and tilt as I shifted. After replacing the strut mounts and rear shocks, this fixed that immediately. I do still hear some clunking in the rear over some bumps, but this is much quieter than before. My assumption is that the rear crossmember mounts will fix that issue.

I'm on stock 85NA wheels, with General Acclaim UHP tires (roughly 9k miles on them). I DD my car, and have put 16k on it in the past year, the upgrades mention above have put this car at it's most comfortable ride in probably 100k miles.

+1 on new strut mounts.

Also, I have had GE's bumpsteer spacers in for about 3500 miles and think they're great, the only issue being access to the upper bolts for the occasional torque check. Increased camber, improved ride quality and no notable difference in steering effort even with manual steering. I also don't think you're likely to need more camber for any street driving situation than they will give you.

Adjusting ROLLCENTER which is what the spacers are for primarily, will change how the body ROLLS, it changes how weight is transferred and how high a threshold you can keep…

It's like standing sideways with your legs spread apart in a really strong wind, you haven't changed the force, you've just changed the force required to tip you over -- the camber is to help with grip

So, too much roll can be tuned with a combination of swaybars and RCA kit, the RCA acts before and during roll, the swaybar along with springs lessen how much you roll -- keep this in mind when diagnosing what you need, do you roll too easily, or do you roll too much?

Side note: please stop calling them bumpsteer spacers guys, they aren't changing any steering characteristics

A great example is when frostvectron removed his RCA kit, and immediately started lifting his rear wheel in hard cornering

Having a different RC front and rear makes a lot of sense if you understand how they work together, generally having a higher RC in the rear will promote understeer, having a lower RC in the rear will reduce understeer… unless of course like frosty you lift a rear wheel, then you flip from understeer to oversteer in a second

Having a wider trackwidth in the front and narrower width in the rear will also have some the effects of a high front RC and low rear RC… the RCA kit bumps your front trackwidth by about 10mm per side

Hehe, lifting a rear wheel doesn't snap it into oversteer too bad. It's just that you don't get as much grip on throttle to exit corners--it's like going back to open diff. When you're throttling and unwinding the steering wheel and the lifted wheel lands, there is a sudden jerk as everything sort of catches. But the chances are if you are lifting, there is some serious grip going on so things don't get too out of hand.

Even with the NRCA's I still lift when I'm running slicks, but it's not nearly as bad as without. Without them, I can lift the inner rear on autox street tires.

For blackbeast, the RS3's are an excellent tire.

Might help you to remove that rear sway then frost. Especially if you can add spring rate to compensate. Lifting a rear wheel on a RWD isn't optimal.

I wish I could add the roll center spacers. I've been looking to see if I can raise up the pivot point on the subframe to get some add'l camber gain. Right now the arms sit level so as the car rolls I lose camber. I run heims up front and lengthened the arm to gain camber (about -2.5°). Made an huge improvement in front grip and tire wear, but I wouldn't recommend that much for a DD.

Ok, so I don't have the differential mount, and I know I need one, but really $200? As far as the cross member I'm not 100% sure if I have them but I'm assuming those are the same as the sub-frame bushings?

Update on how the car feels, this past weekend I was at the Great Lakes Dragaway and an autocross at Miller Park. At the drag strip the car had tons of wheel hop, but that's the only thing really worth mentioning from that. But is that just something Z cars do because my friends 350z had a ton of wheel hop as well. However, Miller Park was very useful, one thing I don't think I mentioned was that the group I autocross with, MSCC, usually holds events at 1/4 mile and 1/2 mile circle tracks and not on parking lots. Now, I can't say for sure due to the fact that I am running a different set of tires, both sets are all-seasons though, but part of the reason I was getting so much role was the track surface. On the tracks I would get large amounts of role and never once an inkling of over steer, and it felt like I never saw my cars full potential. Where as at Miller Park on an actual parking lot, it felt like I was able to push the car to its very limits, where I encountered quite a bit of oversteer.

Now, like I said the tires could be to blame for this and so could the openness of a parking lot, by that I mean no concrete walls you could spin out into, but I believe the change in track surface is what really allowed my car to show it's awesomeness. That being said I would think the wisest move would be to get those anti-sway bars and better dampers or coilovers. Any feedback, opinions, and/or questions are welcome. It will be awhile though, because after the last run, I believe my water pump is starting to seize, so now I got to replace that, feel free to leave advice on this as well, but I have a good idea of what I need to do for this.

BONUS: For those whom are interested. My best quarter-mile time was 14.856 seconds, not that fast but I did get the best 0-60 foot time, out of my group of friends, which was 0.2155 seconds. As for the autocross, they haven't posted the overall results yet, but my best time was a 1:05.700 which got me a 3rd place in my class. I was bet by a 200X Lexus something and a 2004 GTO, but the best the Lexus did was a 1:04.000. I bet a 1980's Formula, a 1998 Formula, and 1994-1998 SVT Mustang with 2 drivers. Thanks for reading!

^ if you want a poly diff mount, BUY IT. Its worth it, after building my own, major pain and lots of time taken. Otherwise, just take a piece of steel angle iron and make a solid mount.

I wanted to attend both events as TJ called me earlier in the week. A few items I'd like to touch base on. Wheel hop is an issue with the cars as the rear suspension is just not setup for hard launches. With that said I had practically zero wheel hop on my Z with the drag radials but with the street tires it was obnoxious. There is no way your 0-60 was .21555 seconds. Sorry but thats just not happening. That may be your Reaction time. Post up a pic of your time slip. What was your mph at the 1/4 mile as that will tell you more about your cars power than the time will. Sounds like it was a fun vehicular weekend.

It was an awesome weekend and that was a 0-60 Feet time not 0-60 MPH. I think my highest top speed 93.75. Hope this helps, and angle iron is something I can afford lol but how does a solid differential mount act. Chris, I should have come and grabbed your slicks lol!