Forums/Z31P/z31-repairs-forums suspension-chassis-and-brakes-aa/Reducing Sway and Body Roll
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BlackBeast: (2014-10-12 18:46:39)
Hey Everyone,
I'm wondering what I need to do to reduce my sway/body roll. It was really bad with the OE, but since then I put in new NAPA dampers f/r, poly bushings, and new springs around 235 lb/in. on the front and 210 lb/in. on the rear. This has helped a lot but it still isn't enough for me. Not only do I have major body roll, it seems almost impossible to oversteer, and its really easy to understeer. So, I guess what I'm asking is what is the next thing, that you guys think, I can benefit most from.
Thanks
Augustus Maximus: (2014-10-12 21:10:31)
These might help
http://www.thezstore.com/page/TZS/PROD/23-4104
BlackBeast: (2014-10-12 21:43:34)
So, that's what you would get if you were in this situation?
greg84ae: (2014-10-12 21:46:51)
The MSA sway bars made a HUGE difference on my AE; chassis is so much stiffer that the ride is actually a bit too harsh, actually.
reddzx: (2014-10-12 21:57:09)
Ditto for the MSA sway bars, I've had them an two of my cars and they make a huge difference.
862sik: (2014-10-12 21:59:19)
Those are a great upgrade. But I went with late model turbo rear and front sway bar paired with poly endlinks and some custom cromoly links that I made. They are not as thick as shiros or MSA but they helped quite a bit. I have ST springs and poly bushings all the way around, those sways helped a TON! It cornered great before, but with the sways it felt so good!
Another part of sway is the tires sidewall stiffness also.
BlackBeast: (2014-10-12 22:42:00)
Sweet, thanks for all the feedback!
NissanEgg: (2014-10-13 02:19:05)
Search around for the Z3R springs that are discontinued. They are the best springs ever made for the Z31. 300 lb/in fronts and 325 lb/in rears. They pop up for sale from time to time, and if you have the cash when they pop, buy them immediately.
frostvectron: (2014-10-13 04:41:13)
NAPA dampers are probably not working enough to fully enjoy those springs.
For the trouble/cost/relatively-marginal-benefit of buying Z3R's and the dampers to properly match those rates, I would just go straight to powertrix/stance.
The MSA bars are a good, cheap bolt-on in the meantime that you will eventually want anyway so give that shot first.
862sik: (2014-10-13 04:52:08)
which brings to question, you said you got new 235lbs springs....what springs are those....?
And definitely yes, you probably just got oem replacement dampers that do squat for performance.
adamvann3: (2014-10-13 17:35:43)
What wheel and tire setup are you running
MSA sways will be your best bang for the buck to reduce body roll.
Justin,
I actually ran the 22mm sway in the rear and now have removed it all together. I have not had the chance to go thrash on the car yet, but I am hoping for some added corner traction. On the shiro I still have in the rear shiro sway, but the car is very oversteer happy. I will probably downgrade to the 22mm bar I have laying around to see if it helps.
frostvectron: (2014-10-13 18:41:30)
Justin,
I actually ran the 22mm sway in the rear and now have removed it all together. I have not had the chance to go thrash on the car yet, but I am hoping for some added corner traction. On the shiro I still have in the rear shiro sway, but the car is very oversteer happy. I will probably downgrade to the 22mm bar I have laying around to see if it helps.
Hey Adam, I found the same in my setup. The MSA rear sway made the car very tail happy on corner entry. I am running the 22mm bar in the rear right now too. I like this set up. I haven't tried no rear bar yet, but fear it might feel too pushy for me.
Bremsen: (2014-10-13 19:41:24)
I agree with others that these cars are really undersprung. I've been running MSA front and stock rear sway in the dry. Took stock rear off for last event due to lots of rain and then ran a dry test day w/o it. You can feel the rear roll more, but still didn't notice any push (even in the wet) and definitely increased rear grip. I'm sold on running w/o it during wet events, but will test in the dry again once I get the new motor installed. I think I prefer the OE bar in the dry.
YMMV, my car is about 500lbs lighter than a street car. 255 tires on 17x9s. Frost, you might not like it on an autocross when you need quick transitions and the rear to rotate a little more.
BlackBeast: (2014-10-13 20:18:16)
Question: which brings to question, you said you got new 235lbs springs....what springs are those....?
Answer: Basically didn't want to buy used SS springs for the price people were asking so, I looked on NAPAs website for an option. They only had rear springs though http://www.napaonline.com/Catalog/Ca…400_0209698605. The fronts then aren't even for the 300zx, my friend, worked at NAPA, brought the spring, not the season, catalog to my shop so I could find something with a desirable rate, but the right dimensions.
Question: What wheel and tire setup are you running
Answer: Just put some Starion 16x8 wheels wrapped in some used 225/50/R16 Hankook All-Seasons off my friends SRT-4, but before I had the stock 15x6.5 with 205/60?/R15 Goodyear Eagle GT
I don't know if it's worth mentioning, but I'm also running an OBX helical differential, Shit Is Good.
Thanks again for the input, and I was curious are progressive rate springs not good performance wise? A trusted friend told me to stay away from the Eibach lowering springs.
FrozenZ: (2014-10-13 21:19:53)
If he said "Eibach lowering springs" he probably doesn't know what he's talking about. One of the z31 sites said a million interwebs years ago that Eibachs weren't any good and now everyone just mindlessly repeats it. Eibach makes a progressive kit for z31s which in my experience is excellent for hard street and backroad driving and pairs very well with Bilstein dampers. I replaced quite new OEM springs with them and they were definitely a performance improvement. People who want to feel full racecar will probably find the initial travel too soft, but full racecar can get old real fast. They lower the car about half to three-quarters of an inch.
BlackBeast: (2014-10-13 21:53:23)
He wasn't questioning Eibach's quality, it was simply because they were a progressive rate.
frostvectron: (2014-10-13 22:54:06)
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.
BlackBeast: (2014-10-14 00:24:12)
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.
adamvann3: (2014-10-20 14:47:31)
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.
Urstin: (2014-10-20 15:38:20)
^ 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.
FrozenZ: (2014-10-20 16:11:43)
+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.
G-E: (2014-10-21 11:09:04)
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
G-E: (2014-10-21 11:16:44)
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 [archived image: smile.png]
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
frostvectron: (2014-10-21 15:36:13)
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 [archived image: smile.png]
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.
Bremsen: (2014-10-21 16:48:21)
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.
BlackBeast: (2014-10-22 17:02:05)
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!
mtherkamp: (2014-10-22 17:53:40)
^ 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.
Trbulnt: (2014-10-22 19:07:20)
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.
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!
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.
BlackBeast: (2014-10-22 19:51:37)
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!
BlackBeast: (2014-10-22 19:59:50)
[archived image: yt_logo_rgb_light.png]
Pace: (2014-10-22 22:17:50)
There is no way your 0-60 was .21555 seconds. Sorry but thats just not happening. That may be your Reaction time.
Most likely meant a 2.1555 60' time. Pretty standard for street tires and a mid-14 second time. Whether he doesn't understand it or just put the decimal point in the wrong spot is up for question.
Either way, two tenths of a second to cover 60 feet of ground is beyond the reach of a humble Z31. Lol.
To the OP, get the diff mount. It's worth the price, especially if you get the subframe bushings at the same time. ASCO ran a deal on them a while back. Maybe keep an eye out for something similar in the future.
Trbulnt: (2014-10-22 23:36:10)
Most likely meant a 2.1555 60' time. Pretty standard for street tires and a mid-14 second time. Whether he doesn't understand it or just put the decimal point in the wrong spot is up for question.
Either way, two tenths of a second to cover 60 feet of ground is beyond the reach of a humble Z31. Lol.
To the OP, get the diff mount. It's worth the price, especially if you get the subframe bushings at the same time. ASCO ran a deal on them a while back. Maybe keep an eye out for something similar in the future.
Yes that seems more likely which is why I wanted a pic of the time slip. Sadly I sold those drag radials but I do have a set of weld wheels that will eventually get a new set of radials once my car is done.
BlackBeast: (2014-10-23 01:03:42)
Sorry, I did mean 2.155 seconds, sorry about that.
Trbulnt: (2014-10-23 11:16:54)
Sorry, I did mean 2.155 seconds, sorry about that.
No need to apologize. Your excitement clearly comes through in your posts! A 2.1 60 is good on a street tire so be proud of it still!
BlackBeast: (2014-10-28 01:21:57)
Thanks and I will be [archived image: biggrin.png]
BlackBeast: (2014-10-28 02:28:50)
10708782_10154867808565647_1627970306778677735_o.jpg
A picture from the last auto cross.
harwood909: (2014-10-29 01:09:50)
Is your friend with the 350z named Robert by chance?
BlackBeast: (2014-10-29 13:41:12)
Hey Shane! And no my friends 350z is bonestock, however we did talk to Robert and Tom.
harwood909: (2014-10-30 00:02:55)
im sorry if im ignorant but what is your name? lol
BlackBeast: (2014-10-30 00:17:28)
TJ I'm one of Joey's roommates. lol
harwood909: (2014-10-30 01:46:16)
ahhhhhh now I know. It's hard on the forums, everybody has two names
BlackBeast: (2014-10-31 04:43:32)
I know what you mean! lol
BlackBeast: (2014-12-24 19:35:12)
Here's a small video of my friends and I auto crossing.
[archived image: yt_logo_rgb_light.png]
mtherkamp: (2014-12-25 03:15:05)
Wow that's awesome, cool footage, bonus points for cards against humanity!
BlackBeast: (2014-12-27 07:02:56)
Raw autocross video!
[archived image: yt_logo_rgb_light.png]
PrideZ31: (2014-12-27 15:10:03)
Just installed MSA's on my Z today! The difference is night and day. Car corners harder but once that tail is out, it's out. Tightened up that 196Kmi suspension a hell of a lot too. My friends and I were having fun tossin the stock sways bars back and forth becacuse of the weight difference of MSA vs stock.
floridaZ: (2014-12-28 20:06:03)
I have MSAs on my Z, never had a problem getting the tail in line. I have coils though.
BlackBeast: (2015-04-07 18:12:10)
Would it be more beneficial to go with tires (RS-3, Z2, and like tires), or to upgrade the sway bar? I feel like the stickier tires may induce more body roll which could slow me down on the autocross, I'd like to do both but that may not be an option.
NissanEgg: (2015-04-07 19:20:25)
I would go with big rear bar and more rear tire for better grip too out of the corners. They kind of cancel out the negatives of each other. The bigger rear bar will help the rear to rotate more, and the wider rear tire will help to counteract that and give more grip too. Still will make the car "feel" more nimble and eager to turn.
What symptoms are you experiencing? Tail out powering out, tail out under braking, or understeering everywhere? Lots of different ways to tune the handling by mix/matching parts or taking parts off.
jaqattack02: (2015-04-07 23:05:39)
Have you checked the rules for your class? Can you change the sways without getting reclassed? Assuming that is something you care about.
frostvectron: (2015-04-08 01:36:43)
Autocross? Stickier tires will ALWAYS be faster, regardless of how much body roll you have. In my experience, the rear bar will not help body roll--it's the front bar and front spring rates that affect body roll.
The rear bar will help the car rotate, but it will also cause you to lift the inner rear wheel if you're holding enough lateral G's.
From your video a few posts up, it does not look like body roll is your problem. At least from the video, the car's roll doesn't appear to be excessive.
Remember: roll means you are gripping the surface enough to get the car to deflect. Lots of roll could either mean your suspension is soft and squishy or you are holding a shit ton of G's because of awesome grip. If you put junkyard tires on your car, you will not have any roll whatsoever while cornering, but you'll lose traction without holding any kind of cornering speed.
BlackBeast: (2015-04-09 13:41:16)
The classing isn't really important as it's more about me and my friends competing, but I wouldn't change class. Second it's hard to say how the car acts because when racing on the 1/4 mile circle tracks the car seemed to under steer, but then at the miller park parking lot the car was tail happy. I'm not sure if it was just the way I was driving or the race course surface, you know what I mean?
BlackBeast: (2015-04-09 18:09:53)
Frostvectron,
Thanks I see what you mean, what tire do you use? My one friend is putting RS-3s on his 325is and my brother is putting Z2s on his Camaro.
frostvectron: (2015-04-09 19:32:45)
Course surface will definitely affect how the car will feel. I am not surprised the car feels differently between your two different venues. I run different damper settings and tire pressures for different venues as well as different ambient temperatures.
I use a lot of different tires… last year I tried: Hoosier A6, Hankook C71, Kumho XS, Direzza Z1 Star Specs, Falken 615, Toyo R1R, Hankook RS3 and maybe some others. If you're sticking with street tires, any of the 200TW autox compounds would suit you well.... each have little quirks and perks (and prices), but those are sort of nitpicky details that only matter once you start splitting hairs over time (and also depends highly on your surface and temperature). Hankook RS3, Dunlop Z2 Star Specs, Toyo R1R, BFG Rival-S, Bridgestone 71R are the big names right now. The Bridgestone 71R really made a fantastic showing at the SCCA National Tour in San Diego and is sort of touted as the magic tire. They wear extraordinarily fast compared to the others though, so if you plan to go that route I wouldn't daily on them.
BlackBeast: (2015-04-21 04:14:07)
Just ran the first autocross from the season, definitely need better tires, I couldn't stop killing cones. But got a real good feel for the car!