Forums/Z31P/z31-performance-upgrade-forums suspension-chassis-and-brakes/Damper settings on your coilovers
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frostvectron: (2013-06-05 05:18:18)
Welp, got my powertrix coilovers on my car!
I am curious to know what everybody is running for their damper settings. Right now I am on 8F/8R just for testing purposes (15-way adjustable).
What is everyone running (and for what application?). Anyone have any good info on how to identify a good setup?
Powertrix recommendations for the Z32:
I'll be driving at a "test and tune" event for autocross in a week and a half. I hope to go through a variety of settings and try to find what works well. Would be cool to see what everyone is running on so I can start building up some intuition though!
adamvann3: (2013-06-10 03:20:51)
Im on 9/10k I believe and running 3/4 stiff front and back. Rears I still play with front time to time as it depends on wheel and tire setup. Fronts I never touch.
frostvectron: (2013-06-15 23:18:52)
Hmm… okay, did some testing today. Tested autox with Hankook 225/50/16 V12 EVOs (40 psi front / 37 psi rear) and and old set of Bridgestone Pole Position S-03's (37 psi front, 36 psi rear). Also, I'm on 9kg/mm front and 7kg/mm rear.
Started 8/8 (out of 15) as the starting point.
I tried 8/6 but I didn't like it. It felt neutral but I felt like the car wasn't rotating very nicely.
I went to 8/10 and this set-up was very fun to drive. It rotated easily and had good turn in.
I then tried some other junk later in the day. I tried 10/10 and 10/12 but I didn't like it as much as the 8/10.
I tried a 6/8 and 6/7 which felt pretty good for these less grippy tires. When I run the Direzza Z1's tomorrow I'll try 6/8 first and maybe try the 8/10 again.
I get some "wheel hop" from the rear around some corners. What does this mean for damping? I am thinking the inner rear is lifting a bit. I was lower on fuel that usual, so hopefully this helps keep the rear down. I also lowered the car in the rear by 5mm to try and get it more planted.
G-E: (2013-06-15 23:48:04)
This is where separate rebound adjustment comes in handy [archived image: smile.png]
Since you've already got a feel for the damping, why not play with swaybar sizing now?
frostvectron: (2013-06-17 03:35:30)
I'm running the 1" sways on front and rear at the moment. I think they are old ST ones but not sure (gray in color). How do you place with sway sizing? Fabbing or trying combinations of factory/aftermarket ones?
I ran the Direzza Z1's today at 31/30 psi front/rear. I did 8/10 on the coilovers and it felt fantastic!
G-E: (2013-06-17 06:48:05)
Think of it this way, your tires (whatever you run) have a maximum amount of grip or capability, the higher that maximum, the more load you can transfer from the chassis to the tires.... overloading the tires just makes them overheat, wear faster, slide more etc
By load I mean: every chassis has give, every bushing deforming, every frame rail twisting, every spring compressing -- that give absorbs some of the ultimate load of whatever you are trying to do, each time you strengthen one area, you move more load to all the remaining areas, and so on, until you reach the tires, they are the last stop
Since we all don't have professional race teams with fea analysis and unlimited modification budgets, realistically we are only going to play with a few aspects of the chassis -- minor ones like springs/shocks/bushings, to major ones like strut bars/frame connectors/roll cage -- and they'll likely all be done at one time
Anyway to answer your question, the stock swaybars for various years already vary from 21-24mm in the rear, and are easy to obtain, probably for very little cost, probably your only real option… especially since we don't have adjustable rear aftermarket bars available (unless you magically find some koni kit like jason did)
I think in your situation any stock rear bar will be good enough to test, see if softening it helps or hurts the balance of the car, if it helps, then you can explore other sizes in the range, or fab up some custom clamp/endlink to allow adjusting your bar stiffness
BTW welding longer tabs to the end of the swaybar is acceptable too, it won't ruin the elastic section between the mounts, and there isn't that much stress on them (be very surprised if the stress exceeded 300lbs)
88Turbozx: (2013-06-17 07:57:15)
I'm on 9k 7k Powertrix coils and it seems that 8 front and 7 rear is perfect for gripping with 265/35/18s all around on continentals with the rear slightly lower than the front. I had the same damping before I balded out my Pilot sport PS2 255/35/18F 285/35/18R and it probably could have been a little stiffer for those tires. I found my "sweet spot" for ride height is 3 1/2 inches from the top of the lower spring mount (ring) to the bottom of the coilover ring that tightens to the bottom mount in the front, and 1 3/4 inches between those in the rear.
badboyz31: (2013-06-17 20:53:10)
I'm on Stance Pro SS-D coils, with 12k springs all around, and have mine 10 clicks to the hard side on both front and rear. This is on 15way adjustable's also, its stiff as hell on the street but fun as hell on the track
michaelp: (2013-06-17 21:10:12)
I'm running 9 towards the hard side with my Powertrix coils with 9k/7k springs…I like it.
frostvectron: (2013-07-21 18:11:56)
Okay… after putting some more autox's on the coilovers, I think I am running too stiff on damping.
8/10 and 8/8 make the car really harsh over bumps on the track. On corner entry it isn't so bad--just makes things a little dicey due to instability during trail braking. On corner exits it hurts quite a bit because I am losing traction when trying to accelerate after the apex. Maybe I should have done the 8k/6k spring rate combo instead of the 9k/7k.
I will try the next event with less damping and see what happens.
G-E: (2013-07-21 20:34:24)
Unfortunately the trail braking issue is most likely your semi-trailing arms doing nasty toe changes on you…
Have you swapped swaybars and tried playing with damping settings again?
frostvectron: (2013-07-22 01:34:08)
I have not swapped sways around yet.
I am thinking of raising the car a little bit and reducing the damping. Today I drove a little on the street with the rears at 5 and the ride felt a lot smoother.
G-E: (2013-07-22 02:00:16)
You can try the reverse too, stiffer rebound damping in the back, and less swaybar… possibly even lowering rear ride height could help? The closer you can keep the trailing arms to level during the turn (including the droop when you shift weight forward), the less your toe will change
BTW are you finding it happening on lefts and rights? You could bias the swaybar…
frostvectron: (2013-07-22 02:16:35)
Lowering rear ride height? I was wondering if I had gone "too low" and pushed my alignment too far from spec.
I am finding it on both left and right handers. Honestly the suspension works great if the surface is really smooth. It is just that some parts of the course I run at has rough patches with bumps. The car doesn't appear to handle badly because of the suspension itself, but more because it isn't coping with the poor surfaces very well. Corners on smooth parts of the course are no problem.
G-E: (2013-07-22 04:32:11)
If you have to go soft, go soft… you might wanna back down on tire pressure a tad too as you'll be putting less load on them
frostvectron: (2013-07-23 01:44:01)
Thanks G-E. I'll report back in a few weeks! I am thinking 3 or 4 front and 5 rear (similar to Powertrix's recommendations for the z32 autox setup).
frostvectron: (2013-08-21 19:53:33)
Okay.. after more testing, here is what I found at the last few autox events:
3 front / 5 rear = Too soft. I felt some oscillations after going over bumps.
4 front / 6 rear = Pretty good. Probably as soft as you could go before you feel oscillations.
5 front / 7 rear = Good. Rougher ride (both track and street) than the 4f/6r, but more crisp feeling while slalom-ing. Not so stiff that it produces hop/instability on trail brake (like 8f/10r).
Testing done on 235/45/17 Direzza Z1 Star Specs at 32 PSI Front / 30-31 PSI rear; Powertrix 9k/7k RT coilovers.
G-E: (2013-08-21 20:04:48)
These results are with the spacers too right? What's your camber set to?
frostvectron: (2013-08-21 22:04:04)
Yes these are with G-E's negative RCA's. Camber is max negative up front (i.e. I didn't actually measure…).
frostvectron: (2013-08-22 04:45:06)
Bleh, don't mean to double post, but I just thought of more information but the edit button has disappeared.
The 5f/7r is a fairly neutral set-up. It turns well and it can under and oversteer depending how you push the car. If you trail brake it will rotate, but not go sideways right away. If you trail brake hard, the back end will come out a good amount.
If you are looking for a more understeer/stable set-up, maybe 6f/7r or 5f/6r is a good starting point. If you want more oversteer, I'd try something like 5f/8r or 4f/7r.
In hindsight, 8f/8r and 8f/10r seems like… crazy overly stiff.