9k/14k (500lb/750lb) sounds more reasonable for VIR. I’m at 8k/12k (450lb/672lb) and am slight loose in terms of balance with my 034 RSB on soft. 16k seems a little high unless you intend to go back to a stock rear swaybar if the car is super loose. I’m running a similar front/rear spring frequency to David. Auto-x setups are more extreme. We need to dial it back for the track. Speeds at VIR are double that of most Auto-X. I’m still working my way back to pushing hard up the esses. Late turn ins at T-10 are now punished with oversteer if you enter with high corner speeds. You’ve got to hit your marks perfectly as this setup is not forgiving. But it is definitely fast. I’m able to knock out fast laptimes consistently and extract speed from the car much easier.
I’m already lifting a rear wheel at most corners. I need to lower my rear right height. It went up 30mm with the 12k rear springs. Im getting 7” springs and tender springs to get back to stockish ride height. I’d recommend you go the same route front and rear if the BC’s have the internal stroke to accommodate the 7”/tender spring combo.
Most of the advice I would expect on this thread would come from the autocross crowd and I was aware the difference in road course to auto cross so I appreciate the advice being you know how VIR is. I think im pretty set on going 14k rear especially since my rsb isn't very aggressive at only 23mm I believe for the emd rear sway bar. I'm not getting how you're rear spring went up on overall length going to a 12k. I would think I wanna keep the same spring length? My car currently feels fairly neutral with minimal understeer. I went off at hogpen cause when the suspension unloaded on the downhill, I lost grip. I think that also had something to do with running pss tires pretty hard for 30 min sessions.
I got new wheels in and gonna put some tires on next month to prep for next season but im conflicted between 100tw or 200tw. I like that the pss tires really talk to you when you're going too hard.
I know we've spoken about this before, but those are the exact rates I run (8k, 14k) and I am pretty pleased with the setup. Alignments will change whether the car wants to push / neutral / oversteer from that point. I'd say it's a good starting point
Yeah definitely I remember our conversation and it was very helpful. I cant remember but do you also do road course? I know you autocross so I wasn't sure if the recommended rates would make the car too stiff and rotate too much at higher speeds. I was debating buying some used ohlins but idk how much of an upgrade that would really be compared to sending off the BCs to get revalved.
He was also adjusting toe as rear rate was upped, and I'd argue that the handling difference was mainly the rear toe.
What I have learned in my years is that relative roll couple adjustments only work when your rates (springs and bars) are in a good starting place. And a good starting place might not look the way you expect. I wasted thousands on my Integra learning this lesson.
With 450 front spring rate, the front is saturated and overloaded so changes to the rear rate don't do much. Rear toe and camber would still affect the balance though. So, while it sounds super strange to throw that much more rate at the front and expect it to corner better, maybe that much rate is needed to get the front to it's happy spot. The front of these cars are sooo heavy, easily seeing over 1500lbf on one side mid corner. You have to prop the front up before worrying about the rear.
Yeah this is probably a better place for this anyways. I'm still curious what the springrates would look like with more static camber. My understanding of how the program David is using works is that it's trying to limit front roll angle so that you always maintain contact patch of the tire. With less static camber you'd need more spring because you can only tolerate so much roll before you go +camber.
So while 450 might be light, I think 800 might be too far on the other side as well. Without trying to replicate all of David's work, I think it'd be a good academic exercise to see how different static camber values impact the amount of spring you need to keep the tire contact patch happy.
Yeah definitely I remember our conversation and it was very helpful. I cant remember but do you also do road course? I know you autocross so I wasn't sure if the recommended rates would make the car too stiff and rotate too much at higher speeds. I was debating buying some used ohlins but idk how much of an upgrade that would really be compared to sending off the BCs to get revalved.
Just autox for me. I wouldn't hesitate to run the springs on track though, but I'd change my rear bar from stiff to soft and add some toe-in in the back as a safety. As my car is right now, it handles pretty neutral and only oversteers if really provoked or on cold tires (this is at autox speeds, so ~60mph).
Most of the advice I would expect on this thread would come from the autocross crowd and I was aware the difference in road course to auto cross so I appreciate the advice being you know how VIR is. I think im pretty set on going 14k rear especially since my rsb isn't very aggressive at only 23mm I believe for the emd rear sway bar. I'm not getting how you're rear spring went up on overall length going to a 12k. I would think I wanna keep the same spring length? My car currently feels fairly neutral with minimal understeer. I went off at hogpen cause when the suspension unloaded on the downhill, I lost grip. I think that also had something to do with running pss tires pretty hard for 30 min sessions.
I got new wheels in and gonna put some tires on next month to prep for next season but im conflicted between 100tw or 200tw. I like that the pss tires really talk to you when you're going too hard.
You may have misread my response. 16k in the rear is aggressive. I was suggesting 9k/14k as a starting point. It’s not far off my current setup of 8k/12k. You may want stickier tires through. Michelin’s talk nice an early approaching the limits. I’ve finally got my tire pressures dialed in on my NT0. I’m getting them to talk but they are way quieter.
My ride height increased 30mm when I went to 12k in the rear. Still an 8” spring but I guess the spring compressed way less than the 8k spring I had. The increased rear ride height may also be contributing to the inside rear wheel lifting. I must be an 1” over stock rear ride height.
If you all didn't catch it in my suspension modeling thread here are my actual frequencies based on new suspension measurements at the wheel vs at the Hub.
600/1200, with my corner weights is 1.73hz front and 2.34hz rear, which is more than I want to run, right now.
My spring suggestion to @GTIfan99 is based on a much more livable 1.45hz / 1.85hz rates.
Ive got some catching up to do. Browsed through your thread quickly. I’m assuming that you have a different front motion ratio? Based on my measurements of my CSS swivels before I installed them. The offset was higher than I thought but y’all said the MR was about .98. I need to go back and check my notes.
What front MR are you using?
if I had my way, I’d dump both sways and use springs for roll control if I new what the sweet spot is in terms of spring rates, without tons of trial and error.
More static camber in the -3.5 plus range definitely helps If you can get it.
You may have misread my response. 16k in the rear is aggressive. I was suggesting 9k/14k as a starting point. It’s not far off my current setup of 8k/12k. You may want stickier tires through. Michelin’s talk nice an early approaching the limits. I’ve finally got my tire pressures dialed in on my NT0. I’m getting them to talk but they are way quieter.
My ride height increased 30mm when I went to 12k in the rear. Still an 8” spring but I guess the spring compressed way less than the 8k spring I had. The increased rear ride height may also be contributing to the inside rear wheel lifting. I must be an 1” over stock rear ride height.
Yeah this is probably a better place for this anyways. I'm still curious what the springrates would look like with more static camber. My understanding of how the program David is using works is that it's trying to limit front roll angle so that you always maintain contact patch of the tire. With less static camber you'd need more spring because you can only tolerate so much roll before you go +camber.
So while 450 might be light, I think 800 might be too far on the other side as well. Without trying to replicate all of David's work, I think it'd be a good academic exercise to see how different static camber values impact the amount of spring you need to keep the tire contact patch happy.
Ive got some catching up to do. Browsed through your thread quickly. I’m assuming that you have a different front motion ratio? Based on my measurements of my CSS swivels before I installed them. The offset was higher than I thought but y’all said the MR was about .98. I need to go back and check my notes.
What front MR are you using?
if I had my way, I’d dump both sways and use springs for roll control if I new what the sweet spot is in terms of spring rates, without tons of trial and error.
More static camber in the -3.5 plus range definitely helps If you can get it.
Yeah I saw the comparison of static negative camber to how much roll you can allow, but that would change the required springrate as well and I didn't know if you had done that part of it (or if the program spit it out)
Yeah I saw the comparison of static negative camber to how much roll you can allow, but that would change the required springrate as well and I didn't know if you had done that part of it (or if the program spit it out)
I have not made it far enough into the analysis to know what spring rate is required. I will probably run it for 1.2G and with my corner weights/springs and bars, so it won’t apply to every car/setup.
I have not made it far enough into the analysis to know what spring rate is required. I will probably run it for 1.2G and with my corner weights/springs and bars, so it won’t apply to every car/setup.
Already have adjustable rear spring platforms with my Ohlins. I’m as low as I can go before they unseat the spring. I need 7” springs with a tender spring.
Already have adjustable rear spring platforms with my Ohlins. I’m as low as I can go before they unseat the spring. I need 7” springs with a tender spring.
