I just tried a search, and no answer to this question...

I started autocrossing this weekend. My car has a tendency to oversteer a bit.

Does anyone know how to dial in their koni yellows? I have them set 1/2 in front and 3/4 in the rear.

How do you tune them so that the car is neutral?

TIA!

 

At my last event I set mine to 1 turn up front and 1.25 in the back. This setting felt pretty neutral to me.... maybe I wasn't pushing it enough. What tire pressure are you using??

 

Assuming your tire pressures are not out of whack, it sounds like you want to stiffen up the front end relative to the back a bit. It's rare that FF cars have an oversteering problem, though. Are you sure you're not just on the brakes at the wrong places? Like in the middle of a slalom?

I'm generally trying to get all the oversteer I can get, but then again, I'm in Stock class..

Edit: too many "though"s


[Modified by MechE00, 4:12 AM 2/19/2002]

 

Please remind me again of what the spring rates are on the Eibach Prokit. Properly dialing in your Koni's will have a lot to do with that. Also important is the kind of autocross course you will typically run on. On courses that are open and fast, you'll be able to dial in more firmness than on courses that are tight w/ quick transitions, and slower in speed. Of course it all depends on your driving preferences, but most of us autocrossers are looking for a car that feels neutral or oversteers just a bit. I currently set mine at 3/4 turn up front and 1 full turn (sometimes 1.25 turns) in the rear with my Comptech Sport springs (330F, 210R). And I still can't get the car to rotate like I want it too, which is why I'm thinking about getting some custom spring rate GC coilovers with more evenly matched spring rates. HTH.

 

Wouldn't you want more firmness on the course with quick transitions? Why would you worry about firmness on an open course? On a tight course w/ quick tranistions, you want the car's response to transients to be as quick as possible, thus a stiffer setup. On an open course, you can allow for a slower response time from your car in order to grab that little bit of extra traction the softer settings may be able to find. Or at least that is my understanding..

Making one end more stiff relative to the other makes that end more likely to break free sooner. Of course, tuning with shocks only has effect really during transitions-- at steady state, shocks are invisible, suspension-wise. Further stiffening the rear shocks may help your rotation at turn-in.

 

Mech, good question. Here's my limited understanding and experience on things... When you dial up the firmness on the Koni's, you're adjusting the rebound and actually delaying the time that the shock returns to it's normal length after it's been compressed. On a tight course with a lot of quick transitions, back and forth, side to side, if you're too firm then the shock will not have fully rebounded before called upon to compress and rebound again. The net result of this is a car that is slow to respond to steering inputs, kind of lack driving through thick molassas. That's why on a course with quick transitions you want things to be a bit looser from a rebound point of view.

edit: somehow I submitted this reply before I was finished...

I agree that you want to stiffen up the end you want to break free sooner. I tried going full firm on the rears a couple events ago and it made my car more plow-happy than it already is. And is was really slow going through the slalom due to the reasons mentioned above. The advice I've received for those more experienced and knowledgable than me is to go as soft as you possibly can on the rebound setting in the rear of the car to help it rotate. My limited experience also bears this out. Now if you've got D/A Koni's, the compression setting is an entirely different matter.


[Modified by Neo, 9:13 AM 2/19/2002]

 

I have heard of this being referred to as "jacking down".. the main problem of which is that you may end up "jacking down" so much that you use up your shock travel and bottom out, resulting in a suspension short, so to speak..

Unless there is something I am missing on the internal details of the Koni shocks, jacking down shouldn't change anything about the shock's bump or rebound characteristics unless it has run out of shock travel.

I don't understand how this could slow the car's response to steering inputs. Quick weight transfer and rapid damping of body roll (thus a rapid stabilization of vertical forces on the tires) are what I would consider to be halmarks of quick response to steering inputs. I don't understand how stiff rebound settings could be detrimental to this effect unless jacking down produces a short. Surely a severly overdamped system would also have a long settling time, but that sort of settling would be a slow, steady decay instead of the undesirable oscillation seen in an underdamped condition.

This goes against my experience. Certainly I have had events where the car just plows like crazy.. sometimes it's the surface I'm on, sometimes it's tire pressures, sometimes it's my driving (heh.. mostly it's my driving ). In my experience, a lighter, stiffer rear end makes for more oversteer. And I've never experienced a "molasses effect" with stiffer shocks settings.

How do you determine "as soft as you possibly can", then? This is very confusing advice to me because it does not agree with my understanding of the systems and dynamics involved.

I am running Koni Yellows..

Edit: too many "have"s


[Modified by MechE00, 6:39 AM 2/19/2002]

 

Not heard of "jacking down" before, but what you described makes sense. Thankfully, it's not ever happened to me, as far as I know....

I agree, though what I think we are talking about here is the resistance to body roll due to the forces of the spring and the compression setting on the dampers.

Again, I think we're talking about the differences between the compression and rebound. Too firm a rebound setting would slow the car's ability to "right" itself after a side or corner of the car has been "loaded" due to weight transfer when cornering and or braking. And that's where the molassas effect comes in, in that the car has not made it's way back to a more neutral or unloaded posture.

I agree, tire pressures play a big role and my driving ability/technique is the biggest and most unpredictable variable in the equation.

The way I've tried to determine this is through trial and error, and alot of tune & testing... Honestly, I don't think we're disagreeing here but probably more than likely we're talking about apples and oranges: compression vs. rebound. I agree that a lighter, stiffer rearend makes for a more oversteer-prone car, but I don't think that you get there by adjusting rebound on the shocks. Ideally, you would accomplish that with stiffer rear springs (e.g., the Real Time ITRs are running something like 1100-1200# rear spring rates, and most successful Honda/Acura autocrossers I know have stiffer springs in the rear relative to the fronts) and by firming up the compression setting on the rear shocks if you've got that option (read: $$$!) Make sense?

btw, good discussion! I can tell you've given this a lot of thought, as have I. Please keep it coming if you think I'm off my rocker.

 

I understand the difference between bump and rebound, and I know that Koni Yellow's adjustment is rebound only.. Single Acting, Single Adjustable shock. What I am talking about is not "righting" the car, I am talking about vertical loads on the tires.

Hmm.. let me try switching the context a little bit, or adding context, or adding a hypothtical example:
Case 1: rebound is "very stiff", bump is "not-stiff"
Setting: Hard Turn
Outside wheel will have a higher steady-state load than it had during straight-forward cruising, inside wheel will have a lighter load. Springs will eventually reach some steady state deflection based on these loads. Outside shock will compress quickly since its setting is "not stiff", and shocks control the rate of deflection, but not the deflection itself. Once it reaches its peak compression (not the maximum compression the shock is capable of, just the maximum point the suspension would go to given the springs, shocks, and input conditions), rebound setting of "very stiff" will quickly kill oscillations. Inside shock will extend slowly since rebound is set to "very stiff". The action of the inside shock more tightly couples body roll to the inside suspension position-- fast body roll requires lifting the inside wheel. (fast body roll being defined as faster than the shock will allow)

Case 2: rebound is "not stiff", bump is " very stiff"
Setting: Hard Turn
Again, there is the same steady state load situation that the system will seek. Outside shock will compress very slowly, more tightly coupling body roll to the outside suspension position-- fast body roll will require the axis of rotation to be the contact point of the outside tire. The inside shock will extend quickly, and once it reaches its maximum extension, oscillations will be damped quickly in the bump portion.

The main difference between the two situations is mainly that Case 2 would tend to "jack up" and Case 1 "jack down". Further it seems that Case 1 transfers vertical forces away from the inside tire quickly and puts it on the outside tire more slowly. While Case 2 puts on it the outside quickly and takes away from inside slowly. As for "righting time" Case 2 will see the outside extend more quickly than the inside compress, while Case 1 will see the inside compress more quickly than the outside extend. An overlystiff system will have "righting time" issues no matter what parameter is too stiff. But even so, the "righting time" issue is a bit of a red-herring..

I'll check out my shock tuning issue of Sports Car, to see if there's a better explanation there, or perhaps more references.

 

Jacking down is a phenomenon that happens with very stiff rebound rates... noteably low/mid speed rebound, as in quick slalom/offset type transitions. This was further developed by Mark Daddio working with Koni.... it does not upset transient response, what they found is that as the car snaked through a slalom/offset, the car would "jack down" , lowering the Cg, and pretty much yielding some awesome transient response characteristics.

-Ryan

 

If we've beaten this horse to death, let me know... I now understand much better the phenomenon of jacking down, thanks to RJ's explanation. It sounds like that, to a point, jacking down can be advantageous. But at the limits of shock travel (compression-wise), it's not a good thing.

Mech, I appreciate your willingness to provide further explanation of your perspective on this, but I'm afraid I'm not fluent enough in suspension physics and geometry (and the terminology derived thereof) to offer any meaningful reply to your last post. And I didn't throw the "righting" issue out there as a deliberate red-herring; it was just my simple-minded way of trying to explain my limited understanding of suspension and handling issues. You certainly have given me cause to pause and re-examine what I believe to be true about shock settings. Now that I think about it, I've been taking most of my learnings on faith from a trusted, experienced and successful road racer (plus some others) who is used to driving cars with Ohlin shocks (double adjustables), without fully understanding all the details of how it all works together. If you can put your hands on that issue of Sports Car and/or other references, I'd be grateful if you would share those citations with me... cause I need to learn exactly what "deflection," "transient response," and "axis of rotation" mean!

 

It can be advantageous... but cars like neons have inherently short suspension travel as it is... something that you have to carefully develop, especially if you're running a national level car...


deflection - the amount the suspension deflects, or deforms under load. This can be due to alot of factors, such as the rubber mounts, bushings, poor camber/toe control under cornering.....

axis of roation - the axis the car rotates around. roughly the polar moment of inertia for the vehicle

transient response - speaking about the response of the shocks/suspension in quick/tight transitions... such as in a slalom. transient as in left/right loading/unloading motions.

 

Hey Neo, that issue was in the May 2001 issue of Sports Car, pages 16-22.. heh.. I didn't remember it, but it even talks about Daddio and him deliberately setting up his suspension to jack down close to the bumpstops..

Anyway, to clarify Type-RJ's explanations I was using "deflection" to more generally mean change in position-- specifically in this case, a change in position that involves the spring/shock combination having to extend or compress (i.e not necessarily involving compliance in bushings, etc.).

And transient or transient response is just a term used to refer to what goes on between two steady state conditions (rough explanation). A certain spring with a spring constant of k will hang a certain steady state distance X down with a force F pulling on it. If you double the force, the steady state length of the spring will be 2X. That is steady state consideration. The transient consideration looks at what happens in the time immediately after you add the extra weight.. there's oscillation and extra displacements involved that steady state says nothing about.

Also, I am not saying that I know anywhere close to everything there is to know about shocks and shock tuning.. The people advising you may very well be considering things I'm not aware of.

 

Mech & RJ, thanks for helping with my shock tuning ed-u-ma-ka-shun. I appreciate the private lessons you've provided here.

That's just my luck. I joined SCCA last June, so I'll have to get the issue from one of my regional Solo II colleagues.

Fair enough. I'll try to pick my buddy's brain to see if I can get a more detailed explanation about the how's and why's of shock tuning. Perhaps that will shed some light on things...

 

I don't know about anyone else but I speak from my own personal experience with my GSR & Koni yellows. I 've auto-xed with the Konis for 2 yrs now and I agree with Neo on soft vs. firm settings.
If I set the Konis too stiff the car behaves horribly on the slalom and it's too slow responding to steering input & quick left-right transitions, etc. thus slowing me down. I cannot point the car quickly enough to where I want to go. Firm settings are a little better for nice long sweepers and faster courses where you want less body roll and a little less suspension travel, but on a tight course with too many fast transitions and slaloms I do a LOT better (2+ secs better on a 40-50sec course) when I set the Konis at less than 1/2 turn up front and 5/8-3/4 turn in the rear. My H&R Sports spring rates are 276F/220R. I also only have a 19mm rear sway with upper & lower tie bars. I fly through the slalom with these relatively "soft" settings. When I stiffen the Konis up it slows me down a lot going through the slalom and the car is nowhere near as agile. It plows more or the tail is just too willing to come around if the rear Konis are too stiff. Totally kills my times. Softer rear settings also help my car rotate much better making the car faster going through 90deg. turns. I 've had the Konis for 2 full seasons ('00 & '01) now and after spending 2/3 of the first season experimenting with many different setting combinations I have found exactly what produces the fastest times for me. Everyone's suspension is different. Spring rates are different, weight of the car, driving habits, etc. You have to play with different settings to see what works best for you. Just remember, being slow in the slalom is what hurts your times the most, and if there are 2 slaloms like there are usually in 2 of the clubs I auto-x at, it could mean a couple of secs delay. I 've found out that being fast through the slaloms with softer settings, even though I may be slightly slower in one sweeper, my times are much faster than if I went up 1/8-1/4 of a turn on the shocks.
People can get technical all they want. I know what works for me and many PROs, national & divisional champs at my club agree with me. It was actually them who hinted that I try softer after they saw me scratching my head and playing with the shocks after every run. I have since been able to adjust my shocks according to the type of course to get best results. It takes time and you must know your car really well. I had to relearn my car all over again when I installed the Konis. It was like driving a different car. It took me almost a whole auto-x season of experimenting until I could get it down. I have also found out that my Konis (don't know about anyone else's) are very sensitive. I can change the car's handling characteristics by just adjusting the **** less than 1/8 of a turn (less than 1 line on the ****), actually 1/16 of a turn will sometimes make a difference in my car. I 'm sure when I get the custom rate GC springs I will have to experiment all over again. Knowing what I know now, it will hopefully take me a lot less than the first time

Harry

 

I guess the ultimate answer is, "Experiment and go with what works for you.." After all, it's all about the what the clock says at the end, isn't it?

 

VTEConly .. good comments. My feeling is that the #1 factor in setting your shocks are determined by what spring rates you have. After you find the range where the shock settings and springs are well matched, then you can tweak for other factors.

I just switched from Pro-Kit/AGX to ERS/Koni .. so we will see how much messing around with the Konis effects handling of the car. With the AGXs there didn't seem to be much difference. Though they only have 4 settings. I set them 3/4f and 4/4r and never messed with them.

 

Ok, what the heck.. let's keep this going as a clearinghouse of rebound adjustment discussion..

I'm a little bit confused.. when you've got the stiffer settings, it can both understeer more and oversteer more? The same setting will cause both?

Just as a clarification, shock settings will not affect the final amount of body roll your car takes in a steady state turn, but it can affect how long it takes to settle to that amount of lean, and how much oscillation you have around it before you reach it.

 

Absolutely! Spring rates do dictate how you setup the Konis. Last year there was this guy with an STS '95 GSR who had GC ERS 450F/400R rates. He had his Konis setup at 1 full turn up front and 1.25-1.5 rear. I would imagine these settings would not work the same on your average ~300F/200R sport springs (prokit, H&R, Neuspeed, etc.) since they are almost half as stiff and most have a 25-30% rate difference front & rear, where that guy's are only 11-12% apart. Camber & toe also play a role and usually demand re-adjustment of the Konis when lowering and raising a car with coilovers. As my car kept settling (went from .75" when springs were new to a drop of 1.3" now - Konis settle too don't forget) the last 2yrs, I found out the Koni settings had to be re-evaluated and reset as well.

 

What, is this national ignore what Casey has to say week?... Sheesh, I said the same thing early on in this conversation, and then things went down hill from there... It's been a good discussion though.

Zsolt, you are absolutely going to LOVE the Koni's. I can't wait to hear from you after you get the chance to run them on the track or at an auto-x. What spring rates are you going to be using with them? BTW, you missed a very fun auto-x on Sunday at Lakewood. It was more like a rally-x given the old asphault surface and how slippery it was. Hope you get your car put back together soon.

 

Sorry James, I 'd love to sit here and explain everything to you but I just don't have the time anymore. But since I used to be like you and question everything I will say briefly that what I meant was: stiff settings: pushes in the slalom (yes like understeer) because when the shocks are too stiff they don't rebound as quickly making the car NOT ready for the next quick transition/cone. This in essense will cause the car to push because it's not responding fast enough to your steering input when you want to go around the next cone and you 'll end up going next to it, missing it, hitting it, or hitting the brakes to make it.. Now stiff settings can have the opposite effect on turns. Even if I 'm on the gas sometimes the tail will come around, where when I soften them on the next run, I 'll fly through the 90deg. turn. When the rear shocks are too stiff, the car back there feels stiff as aboard due to the shocks compressing really slow and that makes the car slide. I don't know if you 've noticed, but the Konis compress slower when set for more firmness. I have pics of my car while I 'm making a hard 120deg. turn and the inside rear wheel is still outside the wheel well (while I 'm 3-wheeling). I also have pics with my shocks soft and the wheel/tire is inside the wheelwell on similar turns - those "soft setting" pics were taken from my fastest runs that day..
I need my shocks to compress fast and rebound fast when I 'm auto-xing. Produces way better times for me. Now it looks like your '00 Integra is stock and that you only have the Konis on since you 're racing in GS in the Philly region. Different animal. Wait till you get springs, sway bars, tie bars, etc. Changes the car all together. Don't forget, shocks mainly help with transitions. If set too firm, you loose that quick transitional advantage & agility that is essential in auto-x, unless you have stiff springs that will oscillate with more power. It may seem your car is handling better but it's not. Now this usually doesn't go for RWD cars. That's a different story.. If you think you can go faster through the slalom with really firm settings on the Konis, so be it.. I fly through it and I 'm on the gas all the time when I set them SOFTer. To each his own.

 

On my stock class ITR, with re-valved KONI yellows (25-50% stiffer), I actually ran full stiff in front and 3/4 turn off of full stiff in rear. This was also with 1/8" toe-out in rear.

 

The setup is looking nice so far. They are 400f/550r on GCs with a GC adjustable 22m rear bar. Right now I have the rears at 1/2 turn FROM full stiff. 550# is pushing the limit of a stock Koni, so I will have less room to play in the rear. I have no idea what I will set the fronts to yet. Maybe 1-1.5 turns?

To be honest, I am not a big fan of messing around with the setup all the time. I will find something that works well on a race track and go with it. Probably won't be the most optimal setting for autox or every race track, but once I can get to the point where the driving is not the biggest variable, then will worry about the gains the can be had from tweaking the shocks, etc.

So I hear. Lakewood Trails Rally-x. I hope to be able to come out for the next one. If not, maybe I can bum a co-drive off some1.

EDIT: Spelling


[Modified by SPiFF, 4:34 PM 2/21/2002]

 

Dave, good to hear how your ITR is setup. Did you mean 3/4 of full firmness in the rear, or 3/4 turn on the ****? What kind of toe and camber did you run up front? Like I said, what works for me may not work for others. The ITR IMO is a much different car than GSR, control arms, bushings, etc. are almost twice the size of GSR's. Then you have the weight difference, various chassis reinforcements not found in the GSR, (in the pilars too..), a more balanced car, etc.

 

All other things aside, another consideration beyond just what spring rate you have is what kind of traction you have. In general, it has been said that a softer suspension setup is better in low traction conditions (rain, poor road surface, hard tires, etc.). Since I haven't had much experience with different tire/road condition combinations on otherwise comparble courses, I can only regurgitate this from others, and not claim it as first hand experience.

I think it's permanently G-Stock for that car... I'm keeping the street manners of the Integra, and I'll develop the RX-7 more towards dedicated performance driving.. (unless I somehow find myself with a chance to pick up a good ECHC CRX or Civic or something)