Mayolives Posted November 7, 2009 Share Posted November 7, 2009 I need advice about how to adjust my Koni 8610 red shock absorbers. Each shock has a small wheel on the top end with holes in it. This wheel can be turned with a small straight tool. I use a very small screw driver or one end of a small allen wrench. The adjuster can be turned about 2 1/2 rotations. According to the adjustment procedure from Koni's site as copied below, that single adjustment knob, as they call it, adjusts both rebound and compression. How can this be? When I adjust the knob in a counter clockwise direction, it definitely softens up the suspension and the opposite happens when I adjust clockwise. It would appear that I am only adjusting the rebound and I would like to adjust both the rebound and the compression. The problem I'm trying to cure is a "chattering" or hopping condition of the whole car when exiting a corner at the limit with the hammer down. These shocks are on my road race car and I'm running 350 and 375 lbs coilover springs, MMS rear adjustable arms, AZC front adjustable arms, Quaife differential with the rest of the alignment set at John Coffee's recommendations. I just don't understand how to set both adjustments with only one adjustment knob. I know that I can read but the instructions are as clear as mud. Any advice from someone with an understanding of how they are to be adjusted or what I can try in order to cure the chattering condition would be greatly appreciated. FROM KONI WEB SITE: Adjustment Procedure 8041, 8042, 8241, 8610, 8641, 8742 Series Rebound Adjustment Procedures Externally Adjustable. These dampers can be adjusted, literally at the turn of a knob, a technique borrowed from Formula-1 racing where KONI dampers have dominated the field for years. One can switch back and forth, in most cases in a matter of seconds, from a comfortable "touring" setting to a more firmer setting for a sporty drive. By means of a knob damping forces can be altered to driving conditions or personal preferences. REBOUND ADJUSTMENT DIRECTION Clockwise = Softer Counter Clockwise = Firmer COMPRESSION ADJUSTMENT DIRECTION Clockwise = Firmer Counter Clockwise = Softer Quote Link to comment Share on other sites More sharing options...
DrSideways Posted November 8, 2009 Share Posted November 8, 2009 Tom, These are the same units I have on my car. They are only externally adjustable for rebound. You can get them re-valved from Koni if you send them in. It would be best if you had them dynoed before so you know where you are at. I set mine mine stiffer bit by bit until it quit bouncing going up the back straight @ VIR. I think I am up to #500 in front and #450 in the rear. My notebook is out at the shop. Been a while since I looked at it. Alan Quote Link to comment Share on other sites More sharing options...
Mayolives Posted November 8, 2009 Author Share Posted November 8, 2009 Alan, Good to hear from you and before I go any farther, the z car crowd misses you and your hot rod at East Coast events. Hopefully you will get it together soon and come out to play with us. I have contacted Koni but they have yet to respond and I suspect they will also tell me these shocks are only externally adjustable for rebound, just like you have stated. However, thats not what I barganed for and what I was told when I purchased them from Ross at Modern Motorsports. Where do you suggest I send them to be checked? You stated that you were at #400 and #450. Are you refering to spring weights? My car is balanced very well having nearly identical corner weights with full load and driver in place. In that condition it weighs 2560 lbs. Are you suggesting that I go up on my spring weights? Thanks again for your help. I know that you have ben there, done that. Quote Link to comment Share on other sites More sharing options...
DrSideways Posted November 8, 2009 Share Posted November 8, 2009 Thanks. Maybe sometime next year I can get back to work on it. No real rush right now though. As for the Koni guys I suggest you get in touch with Lee Grimes @ Koni. He posts here some :http://www.roadraceautox.com/ So you might sign up there and PM him. I don't have an email address for him. I am not sure who locally could dyno a strut insert. Some of the Porsche guys may know. Speedwerks in Thomasville, NC may know of a place. Other than that Koni could. Can't say anything about Ross and his items. However I do normally see two adjustment knobs/screws on double adjustable shocks. I think I am at 500# springs in the front and 450# in the back. I just kept going higher until it felt good and the car would hold ride height going through hog pen. My left rear would touch a bit sometimes with a lighter setup. Not really suggesting you go up, just more of a reference for you. I have the slicks so that makes some difference. When I have to go to radials the process begins again.... @ $1900.00 a set. @%&*#!!! Alan Quote Link to comment Share on other sites More sharing options...
Mayolives Posted November 8, 2009 Author Share Posted November 8, 2009 Adjuster On Top End Ring Tacked On Bottom End For Better Fitment Length Quote Link to comment Share on other sites More sharing options...
johnc Posted November 8, 2009 Share Posted November 8, 2009 (edited) The problem I'm trying to cure is a "chattering" or hopping condition of the whole car when exiting a corner at the limit with the hammer down. The 8610 you have is an older model (haven't seen a red one in 5 years) and the adjustment only affects rebound. It might be time to get those shocks checked out and rebuilt by Koni. I'm assuming the hopping/chattering is happening at the rear of the car. Could be one of a few things (in order of likelyhood): 1. Too much compression damping. 2. Too much rear spring for the Quaife. 3. Suspension bottoming. 4. Driver's side halfshaft bottoming (if R200 in a S30). 5. Suspension binding. Try the following at your next track/test day: 1. Soften the rear adjustment. With the Quaife I think 1 to 1.25 turns off full soft is a good starting point. 2. Swap the springs front to rear if you have at least a 1" front ARB and soften the rear ARB (or disconnect it). With the Quaife the S30 will turn faster lap times with most of the roll stiffness up front and at least a 20% front spring rate bias. Corner entry will be slower but you should be able to get on the gas sooner, way before the apex. Edited November 8, 2009 by johnc Quote Link to comment Share on other sites More sharing options...
jt1 Posted November 8, 2009 Share Posted November 8, 2009 I've ridden in Tom's car, and have felt the "chattering". It's pretty hard to describe, but I'll try to hopefully further the discussion and help him get it fixed. One description is that it's like a 4 wheel drive vehicle when you turn the wheels too sharp and it binds, rocking the whole vehicle. Another might be that of the inside rear wheel going over a series of speed bumps, and none of the other wheels do, but it shakes the entire car. Another might be that the car is rocking on an axis thru the inside front wheel and the outside rear wheel, although most of the movement seems to be in the rear of the car, maybe some going to the outside front. It doesn't do it on entry, but under light throttle midcorner, and heavier throttle off. It 's worse in long sweepers, not as evident in quick, tight corners. When the car chatters, the rear steps out, almost like it's jumping in short steps. The more you're on the gas, the worse it is. Tom's car has plenty of power available, and it can get pretty violent. When you're on the gas harder, the frequency doesn't increase, the amplitude does. We tried a few changes at the track to see what happened. First one was take off the rear sway bar and throw it in the trailer. Tom reported this made no difference he could tell, other than pushing more. Then we went the full range of adjustment on the rear shocks, 1/2 turn at a time, from full stiff to full soft. The chattering wasn't as bad at the soft end, but it was still there. By that time it was getting late and we loaded up, still scratching our heads. John Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 8, 2009 Share Posted November 8, 2009 Sounds like a driveline issue by that description. I'd be looking at taking the Quaife apart and seeing if that is the culprit. Quote Link to comment Share on other sites More sharing options...
DrSideways Posted November 8, 2009 Share Posted November 8, 2009 Does it do it in both directions? Like the left hand turn 3 @ VIR. Or the right carousel @ CMP? This could cut the half shaft out of the possibilities? Has it done this since built? Or is it something that came with developement? Alan Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 8, 2009 Share Posted November 8, 2009 I believe Tom is running 300ZXT CV's. I think that makes it less likely that the halfshaft is the culprit, but it wouldn't be a bad idea to pull it apart and check for problems too. Could also be a CV bottoming issue as John suggested, but I seem to remember Tom went to some length to have the CV shafts shortened to prevent that problem. I don't remember him saying whether he ran it through the travel by hand to feel for a bind though... Quote Link to comment Share on other sites More sharing options...
Mayolives Posted November 9, 2009 Author Share Posted November 9, 2009 Does it do it in both directions? Like the left hand turn 3 @ VIR. Or the right carousel @ CMP? This could cut the half shaft out of the possibilities? Has it done this since built? Or is it something that came with developement? Alan, The car reacts the same in both directions. I'm not sure when the problem showed up. It has probably been there since day one but only in the past year or so have I learned to drive it at the limit and be able to understand and be able to better describe what is taking place. JMortenson, I've been watching and listining very closely and there is no evedence of the suspension bottoming out. The stub axles are custom shafts with 930 P car ends. The don't touch anything through their full range of motion. Quote Link to comment Share on other sites More sharing options...
DrSideways Posted November 9, 2009 Share Posted November 9, 2009 This is sounding rather peculiar. On one hand it makes it tough to isolate. On the other it raises the chances that when you do find it, it will be simple. Have you checked the drive shaft? Most everything on our cars is solid mounted. A problem there could show up in high torque, high load conditions. Another area you should check is the inner rear control arm bushings. Play up and down or fore/aft can be tough to isolate and cause all kinds of racket/ vibration. Front differential mount moving? The shock insert is being fully clamped in the tube? Insert nut in camber plate clamping to strut instead of spacer? Alan Quote Link to comment Share on other sites More sharing options...
johnc Posted November 9, 2009 Share Posted November 9, 2009 When did the chattering start? Being more prominent in long sweeping corners is when the rear suspension is full compressed and extended. Some ideas: As mentioned above, could a CV be at its angular limit binding slightly at full droop or full compression? Take the springs off the car and check how the CV feels while spinning it at the limits of suspension motion. Could a CV be pulling out of the diff (popping the snap ring) and then popping back in as the car straightens out? Pull both CVs and check for chewed up splines. A Quaife diff will make a growling noise when the inside rear is at the lower traction limit. Usually you hear the growling and then the inside rear breaks traction and spins. I had the R180 with the Quaife in my car do something similar to a chatter but dropping compression damping and rebound on my shocks eliminated that - I was picking up an inside rear in certain corners. Quote Link to comment Share on other sites More sharing options...
mark Posted November 9, 2009 Share Posted November 9, 2009 Dead strut insert? Have you had the rear apart to check? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 9, 2009 Share Posted November 9, 2009 930 CV's have a pretty high angular allowance, I'm doubting it's binding due to angle. I'm still thinking the CV shaft is topping or bottoming, or the Quaife is doing something funky. I just can't see what has been described as a shock issue. It's a good mystery though! Quote Link to comment Share on other sites More sharing options...
johnc Posted November 9, 2009 Share Posted November 9, 2009 Dead strut insert? If its a dead shock, we're all wasting our immense analytical skills... Actually, if its a dead shock, we all get to kick Tom in the butt the next time any of us see him... Quote Link to comment Share on other sites More sharing options...
jt1 Posted November 9, 2009 Share Posted November 9, 2009 we all get to kick Tom in the butt the next time any of us see him... Best idea I've seen so far. I will monitor this situation closely!!!!!!!!! John Quote Link to comment Share on other sites More sharing options...
Mayolives Posted November 11, 2009 Author Share Posted November 11, 2009 I have received some good information from those who have responded to this thread and from others whom I have contacted. Koni technical gurus have informed me that the 8610 dampers are only adjustable for rebound. Now I have a number of items to physically check on the car but I suspect the Koni dampers are not the culprit that is causing my problem. They all appear to be in good working condition but I have shipped them to Koni to be dynoed. My search is now centered on the suspension components and where they are mounted, the ends of the axles where the go into the differential to see if they may be moving in and out as John C mentioned, binding issues, weather or not the parts are bottoming out, rear toe alignment and lastly, checking the Quaife to see if there could be issues causing it to load and unload improperly. The search is on and I'll share my results as they present themselves. Quote Link to comment Share on other sites More sharing options...
DrSideways Posted November 12, 2009 Share Posted November 12, 2009 I may have missed this but.... is there any noise associated with this issue? Alan Quote Link to comment Share on other sites More sharing options...
johnc Posted November 12, 2009 Share Posted November 12, 2009 is there any noise associated with this issue? Shouts of "Oh Shiit!"? Quote Link to comment Share on other sites More sharing options...
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