Got the koni struts recently

Wondering if I would be harming the new struts if I installed them and waited for a few months to install the new front springs? Due to the fact that I want to replace the a arm bushings when I replace the springs ... More potential complications that I am not ready for - yet..

Also, noticed that the struts came with a **** to adjust the firmness, it shows tuning counter-clockwise makes the ride "stiffer" but for what I understand the rear shocks need to be turned clockwise for a "stiffer" tide, I.e. the "0" setting is completely counter clockwise and full soft. Am I mixed up on this ?


Shouldn't the rear shocks and front struts have the same adjustment procedure?

 

My front springs are very old..probably the originals

 

No, your old springs will not damage the new struts. Your springs do not lose their spring rate over time.

As far as the shock settings, they differ for all vehicles depending on variables such as spring rate, sway bars etc etc. Koni recommends to start out at the softest and gradually increase from there until you reach what you think feels right. I think it's funny when people seem to have the perfect prescription for all cars and recommend x number of clicks front and rear. There are many things that can affect what is optimal, not to mention, it's really about what the driver thinks feels right.

Hope that helps

 

http://www.koni-na.com/adjustment.cfm Look at figure 4 to see how the rears are adjusted. Yes, you are correct. Clockwise = firmer (more "clicks")

The front struts have the **** adjustments. All you need to do is remove the stock dust caps off your strut mount with a small flat head screw driver. Put the **** on and adjust to where you want it. If you have aftermarket strut mounts, the adjustment piece will be already be visible (dust caps don't fit on the aftermarket strut mounts).

I did front struts, then waited several months before doing front springs and Del-Alum A-arm bushings.

You have two options for rear shocks:

• 3rd gen shocks - These are the "off car adjustable" ones with the click settings.
• 4th gen shocks - These are the "on car adjustable" ones with **** adjustment (like the front struts) You'd adjust these from your back seat behind the carpet.

The 4th gen rears are about $100 more expensive. But I've never adjusted the rears anyways. Your choice.

Don't forget that if you're planning on doing aftermarket strut mounts in the future, do NOT reinstall the stock strut shaft boot that mounts on top of the strut before reinstalling. The aftermarket strut mounts don't work with them. Some members report success with the accordion style that come on off road trucks. Most people use none.

 

I haven't confirmed a successful install of a fourth-gen rear shocks being installed and allowing access for adjustment. I would confirm this before buying them.

Also, the rear shocks are usually good-to-go at setting 1 and people usually never touch them again. haha I would save yourself the $100.

- Kevin

 

The 4th gen rears adjust with a ****, you will have to pull up the carpet and remove those foam insulator thingies tucked in there to get access and puit the white **** on to turn.

 

I would adjust mine often based on what I was doing. Im not the "most people" though and understand how to use shock damper adjustment to my advantage. I would never buy shocks or struts for a sportscar that were not adjustable, otherwise you are missing out on making the car optimum for the intended use- this is always changing based on weather, conditions, weights(including driver/passenger weight changes), tire changes in size or change just tire strutcture quality with a different brand or series, future alterations or modifications to the chassis or suspension, fuel loads, etc

I do not skimp on shocks, nor tires. I spend al my money their first because with these in top quality? everything else you do is pointless in lap times and safety when it comes to grip and chassis weight control as well as ride quality.

Around town I was always 1 turn down form the high position on the fronts and 1 in the rear (out of 0,1,2, and 3 position) for the grocery getter-

Half a turn for top on fronts and click 2 on rears for street use if I was in it by myself all day without the family (I rarely drove that car- it was for the ex)-

then I would max the rebounds front and rear on 3 for short track use(autoX type stuff, and max front & 2 rear for long track long braking zone use.

Just a few FYI examples of general changed settings for that car. I did have 825 lb front springs on it with a lightweight V6 front chassis so the heavy springs would have alot of recoil force that needed slowing. Full rebound on bumpy street roads would generally yeild front tire skipping laterally over bumps. I would run rfull rebound on smooth surfaces without drainage type dips inthe road or raise manhole cover type bumps- tracks are generally a lottle smoother so no skipping on courses that lack water runoff features of street roads.

 

Dean, how come you went for the 3rd gen rear shocks instead of the 4th gen rears? You're the type of person who would have benefited the most from the on car adjustable rear shocks.

 

I personally chose third gen version because they are monotube design and the 4th gens are twin tube. Deans answer may vary. Check out this video below on differences between the two. While the 4th gens sound cool because they are double adjustable, the monotube vs twin tube is where the performance difference exists

http://www.kyb.com/parts/monotube.php

 

I have no fancy reason. I really have a simple reason. It is the standard Koni yellow rear shock that the Koni expert engineers designed and valved for 3rd gens. At the time I bought it, I new nothing about any difference in shock adjustment design of the 4th gen, but I did know back then the 4th gen was/is a heavier car.

also, when I bought the shockstrut combo, I had no idea that the struts were twin tube and not monotube. I thought all performace Koni's were monotube since that is all I had for years from them.

My father had Koni's on my race vette as far back as I can remeber when I was a kid holding the flashlight for him- he bought the car new in 1968 and I still have it today. I grew up with Koni shocks and have learned to trust them.

Also Reid, as you knwo the rears I had were adjustable, Id have to drop the bottom bolt off the mount to do so but was not really an issue.

 

Well I'm not Dean. However if you have to pull the carpet up every time you want to adjust, then I say the third gen style is easier to adjust. You could put a small slit in the carpet, but that is not my style. The third gens only take a few minutes to adjust.

 

Im glad your name is not Jimmy either, arh arh.

As John and I both stated, its not that difficult. You are not turning them that much or that often. maybe when you first get them but you still should put some miles on the car on each setting to see how the car reachs. Get to know the car. No car will be fast out of the box- unless you are downright lucky (being good has nothing to do with it.)

For racing- you pretty much do not want the rears to skip over the pavement. Spring rates have alot to do with rebound rates- they go hand in hand because the stiffer the rate of spring combined with how much the spring compresses (via body weight and/or wheel assembly weight),. that compressed energy will recoil. The more the energy the more the recoil- so thus- the more rebound shock damper needed. Too much rebound on a weaker rate spring will cause the wheel not to want to return down as quickly over a bump and the tire will skip over the pavement without enough pressure applied for grip.

bad suspension geometry in the rear will cause brake hop. Just like LCA's will cuase axle hop if the LCA is inverted, the LCA angle eingthe opposite way will cause brake hop- especially if a shorter Tqarm is used. You want the LCA about level withthe chassis pulling straight on the axle under rear brake conditions. If the axle is lower, and the shock compression damper is low, the axle will hop under braking force as it bites then skips then bites then skips across the ground like a basketball.

Uping rear spring rates only cause the axle to want to release more under hard braking (rear jacking effect) hence why a stiff spring is actually bad news instead of good. You want to control the upward thrust of the axle which is the compression stroke, but not create jacking and have a raised rear of the car with a bad LCA geometry. Remeber that springs want to release energy so as the rear lightens, the springs release and the car raises.

Everyone starting to see why I ran very heavy increase "prgressive rate springs" on the rear of my car with ggod Koni yellow compression valving? I could also get away with heavy click #3 rebound vavling and not skip tires under braking in slower (shorter distance) speed braking ziones like in autoX, On the larger high speed brake zones(longer distance braking zones) I hade to run click #2 becuase the car would have longer time to release energy and lighten the rear tires enough through body movement that the tires would sometimes skip at the end of the braking zone and lockup. THis is the jacking effect cause by too much rebound on any wheel. TOo much rebound will not allow a wheel to release back down so each consequent bump will cause the suspeension to compress more and more until it grounds out. The rear of these cars are notorious for jacking under braking and eventuall do the opposite effect of compression jacking in longer brake zones. Progressive rear springs help reduce this, but will still not eliminate it.

We have not dive/antidive setting buit into the fronts of these cars (well we kindof do but its by accident and you have to know how to use it) like how double wishbone front suspensions have. THis keeps the nose of the car from divng which will tansfer weight over the nose from the rear of the car.
The higher the nose of a 3rd gen, the more the rear jacking effect will take place. Most thrid gens can not run low without rubbing. As we all know I also had a very light weight noses V6 car with also very light weight wheel assemblies/brakes that would not thrust into the fenders over bumps with the ride height that low. What am I getting at? the anitdive. However, its not really anitdive as better named "antilift of the rear via front geometry leverage" to make that sound silly. The strut length!!!!. The overall length of the strut from spindle center of the wheel-to- the top strut bolt distance. THis is the angle (caster will decrease leverage) as well as shorter length (like a breaker bar) will also decrease leverage of the rear off the car lifting. Most cars can not reduce this static length. Dynamic length is most people problem (or suspension travel) the heavier cars have to start at a higher static length and travel more under dynamic lentgh which also makes for a lower front roll center= bad.

More reasons my car worked so well. You can see how many things effect a choice of part and setting that part.

 

From what I gather, monotube is better than twin tube.. They gave the 3rd gens better shocks! lol nice

 

Very interesting...I'll have to re-read your post a few times to soak up what I missed the first time.

I'll admit that I never considered higher spring rates being a factor is making the back of the car pop up during braking. I always thought about springs just for cornering and average driving.

It sounds like there is a happy medium somewhere in the middle when it comes to bumpy roads at high speeds. There is a highway loop that I drive on the way home from work. Going from the south part of the loop to the west part of the loop, you get a sweeping corner to the right. Taking it at 75-80 mph with the front/rear on full soft, I get body roll in the wrong direction. Adjusting my fronts to 1 full turn, the car feels better going through the corner. The trouble is that the road is not smooth. There are tiny ruts that make the possibility of the car "hopping" if I enter the corner too hard. The delsphere PHB helps in that regard to keeping the rear end from hopping when it shouldn't. But it also sounds like if I had the rear set for 2-3 clicks instead of 0, that I might be in trouble.

I had wondered why you ran the progressive springs.....Sounds like a slow motion way of controlling the jacking effect.

Last week when I cranked the front Konis to max rebound settings (for no other reason than something to do), I found the car actually felt less in-control than it does at 1 full turn. It felt like the suspension was locked. But it made the tires feel more wobbly. Like any motion was happening below the car instead of in the suspension area. I didn't like it......Made for fun city driving at speeds below 40 mph though. I took it fairly easy driving that night as I figured the full firm front end with 0 clicks on the back end is a recipe for uncontrolled surprises.

 

Dean wrote: "With the softer extended progressive spring rate on the inside corner wheel, the weight transfer and thus increase of wheel rate (and here's the kicker) migrates the roll center off center chassis laterally to the outsde wheel very rapidly-"..."THe porgessive rate spring release pressure is not as great as a linear springs so this aided but the swaybar connecting both sides and the hi rebound helped prevent wheel hop. You can pretty much only get away with this with a lightweight nosed V6 car. THe V8's will still wheelhop and/or be very very loose under brake crnering becuase of the heavier nose weight of the V8 rolling the nose and lifting the insider ear of the chassis still."
post #54
https://www.thirdgen.org/forums/susp...ignment-2.html

 

That quote is dealing with a low to mild speed corner entry and about how the rebound holds the inside rear of the chassis down- and consequently keeps the LCA angle good- no diagonal jacking of the inside rear under brake-cornering. I focused on keeping the inside rear LCA as paralell as possible while the outside one would invert and pul the axle forward causing roll induced understeer in mid corner squat. In corner entry braking, the LCA's would not have long enough straightline braking time to release to a bad angle where compression damper was relied on to hold wheelhop.

The comment I made on THIS post about compression holds the wheel from brake hopping pertains to a long stright braking zone that wheel hop would traditionally happen about mid brake zone long before the corner entry comes up. THe difference is in one situation the car has the yawed roll center leveraging the inside rear as the outside rear is squat induced from cornering load, the other senerio has only rear jacking effect where both sides are lifting so no swaybar to pull one down with the other (and no diagonal leverage or teeter-totter). One the Rebound comes into play, the other relies on compression valving to help reduce straight lne wheelhop as a result of jacking the whole rear.

These are both very complex visuals since multiple things are going on different in each case.

Reid, the suspension was being held down too much witht he high rebound and the car was boucing off the second and thrid multiple series of bumps in compression stroke rather than a bump per stroke (It's technically called "the jacking down effect of a shock"). THis shock loads the tire sidewall vecuase the car is jacking down on the suspension and increasing the wheel rates as it does- which makes for the tires having to absorb and release more energy on the sidewall- that is undampered energy and will gie an uneasy feeling.

 

OK, Professor Sake', we can talk of both scenarios separately but they are inter-related. There is no free lunch.
Lowering does help both, however. And will lowering the axle attachment of the PHB will effect this scenario (sway bar no effect)? If the springs are progressive, how much spring travel is needed to get into the heavier progression? If the shock piston stroke is reduced by lowering, how does one ensure that the compression valving is getting into that progressive zone and matching it where one wants it? Are there any metrics or starting points?

 

They are related in parts, but not in optimum settings. WIth anything, there has to be a happy medium and a give take as to what setting make which feature more important. This is why I change the rear rebound setting for the higher speed (longer braking zone) use. When slower autoX type racing uise is desired, I favor more for cornering rebound because brake jacking is not an issue. The rear rc lowering (through PHB setting) does effect how the chassis rolls both laterally AND diagonally. Too much lower and it increases lateral leverage as well as diagonal leverage. This is why I barely lowered the rear RC, and barely raise the front RC front eht lowered R postion for suspension loiwering geometry (I hope you got that..lol- the front rc goes low faster than the front cg, so you have to reraise the rollcenter in front with extended ball joints to bring it back closer to both the fore/aft center of gravity, AS WELL AS the later center of gravity. Now think of the diagonal weight transfer from lets say LR tire toward RF tire. Tink how the roll axis as well as the yawed rear rc help trestrict the diagonal transfer in both weight leverage as a higher teeter totter point. (also less nose weight of the V6)

First off- you are comfusing a 2 step linear spring (2 different linear winds in one spring) with a progressive rate spring that has an continuing increasing rate with each wind. The 2 step spring requires coilbind of the first lighter step- I did not have this type. My spring compressed from the top down and "progresively increased spring rate very smoothly- no abrupt bump in quick rate increase. Once the rate built a little into almost and inch compression, the bumpstop would help up it a a little quicker rate as not to ground out. WIth any solid race suspension, big bumps are not your friend so yes it would glance over large bumps when very heavy impact would ram the wheel upward on a set corner- but also remeber the yaw in the rear roll center jammed outward just as quick to leverage the inside wheel form lifting and rolling the car- any outside rear tire the tire would take most of the inpact at that point, and the split second airborn over the bump gave time for the larger sidewall tire to recoil in form so you really never felt it. Its all about getting the tire and suspension frequencies to match for good ride quality- that is why I like a stiffer suspension and a more forgiving tire.albeit the tire sidewall still needs to be very good quality not wallow everywhere on impact. Just absorb and go back to form without too much unwanted bobble. Again- this is where a low profile tire will shockload the sdewall and cause all kinds of twitchiness unless its very wide footprint to aid in absorbsion.Remember also that I could run the massive 25mm swaybar ( because of the lighter weight smaller engine car)so it linked the rears left and right together closer to reduce rear chasiss roll. By the time the car got over the bump, both the swaybar and the tire would be returning together and that frequency worked where it was ready for grip agin with the heavy rebound shock setting (you need very good quality shock dampering for this- the only one on the market good enough in rebound force and quality is the Koni Yellow. On a quick impact, the swaybar has greater deflection speed than just in corner roll. so it will still move a little bit more independant that just lateral roll force when one wheel hits a bump (not a dip though) so it works in deflection and recoil on tire lift, but more mildly together on chassis roll leverage.
I am forgetting that car since I have not had it in 5 years now. I remember the front travel (with pictures) to be set at 1" normal suspension travel and a max travel ever of 1 1/2". The rears took over a year and many take aparts to finally get it right. I had shaved the original bumpstops down quite a bit or they would hit under normal driving (also hammered the TqArm tunnel clearance under the rear seat area for greater clearance- it actually split the sheetmetal and then I plated it with thin guage from up top with a few spotwelds and epoxy.) I think the rear traveled about 7/8" if I recall- I have it documented on here somewhere in archive threads- it would then hit the Koni progressive 'shaft style" bump stops that started with like a 30lb rate and went up about 100 lbs in about 1 1/4" more travel. I designed it to ride onthe special bumpstops purposely where it sat in outside corner set. I did this with rubber Oring testing on the rear shock and skidpad work to see where the suspension compressed when set into a corner load a full lateral speed of the skidpad without sliding (max body roll. Also take into account I ran 50 series tires (factory 245/50-16's) to keep some sidewall on the car. I have never been a fan of low profile tires- they cause alot of handling twitches. The progressive rear springs I cut some of the lighter side of the coil. THe side the top side that starts with lighter rate close winds and progressively increases wind gap with every coil.

Then in video reveiws of the insiderear fender gap, I could estimate that the inside rear LCA was going form inverted to almost parallel on geometry to lengthen in effect and cause the rear axle steer(as the outside LCA pulled the axle forward in corner squat.

The release rate of the progressive spring brought it higher (26.5") slightly that static height (26")in corner roll. I also had the LCA's as short as possible in length shortening my wheelbase by a little over 5/8" and stuffing the driveshaft yoke into the tailshaft as much possible without grounding out. It was a real bitch to get that driveshaft out, I had to lengthen the LCAs to do so. The custom Ipipe muffler sat lower under it also so it made real hard to drop the 4" round Carbon Fiber driveshaft, but it was well protected up under there from anything hitting it from the side and brooming it into strings (built in safety factor on a CF driveshaft, you do not need a safety loop with them)

Koni builds the 3rd gen rear shocks for expected lowering. They are a little shorter and designed for that- same with most all other aftermarket shocks for these cars. There is enough range of up and down so as not to get towards the end of either stroke.

Starting points? It took along time and alot of testing to get this car like I had it. I spent weeks on end with it when you count all the individual hours I tweaked and changed parts- starting with I use three different sets of coils oiver the years learning it. The first tw sets were all linear- and I could not get rid of the rear jacking. I figured when a porgresive rate spring compresses, it gives the higher cornering rate I nned, and when it releases it will not thrust the chassis upward as much as a linear would under long distance high speed braking- and it worked. It also leveraged the roll center to the outside which as stated, it weighted the inside rear wheel better which is hard to do.

 

More important info on this. It is important to realise the working dynamics of a swaybar- mainly how and what it is hooked to.

Under chassis roll, the swaybar is weighted by the heavy chassis, which will lean more predictably and smoothly because of the massive weight upon the swaybar. thus the chassis weight is far greater than the wheel assembly weight and will bring the inside wheel upward with it and not allow the spring to push the car over in roll. However- diagonal weight overt the front, as well as roll axis diagonal transfer will unload even a heavier rate spring from pushing the tire to the ground for grip. If you do not have the chassis weight on it, a larger spring will only diagonally roll the car more than a sofeter spring that has more chassis weight. The overall heel weight might be the same, but the footprint fron the chassis roll will differ adn be more favorable in the lighter spring /less body roll senerio.

Back to the swaybar again- we talked about body roll and chassis weight effects- it keep tboth tires closer to equal suspension travel at al times under roll on flat ground- with that said, lets lok at the reverse effect of the swaybar. When a chassis remains flat under striaght line travel, but one wheel hits a bump, the swaybar is yanked up on that side. Does it pull up the other side? Not as much as it would pull down in chassis roll in a corner- probably about half or less....Why? because the bar is a coil spring and bends under abrupt force just like a coilspring compresses and releases. It is not rigid. When it bends, to transfer that upward force across to the other side to lift the other tire up to the chassis does not work the same becasue it is trying to yank up the wheight of the wheel assembly (brakes and suspension included) as well as forcing against the other wheels coil spring rate. THe swaybar will more quickly yank the bump wheel back down rather than force the other "non-bump" wheel upward off the ground.

Professor Sake' (as in Japanesse alcohol- not pronouced like for pete "sake") in a nickname all the locals call me- its a long story I will not share here. I figured Id put up some pics to put the name with a face. Alotof you have known me on here for years but really have no idea what I look like. I was talking with someone local the other day about how when you get to know someone you actually llok at them differently then when you make up your own visual of who you think they are- its like seeing a talk radio host for the first time after listening to him/her for years. My experience is its never who I had imagined (not good or bad- just different) people are generally friendlier when they feel they know you a little.

Dean

 

damm i feel like im back in school reading some of dean post.. i printed some of the threads to study when im at work

 

I am at work reading this and my brain hurts .. Dean why are you doing this to us lol

 

I'll re-post this diagram. He calls the Roll Moment as the difference between RC and CG (Center of Gravity - or his Mass Concentration?). I can see why in the front raising the RC closer to CG is good. Can you ever remain equal distance RC to CG front to back? or equal Roll Moments front to back? Obviously, there is going to be a rake front to back.
A shorter rear Roll Moment would aid the sway bar, correct? or is it just a weight consideration with the bar? Lower rear RC must help the brake jack effect, but then also lowering CG is more difficult.
I was going to say, Dr. Fermentation, but I don't know your sense of humor (most Profs have PhD's).

 

First off- Mamba- you are always in school when you come over here. Ill see you next week young grasshopper when we finish your exhaust. My brother has a drill press we can probably fab your STB mounts better with. Ill see if I can borrow that and throw in in my truck next time Im there.

I have fermentation in my underwear- thats a visual you all wanted

Now to the topic in hand- Brian, I do not agree with that Centroid axis (as you know I have stated in a past conversation). Why? becasue the Cg and 'both' the rc's are always changing distance from eachother in 3 dimension. There is no such mass centroid axis in vehicle movement so I do not see its relevance- Shelby was over thinking that one (May he rest in peace).

You could set that distance equal in static form, buit it would change the second someone rested their arm on lets say the front left fender, or you ate a big lunch, etc...if you get my drift. Dynamic motion is always changing that moment distance in 3D

edit:... and I happen to have a great sense of humor....just f#%king ask me

 

All you gotta do when looking at a part is figure which way it is being pushed, pulled tugged, yanked, spun etc. When you see how and why forces are applied to a particular part, you will start to understand how to resist it, or magnify, or supress it, whatever you need to do. Everything is attached to something, does that something it is attached to weight more than "it" does? or does "it" flex more so it does not move- etc. etc. I will somethimes take a wheel off and then sit there on my little roll around stool just starting at different suspension parts brainstorming what I can come up with next.