Shocks or Coilovers?

[akusuma]

I thought some of koni yellows (like for eg/ek) are height adjustable as well by changing the position of the perch

[JohnL]

I thought some of koni yellows (like for eg/ek) are height adjustable as well by changing the position of the perch

Thats what I'm saying, but the range of adjustment isn't all that great with the standard perch (lower spring seat) height options. The perch is located by a clip that fits into your choice of a number of circumferential grooves (three is typical, but some 'Yellows' have more I understand), and the number of grooves can be easily increased by machining extra ones.

I would be cautious just how low you drop though, the standard Konis aren't designed for 'slamming'! For that you need a damper with a shorter body length, or very stiff springs to prevent bottoming out.

[JHMDA9]

Come on, everyone knows what 'coilover' really means, and everyone knows what someone means when they say 'coilover'. The argument is the definition of a moot point so leave it be.

My apologies for stating the 'bleedin obvious'!

LOL I was going to make this point earlier but though better of it, even though there are many people who do not realise the standard suspension is very often a "coilover" setup.
It's just an extra piece of information that people may be interested to know about

[JohnL]

oh, btw, I also have the Konis coupled with H&R Sport springs, which are said to be around 25% stiffer than OEM.

I have standard springs which are of course very soft. If I had the spare cash I’d like to up the rate with new springs about 30% stiffer, which considering the OE softness probably still wouldn’t be all that stiff, but it’s not a racing car! I want to retain standard height (too many bumps around here!), but most easily available and reasonably priced off the shelf up-rated springs seem to be lowering springs in varying degrees of drop. Kmac can do custom spring rates to any ride height for a not unreasonable price, so I might go that way when (if!) finances improve.

As to setting the Koni Sports (yellow) damper stiffness, the stiffer I’ve made them the better I’ve liked it (despite some harshness on some road surfaces), but, I do suspect that what I’m doing here is using the damper setting to make up for insufficient spring stiffness (as some racers do if their class mandates standard springs but leaves damper rate free). Less than ideal I think, but the best I can do at present. I wouldn’t be surprised if, with stiffer springs, I couldn’t back the Konis off somewhat without losing steering response or chassis / suspension control, we’ll see.

I do find (feel) the Konis not stiff enough in the non adjustable bump rate (particularly in the front), though this may again be a function of the low spring rate. I gather that as spring rate is increased that its not uncommon to find that damper bump rate can be decreased (from that required with softer springs for good handling), because the stiffer spring works to increase the rate (speed and degree) with which weight transfer occurs (which I’m currently ‘overusing’ the dampers to achieve). The standard Koni bump rate may be fine with stiffer springs?

Also, a stiffer spring will add resistance to wheel hop after hitting a bump (i.e. further unloading of the contact patch beyond what is directly caused by a bump because of the inertia of the unsprung mass, i.e. inadequately resisted unsprung mass inertia that makes a wheel actually leave the road surface in severe cases), so this might also suggest a softer damper bump stiffness (hopefully the standard Koni bump valving will be near the mark, because I can’t see myself getting them re-valved just to increase bump rate!).

The Konis do assist in limiting body roll, but this is only during swerve type manoeuvres, i.e. the stiff rebound rate slows the body roll to a degree that means if you turn say right then quickly straighten or turn left there is no time for substantial body roll to occur and steering response is good. In long corners (such as roundabouts or similar) where the car spends a long time in a steady state condition the body roll is still excessive and steering response is much worse with building understeer through the turn. Of course damper settings aren’t going to address this, I at least need a thicker rear ARB!

To pinch pennies, I’m considering clamping an additional standard ARB (if I can find one for real cheap!) to the existing one which will of course double rear ARB stiffness (though won’t double total rear anti roll stiffness because the contributions to roll stiffness of the springs and roll centre height will be unaffected). Even doubling the rear ARB stiffness in this way won’t be as much as changing from a standard rear ARB (14mm) to an aftermarket 19mm (Whiteline or Kmac), because the 19mm bars are 2.7 times as stiff as standard (in theory, assuming identical bar shape to standard).

Talking ARBs on Accords (at least CB7 and probably any with the front and rear double wishbone suspension, but maybe others, possibly Civics, Preludes etc too(?)), where the rear ARB linkage attaches to the suspension arm is dodgy (soft and flexible), but can easily be improved. If you have a look at this you’ll see that the linkage attaches to the suspension arm with a short bar that is threaded at each end, essentially a short stud that is thicker in the middle with (at one end) a thinner section that is threaded and fits into the arm, retained with a nut, and at the other end thinner to pass through the linkage bush and threaded on the end to retain the bush / link with another nut.

Problem here is that this attachment ‘stud’ is only supported at the end that is attached to the arm and not supported at the end where the ARB link attaches. This effectively creates a ‘lever arm’ that allows / causes the link end of the ‘stud’ to move up and down as ‘roll force’ is fed into and from the ARB, substantially affecting the total stiffness of the ARB ‘system’.

Its not the stud flexing appreciably, it’s that the plate steel from which the arm is made flexes where the ‘stud’ attaches because the stud ‘levers’ the force from the ARB to the arm. The affect of this unwanted flexure is somewhat similar to having a very soft squashy rubber bush in the ARB linkage, but we can make it more like a hard poly bush!

If you take the suspension arm out of the car (not that hard and relatively quick to do) you can weld a reinforcing ‘strut’ from the lower edge of the arm up to where the ARB link attaches to the stud. This strut must be removable (because of rubber brake line routing) so rather than welding the strut directly to the arm, a steel tab (1/8” or 3mm thick) with an 8mm hole needs to be welded to the bottom of the suspension arm (where the ‘flange’ on the edge of the arm bulges out toward the middle of the car) in such a way that the tab points upward toward the end of the ‘stud’ where the link attaches. The strut can be now bolted to this tab.

Now a short strut needs to be made, I used a short piece of tube flattened at both ends (though you could even use angle iron) and an 8mm hole drilled in each flattened section, one hole allows the strut to be bolted to the new tab and the other allows the stud to pass through the strut.

The strut must attach to the ‘stud’ on the inside of the ARB link bush, sandwiched between the link bush and the shoulder of the stud, i.e. the 8mm section of the stud passes through the 8mm hole in the flattened end of the strut tube and the link then placed in position then the flat washer then the nut. Discard the inner flat washer, the side of the flattened section of the new strut will serve the same purpose as this washer (i.e. to locate the rubber bush laterally). Paint all black and refit and you’re done. Do the other side.

Pay attention to clearance of the new strut to the ARB link, this will dictate exactly where things can be welded on etc. I had a slight clearance problem on one side, fixed by grinding a small section of the link itself. Ensure that when you flatten the tube end that it isn’t flattened equally into the centreline of the tube (as you would get if you squashed the tube end in a vice), but flattened in an offset manner.

To flatten tube ends 'offset': Lay the tube on a flat steel plate and hammer the end flat so that one side of the ‘flat’ is level with the side of the tube. If you don’t flatten the tube end offset like this then you’ll have link clearance issues. Note that it doesn’t have to be a hugely strong installation, the forces involved with the ARB aren’t all that high. Don’t use thick walled tube, 1.6mm wall will be fine, and easier to work with.

This mod made a noticeable improvement to rear roll stiffness on my car, lessening roll and understeer, and a slight improvement in steering response. I’ve also fitted poly ‘D’ bushes to the rear ARB for another slight improvement. The stiffer your ARB the more the standard link arrangement will flex, losing roll stiffness especially in the early stages of roll when the suspension arm will probably start flexing appreciably before the ARB does!

Another place to find excessive flex are the two brackets to which the ARB ‘D’ bushes attach. I’ve taken these out and welded in various reinforcements on them (with noticeable improvement to rear roll stiffness etc), but I couldn’t be bothered explaining exactly how, I’m sure you can figure it out for yourself!