KW+DRC suspension fitted

[voyager162]

as you probably know the actual compression damping is a combination of the rate of damping within the "damper" combined with the spring rate that is effectively trying to stop the damper from compressing, a low poundage spring will give less resistance to the dampers linear movement than say a high poundage spring.
you will see from the above pic that KW use a linear but higher poundage spring, the oem springs are slightly progressive in that their resistance increases with compression.

i am not sure of the spring rates in the KW kit as they dont seem to quote these but from the seat of my pants i'd say its approx 25% increase and completely linear (which is why they include the smaller assistance spring to soften the smaller damper movements.

the ohlins stasis set up is really nice as it has a nice range of adjustment and you gotta love external reservoirs, i use ohlins exclusively on all my bikes and have never had an issue.

http://www.nitron.co.uk/ have some nice kits available and will build you a custom setup for about the same as the ohlins off the shelf solution.

[ArthurPE]

when I think of compression damping I do not consider the initial disturbance/impulse
after the impulse the system compresses and stores energy (in the spring) from an outside force, cars weight and speed vs bump in the road
as it releases this compressed spring energy it extends the shock, this is the rebound
some of this original stored energy is dissipated in the shock, but some remains and over-extends spring (tensioned) and this will propel the system back into a compression mode
this is what I consider to be the compression cycle when damping is concerned, it will absorb some more of the springs energy
hopeful all is absorbed within a few cycles

so the spring absorbs all the energy imparted by the road/wt/speed, and the damper dissapates it over a few cycles by converting mechanical energy into thermal/heat, via squeezing gas/fluid thru orifaces

shock dyno results, typical, up (pos) is compression, down (neg) is rebound
as you can see little resistance for comp, you want the spring to absorb the initial energy, not the car (or the shock)
on rebound you want to dissapate as much as possible, hence much higher rates
comp is usually a fraction of spring rate (if they absorbed a lot of it they would blow on big impacts, the springs are robust/durable
rebound > spring rate, so it 'catches' it quickly

[sonny]

Do you have a pic of the DRC connecting to the KW system?

What psi is the system charged to? Im guessing it was drained when the KWs was fitted.

Iv been running kwv3 now on my rs4 since 2009 an love them, your right you cant beat the external resivours, its a shame the rears dont have them.

[voyager162]

i didnt want to open the can of worms that is the "black art" of suspension movement, having tuned bike and car suspension for over 20years i know how contentious an issue it can become, and could write a page describing the oddity that is static sag and how it totally screws with front to read transition, before we even touch on compression, rebound both high and low speed, oil weights, resevoir pressures, ratio's between sprung/un-sprung mass, damper orifice size etc etc not to mention roll centers, ARB preload tensions and corner weighting. if you throw 100 of the worlds top suspension designers in a room and asked them to come to a consensus you'd be waiting for a long long time.
in its simplistic form the linear movement and acceleration of a sprung/damped wheel is a result of the relationship between the force of the compressed spring and the ease or otherwise of the damper that is holding it, change either damper or spring and you change its P-wave modulus (a complex formula that, at its core describes a relationship between push and pull) i could go into all of this a bit more deeply for the technically interested but for the purposes of simplicity, take it as fixed that fitting higher spring rates changes compression/rebound damping.

sonny,
this kit can be fitted without de-pressurizing the DRC i had a problem with both front struts and the control valve so thought it was probably a good time to get it fitted.
system is filled and pressurized to OEM pressures by the awsome Unit20 guys, i dont know if anyone has tried different fill pressures or switchable restriction valves to fine tune the fluid movement, be an interesting project that.

[Rick_RS4]

how do you remove the drc spring perch from the shock?

[Youngben]

number 1 taps off allowing number 2 to slide off after

[Rick_RS4]

ive got 1 off 2 seems stuck, does it tap upwards and off? hold the shock and hit underneath?

[Youngben]

yes mate its just a good fit plus the crud that has built up over time! perhaps some oil to loosen things

[Youngben]

you need to re use the metal bush that is shown still on the shock in this picture be sure to do this as they can come off with the original spring perch

[Rick_RS4]

brilliant thanks very much for your help,
on the kw spring perch theres 4 holes that are thredded, should these have grub screws in?

[sync24]

finally got this fitted and had a few days adjusting and driving to get an idea of the differences and handling, as no post is complete without pics,

That ride height looks just right - great post!