captain_pants

The word 'preload' should be banned from suspension discussions. Your spring perches set the ride height of the car with your given springs. You shouldn't give a darn if they're compressed 1" or flopping around at full droop, the goal is to set ride height and adjust corner weights. I care about my car's performance while at ride height, not when all four wheels are hanging while on jackstands. However, you may want to use helpers/take-up springs to keep the springs straight on the shocks when airborne and/or jacked up.

I like to use the helpers on the bottom, think of driving over very high frequency bumps: The wheel is bouncing up and down very quickly - if the helper is on the top it would have to accelerate the heavy spring down very quickly to keep it in contact with the lower perch. On the bottom, the main spring stays planted against the upper perch and the helper accelerates only a portion of it's own weight to stay in contact with the lower perch. The fact that different companies do it differently means it doesn't really matter much either way.

The stock bushings also help to keep the main springs in contact if they were tightened at ride height. My rear suspension compressed over an inch after removing the shock/spring while on jackstands just due to the bushings pulling the hub up.

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My setup:
Penske 8300s, 750F/500R springs, stock top hats. Lengths were picked to exactly match the stock point of bumpstop contact (from when I was in BS), though I don't have that info handy right now. The current valving sucks so I'm shopping around for rebuild options. It seems as though everyone I speak with says some variation of "Trust me, I have the best valving." That makes me uncomfortable...

Random1

The word "pre-load" is valid for the discussion, but most of us do not use shocks that have a pre-load capability. Teins are the shocks that come to mind as well as many JDM shocks in general. With the models that do have a pre-load capability there are two adjustments. One for pre-loading the spring that is just like the perches we all know and love; the second is a shock length adjuster that allows the ride hide to be adjusted.

The photo below of Tein Flex shocks clearly shows the two adjustments.

murderedrsx

I haz those. Granted I really don't see the point in preloading the springs unless the car is "dumped", effectively moving toward the most rate. Anyway mine are set with 0 preload nut it is nice to adjust the ride height by just lengthening the body of the shock.

captain_pants

Anything that changes the height between the lower control arm mounting point and the spring perch will adjust ride height. Changing the body length of the shock will change when the bumpstop engages and the droop height - as well as ride height if the spring perch isn't also adjusted accordingly. I'd set those parameters as I want (usually so the bumpstop prevents the tire from hitting the body, droop is highly car dependent) and then adjust ride height to suit.

Typically this style of arrangement sacrifices total travel so you've got to pick which one you want. The rear shocks in the S2000 have very little room to accommodate lots of droop and a reasonable bumpstop engagement, the big thread-on lower perch will likely sacrifice one or the other.

H22A_CD5

From my (basic) understanding, preload only makes a difference in springs with a progressive rate. This would make them have less of their soft travel and more toward their stiff travel. Springs with a linear rate would make no difference except raising the car at the perch creates more travel/less droop and vice versa. I like the idea of being able to adjust ride height by lengthening/shortening the shock body, this allows you to control how much droop you have (to combat inside rear spin) or travel you need (incase you're low enough to ride the bump stops) independly from the ride height. But it seems only the lower end of the suspension spectrum come set up like this. I wonder why that is? To me it makes more sense, for the above stated reasons, but I guess suspension companies dont feel the same way on that one. Perhaps the threading of the shock body forces them to run a thicker body or risk weakening it (I'm really just guessing). Maybe some of you gurus can chime in on that one.

mLeach

I just wanted to add to this thread that I have been running a set of revalved Koni Yellows on my car and have been very very happy with the results. The range of adjustment is huge, and it is very easy to change the balance of the car using rebound adjustments.

That said, the thing I think you leave on the table with this shock is your ability to get to maximum grip as quickly as possible, on the range of surface conditions that one might see in an autox. Having driven on a number of external resevoir, compression adjustable, large piston shocks, I can tell you that low speed compression can be really great when making adjustments mid corner, because you transfer the total weight across the axle at an earlier phase of the corner. The only way to do that with the koni is with a larger sway bar, or with more spring. And even then, the rate of change of weight transfer is still not quite the same.

Acknowledging all of that, I have no plans to upgrade to a high-end shock. I will likely go up in spring rate to try to find a little better chassis control, but think that these shocks are more than adequate for 99% of the autoxers out there - They could be shorter in the rear, but oh well.

bits on the car:
konis - race valve
850/700
gendron solid on 6/6
-3.2 camber/zero toe front
-2.6 camber/.25 toe rear
mx5 bar rear
chopped exhaust
255 rs3 on 9" wheel

josh7owens

Can anyone tell me why I don't like much compression? It seems like everytime I turn up the compression the car feels nervous, and seems to let go faster. I run "some" compression in the front like 2/5 on low speed, and 4/14 on high speed but anytime I try to add any to the rear, the car gets really loose.

oinojo

too much compression force. what are your canister pressures at/set?

josh7owens

I think 150 maybe? Is it bad I'm not sure off the top of my head. HaHa

The fronts are at 2/5 low speed, 4/14 high speed.

this graph is at 2/5 low speed, 8/14 high speed


The rear is loose because of my toe setting to start with but I can't turn it up past 0/5 low speed and 4/14 high speed with out it feeling very nervious.


ps- rebound is at 12/14 front and 10/14 rear. 900f/700r springs. Rebound is set at 65% critical.

Random1

Added poll questions for spring rates. If you voted on the shocks prior then you will need to delete your vote and re-vote for all questions.

In this poll for some reason you can click on "view" next to any poll answer and see who voted. Does anyone know if there is an option for this? I don't see "view" available on other polls?