Subject: Re: [s-cars] Correct Bilstein / Eibach Suspension
Availab ilit y
LL - NY
larrycleung at gmail.com
Sat May 21 19:42:52 EDT 2005
Whoops, your friend is correct. Rebound is the damping effect that is
caused when the shock is extended (wheel drop). Jounce is the damping
effect when the spring is compressed. Double adjustable shocks adjust
both, the good ones separately (meaning two separately adjustable
valves) such as Ohlins and Penskes. Tokico Illumina's adjust both but
simultaneously, and Koni's only on rebound. It's been awhile, since
I've looked seriously looked at this, sorry for my mistake on the
LL - NY
On 5/21/05, lebakken1 at netzero.com <lebakken1 at netzero.com> wrote:
> A good friend of mine is a Porsche/Audi mechanic, a racer, and he also sets up alot of the Microsofties play cars here. He tells me that the Koni adjustment is in REBOUND.
> What is "jounce"?
> -- LL - NY <larrycleung at gmail.com> wrote:
> Responding off list 'cuz this is long.
> The rankings, in order of stiffness, to the best of my recollection are:
> (would be best to check the archives, the first 4 were recently (this spring)
> tested by a lister on a spring tester, and the lister doing the work correctly
> isolated the dead coils in the springs)
> S6, post '92 S4
> '92 S4
> Eibach ProKit (and just barely more the the '92's, just lower by about 20 mm)
> H&R UrS (not sure how much lower, but it's supposed be similar to the Eibach)
> not tested by the lister but, stiffer still:
> H&R S6+ (meant for the Euro S6+ with the 4.2 V8)
> There are other availible springs (Spax, for example) but not tested.
> Spax lower the car to the floor, IMHO, too far.
> Now with shocks, as Taka noted (and I've experienced his H&R
> Coilovered A4 Avant, that was a truely matched set-up, cornered flat,
> (okay, most of that is due to the better chassis), responsive and
> STIFF, but a really decent ride) if they match, the ride is pretty
> decent. Both of our 200's suffered the underdamped syndrome (i.e.
> H&R's stiffer than the Bilsteins) which results in head toss and
> jiggles), his STi and my former Solo2 GTi suffered overdamping, which
> simply hammers you and the car. With Koni's, the question is the range
> of adjustment,
> if full soft is softer than Bilsteins, how stiff can you make them? (I
> do know that they adjust in jounce only, which pretty much effects
> ride quality, not so much weight transfer, which relies on rebound,
> too). With this in mind:
> With Eibachs, my bet is you're pretty safe, especially if you go with
> the Koni's, I'd bet with no more than 2 turns, you'll be able to match
> the springs well.
> With Regular H&R's, you may still be able to get the shocks into range
> in jounce. Rebound is another matter, so you still end up with a bit
> of head toss on the short duration undulations that often end up in
> the pavement when they lay it down.
> With S6+, I dunno. Since Koni's don't adjust in rebound, you may get
> head toss and jiggles. Stock Bilstein, you will definitely get that.
> Custom valved, Bilsteins, well, if you have the spring specs and
> corner weight the car, they'll be right on, until they wear. I do know
> one lister was considering the S6+ springs, but I don't know if he
> ever got them installed. He attended the ALMS LimeRock dinner
> gathering, so maybe Paul K would know. He's one whom could answer
> whether or not the S6+ springs were worth it, AND what his shock
> settings were. The only other option would be to get double adjustable
> shocks (big $$$, I think Penske's are double adjustable.....;-) to
> match the stiffer springs. After my experience with my 200Q
> (admittedly more of a noodle-y chassis than a C4, so it makes things
> worse) with underdamped springs, for a mostly street cruiser, I'd
> avoid it. Only thing worse is overdamped (my GTi was virtually not
> street drivable in the early spring when the potholes and frostheaves
> (like you have to worry about either!) weren't repaired. The hammering
> was unbearable and hurt your head. And those were Tokico Illumina 5s
> on full soft.
> LL - NY
> On 5/21/05, lebakken1 at netzero.com <lebakken1 at netzero.com> wrote:
> > Larry L. wrote:
> > "Lee is correct on the shocks. As for Eibachs, (sound like you're sold on 'em) they will not totally remove the dive, nor roll. If dive bother's you, I'd go S6+ H&R's, as for roll, really seems that the HSRB is probably the only solution (once my purchase and renovations are done, I'm going to go for one. Keep note, Hap!). On the shocks, on a personal note, since Bilstein is willing to custom valve work is relatively cheap, I'd consider doing it. The combination of Bilstein Sports seems almost dead on for Eibachs (except not enough front
> > Jounce, although I may be wanting to make shocks do the work that the
> > SPRINGS should do), which would make them too limp for either set of H&R's (standard UrS4/6 or S6+). This is the case with my 200Q, which has a horrible ride as a result. Lots of head toss.
> > As for alignment, correct would be dead stock. Then, if your camber
> > plates have the room to rotate (such as the 2-bennets), dial in as
> > much + caster as is left in the adjusters while still staying even
> > side to side. This will grip well, wear well, and if you can add
> > caster, will have better centering, on center feel and better camber
> > gain control. The only drawback of the probable availible added caster
> > is the steering can get heavy and numb if you go too far. However,
> > NONE of the camber plate options car really get that far."
> > S-fans -
> > Great write up Larry. I have recently purchased Koni adjustables on the GB, and have been thinking for quite awhile what I should do about springs. The Eibachs sound like a great way to go - if, as Taka says - you just want to appreciate this car for what it is, a big, powerful, competent, comfortable luxo-cruiser. Which, is what I want, but Audi went a bit overboard when they softened up from the the 92 urS.
> > I had 2B coilovers on my 4K; 400lb front 280lb if I remember correctly. Koni Sports. Running on 225/45-16. This was a great set up here in Seattle, where the roads are good. It also was leaning towards the stiff side of things - which I like.
> > My question is: what is the difference in the H&R Ur springs and the S6+ ? What is the difference between these and the Eibachs? Is there a lowering dimension/rate chart anywhere comparing these springs? You say the Eibachs match well with the Bilsteins - I have heard that Bilsteins tend to be stiffer than the Koni adjustables if the Koni's are set low. How will the Koni's match with any of these springs? Bottom line - I have been leaning towards the H&R's, being slightly paranoid about the inconsistencies in their design for these cars in years past.
> > Once I decide, I probably will pony up for the 2B camber plates also -Wow! them are slippery! But only the best for my S.
> > Thanks again for the info, and apologies to the list for a bunch of what I know to be redundant questions.
> > Regards,
> > Craig Lebakken
> > 94 S4
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